KR20180022221A - Method, apparatus, and system for carrier sensing on multiple carriers in unlicensed spectrum - Google Patents

Abstract

The present invention relates to a method for effectively performing clear channel assessment (CCA) during a listen-before-talk process when performing channel access for unlink channel(s) and signal transmission in unlicensed band communication. The present invention relates to a method for aligning a data transmission time, and a device and a system thereof which can perform multiplexing of terminals having scheduled uplink data. According to an embodiment of the present invention, provides are a method, a device and a system for unlicensed band communication.

Description

[0001] METHOD, APPARATUS, AND SYSTEM FOR CARRIER SENSING ON MULTIPLE CARRIERS IN UNLICENSED SPECTRUM [0002]

The present invention relates to a method for effectively performing CCA (Clear Channel Assesment) during a procedure of Listen before talk in channel access for uplink channel (s) and signal transmission in license-exempt band communication, a method for aligning a data transmission time point so that multiplexing can be performed, and a device and a system therefor.

Recently, as the spread of mobile devices has expanded, wireless LAN technology that can provide fast wireless Internet service has attracted much attention. Wireless LAN technology is a technology that enables wireless devices such as smart phones, smart pads, laptop computers, portable multimedia players, and embedded devices to wirelessly connect to the Internet at home, to be.

IEEE (Institute of Electrical and Electronics Engineers) Since 802.11 supports the initial wireless LAN technology using 2.4 GHz frequency, various technology standards are being put into practical use or under development. First, IEEE 802.11b supports a communication speed of up to 11 Mbps while using a frequency of 2.4 GHz band. IEEE 802.11a, which has been commercialized since IEEE 802.11b, uses the frequency of the 5 GHz band instead of the 2.4 GHz band, thereby reducing the influence on the interference compared to the frequency of the highly congested 2.4 GHz band. Orthogonal Frequency Division Multiplexing To improve communication speed up to 54Mbps. However, IEEE 802.11a has a short communication distance compared to IEEE 802.11b. IEEE 802.11g, like IEEE 802.11b, uses a frequency of 2.4GHz band to achieve a communication speed of up to 54Mbps and has received considerable attention because it meets backward compatibility. It is in the lead.

On the other hand, there is IEEE 802.11n as a technical standard established to overcome the limit of the communication speed pointed out as a weak point in the wireless LAN. IEEE 802.11n aims to increase the speed and reliability of the network and to extend the operating distance of the wireless network. More specifically, IEEE 802.11n supports high throughput (HT) with data rates of up to 540 Mbps or higher, and uses multiple antennas at both ends of the transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology. In addition, the specification may use a coding scheme that transfers multiple duplicate copies to increase data reliability.

As the spread of the wireless LAN is activated and the applications using it are diversified, there is a need for a new wireless LAN system to support a very high throughput (VHT) higher than the data processing speed supported by IEEE 802.11n . IEEE 802.11ac supports wide bandwidth (80MHz ~ 160MHz) at 5GHz frequency. The IEEE 802.11ac standard is defined only in the 5GHz band, but for backward compatibility with existing 2.4GHz band products, early 11ac chipsets will also support operation in the 2.4GHz band. Theoretically, according to this standard, the wireless LAN speed of multiple stations is at least 1Gbps and the maximum single link speed is at least 500Mbps. This is achieved through the expansion of the concept of wireless interfaces adopted in 802.11n, including wider radio frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multiuser MIMO, and high density modulation (up to 256 QAM) . Meanwhile, IEEE 802.11ad is a method of transmitting data using a 60 GHz band instead of the existing 2.4 GHz / 5 GHz. IEEE 802.11ad is a transmission specification that uses beamforming technology to provide speeds of up to 7 Gbps, making it suitable for high bitrate video streaming, such as large amounts of data or uncompressed HD video. However, the 60GHz frequency band has a disadvantage in that it is difficult to pass through obstacles, and therefore, it can be used only between devices in a near space.

In recent years, as a next-generation wireless LAN standard after 802.11ac and 802.11ad, there has been a continuing discussion to provide high-efficiency and high-performance wireless LAN communication technology in a high-density environment. That is, in the next generation wireless LAN environment, communication with high frequency efficiency should be provided in the presence of a high density station and an access point (AP), and various techniques are required to realize this.

Meanwhile, due to the proliferation of smart devices in recent years, mobile traffic has been increasing, and it is becoming difficult to handle the increased data usage for providing cellular communication service only in the existing authorized frequency spectrum or LTE-licensed frequency band.

In this situation, the use of unlicensed frequency spectrum or LTE-Unlicensed frequency band (for example, 2.4 GHz band, 5.8 GHz band, etc.) for providing cellular communication service is being sought as a solution to the lack of spectrum problem.

However, in the case of the unlicensed band, since the communication service provider does not secure the exclusive use of the frequency license through the auction process, and only the certain level of the adjacent band protection regulations is satisfied, a plurality of communication facilities can be used simultaneously without restriction. It is difficult to guarantee a communication quality at a level that can be achieved, and interference problems may occur with devices that are wirelessly communicating using an unlicensed band (e.g., Wi-Fi network).

Therefore, in order to establish the LTE technology in the unlicensed band, the coexistence with the existing unlicensed band device and the study for the efficient sharing of the wireless channel should be performed proactively. That is, a robust coexistence mechanism (RCM) should be developed so that devices using LTE technology in the unlicensed band do not affect existing unlicensed band devices.

Regarding standardization, telecommunication carriers such as NTT DoCoMo, China Mobile and Verizon, including manufacturers such as Qualcomm in 3GPP, actively insist on the introduction of the standard for LTE technology in the license-exempt band actively. However, many members are more cautious because they are a new technology that can shake up the existing carrier's business model based on securing the frequency of LTE technology in the licensed band. Therefore, it is expected that LTE technology in the license-exempted band will be standardized through 3GPP after Release 13, and it is expected that it will be connected to actual commercial service from the second half of 2016. In the case of foreign countries, there is a basis for commercialization of various services and new technologies without specifying usage under the conditions of compliance with the basic radio wave use etiquette in the frequency sharing band or the license-exempt small power band. On the other hand, most of the license-exempt bands including the ISM band are operated by the use designation in Korea, and technical research and related policies should be preceded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide a method, an apparatus, and a system for a license-exempt band communication.

The present invention also has a purpose of providing a carrier synchronization method for transmission with a wider bandwidth.

According to an embodiment of the present invention, a method, apparatus and system for license-exempt band communication can be provided.

According to the embodiment of the present invention described above, carrier synchronization for wider bandwidth transmission in the license-exempt band can be performed.

The present invention is applicable to various communication devices such as a station or an access point using license-exempt band communication, a station using a cellular communication, or a base station.

1 is a diagram illustrating a CSMA (Carrier Sense Multiple Access) / CA (Collision Avoidance) method used in wireless LAN communication.
2 is a diagram illustrating an embodiment of a wireless communication method using a CCA (Clear Channel Assessment) technique.
3 is a diagram illustrating an example of a superposed BSS environment.
FIG. 4 shows an example of a radio frame structure used in a wireless communication system.
FIG. 5 illustrates an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system.
6 is a view for explaining a physical channel used in a 3GPP system and a general signal transmission method using the same.
FIG. 7 illustrates a radio frame structure for transmission of a synchronization signal (SS).
8 is a diagram illustrating a structure of a downlink radio frame used in an LTE system.
FIG. 9 illustrates a configuration of a cell specific common reference signal.
10 shows an example of a UL subframe structure used in a wireless communication system.
11 is a conceptual diagram illustrating a carrier aggregation (CA) technique.
12 is a diagram for explaining Single Carrier Communication and Multiple Carrier Communication.
13 is a diagram showing an example in which a cross carrier scheduling technique is applied.
FIG. 14 is a diagram for explaining a licensed assisted access (LAA) service environment.
15 is a diagram illustrating a deployment scenario of a terminal and a base station in an LAA service environment.
16 is a block diagram showing a configuration of a terminal and a base station according to an embodiment of the present invention.
17 is a block diagram illustrating a category-4 LBT procedure in an LAA according to an embodiment of the present invention.
18 is a block diagram illustrating a category-4 LBT procedure in an LAA according to another embodiment of the present invention.
FIG. 19 shows an example of a case where a channel is idle as one embodiment of the present invention. The channel priority class 3 is used as a defer duration, and 19- (a) and a channel priority class 3 extracted as Ninit = 1 (B), where Ninit = 0 is extracted.
FIG. 20 illustrates an example of a case where a channel is busy in one slot, using channel priority class 3 as a defer duration and 20- (a) extracted from Ninit = 2 and channel priority class 3 as an embodiment of the present invention (B) in which Ninit = 1 is extracted.
21 is a diagram illustrating a case where UL transmission is continuously transmitted after Ongoing DL transmission according to an embodiment of the present invention.
FIG. 22 is a diagram illustrating a case in which UL transmission is consecutively transmitted after DL transmission, and a DL that receives an UL grant and a DL that precedes UL transmission are discontinuous.
23 is a diagram illustrating a case where a PDCCH including only an UL grant is transmitted without PDSCH transmission in any one subframe according to an embodiment of the present invention.
FIG. 24 is a diagram illustrating a case where an EPDCCH including only an UL grant is transmitted without transmitting a PDSCH to an arbitrary subframe according to an embodiment of the present invention.
FIG. 25 is a diagram illustrating a case where a subframe that transmits only an UL grant and an LBT of a subframe (s) that performs PDSCH transmission are independently performed without PDSCH transmission as an embodiment of the present invention.
26 is a diagram illustrating a case where a reservation signal (s) is transmitted to a blanked OFDM symbol (s) in a subframe transmitting a PDCCH including only an UL grant without PDSCH transmission in any one subframe according to an embodiment of the present invention .
FIG. 27 is a diagram illustrating a method of switching an LBT type when a base station informs a terminal of an LBT type through an UL grant and a DL scheduling occurs between an UL grant transmission and a corresponding UL transmission, according to an embodiment of the present invention.
FIG. 28 is a diagram illustrating a method of switching an LBT type when a base station informs a terminal of an LBT type through an UL grant and DL scheduling occurs between an UL grant transmission and a corresponding UL transmission. FIG.
FIG. 29 is a diagram illustrating a method of switching an LBT type when a base station informs a terminal of an LBT type through an UL grant and DL scheduling occurs between an UL grant transmission and a corresponding UL transmission. FIG.
FIG. 30 is a diagram illustrating a method of scheduling a UL transmission burst without an LBT gap between consecutive UL subframes (s) of a UL to a mobile station according to an embodiment of the present invention.
31 is a diagram illustrating a method of scheduling a UL subframe (s) of an UL transmission burst with an LBT gap between consecutive UL subframes at the time of performing scheduling, according to another embodiment of the present invention.
32 is a diagram illustrating a structure for UL radio frame, UL subframe, and UL slot in a subframe in LTE.
FIG. 33 is a diagram illustrating a case of receiving an LBT type change signaling. FIG.
FIG. 34 relates to the case where a base station intends to transmit on the LAA SCell on a multi-carrier from a mobile station to instruct each carrier to have a different UL LBT type by self-carrier scheduling of the UL grant (s).
FIG. 35 illustrates an embodiment of the present invention in which the BS intends to transmit on the LAA SCell on a multi-carrier from the UE to instruct the UL LBT type to be different for each carrier by self-carrier scheduling of the UL grant And the uplink multi-carrier transmission operation in case of LBT failure in cat-4 LBT carrier (s).
FIG. 36 illustrates another embodiment of the present invention. In FIG. 36, a BS performs transmission of UL grant (s) on a LAA SCell on a multi-carrier from a mobile station by self-carrier scheduling, LBT type is instructed.
FIG. 37 shows another embodiment of the present invention, in which a base station performs self-carrier scheduling of an UL grant (s) by intending to transmit on a LAA SCell on a multi-carrier from a mobile station, and performs multiple subframe scheduling, UL sub-frame (UL sub-frame), UL sub-frame (UL sub-frame), and UL sub-frame (UL sub-frame).
FIG. 38 shows another embodiment of the present invention in which a base station performs self-carrier scheduling of an UL grant (s) by intending to transmit on the LAA SCell on a multiple carrier from a mobile station, and performs multiple subframe scheduling. UL sub-frame, the UL grant (s) may be transmitted from the same downlink subframe or the UL grant (s) may be transmitted from the different downlink subframe to the UL sub-frame, The user is instructed to do so.

As used herein, terms used in the present invention are selected from general terms that are widely used in the present invention while taking into account the functions of the present invention. However, these terms may vary depending on the intention of a person skilled in the art, custom or the emergence of new technology. Also, in certain cases, there may be a term arbitrarily selected by the applicant, and in this case, the meaning thereof will be described in the description of the corresponding invention. Therefore, it is intended that the terminology used herein should be interpreted relative to the actual meaning of the term, rather than the nomenclature, and its content throughout the specification.

Throughout the specification, when a configuration is referred to as being "connected" to another configuration, it is not limited to the case where it is "directly connected," but also includes "electrically connected" do. Also, when an element is referred to as " including " a specific element, it is meant to include other elements, rather than excluding other elements, unless the context clearly dictates otherwise. In addition, the limitations of " above " or " below ", respectively, based on a specific threshold value may be appropriately replaced with "

1 shows a CSMA (Collision Avoidance) / CA (Collision Avoidance) method used in wireless LAN communication.

A terminal performing wireless LAN communication carries out carrier sensing before transmitting data to check whether a channel is busy or not. If a radio signal of a predetermined intensity or more is detected, the corresponding channel is determined to be in a busy state, and the terminal delays access to the corresponding channel. This process is called Clear Channel Assessment (CCA), and the level at which the signal is detected is called the CCA threshold. If a radio signal equal to or higher than the CCA threshold value received by the terminal causes the terminal to be the receiver, the terminal processes the received radio signal. On the other hand, when a radio signal is not detected in the corresponding channel or a radio signal having an intensity lower than the CCA threshold value is detected, the channel is determined to be in an idle state.

If it is determined that the channel is empty, each terminal having data to be transmitted performs an IFS (InterFrame Space) according to the situation of each terminal, such as AIFS (Arbitration IFS), PIFS (PCF IFS) . According to the embodiment, the AIFS can be used as a substitute for the existing DIFS (DCF IFS). That is, each UE waits for a slot time equal to a random number allocated to the corresponding UE for an interval of an empty state of the channel and waits for a terminal having exhausted the slot time to access the corresponding channel . The interval during which each terminal performs the backoff procedure is referred to as a contention window period.

If a specific terminal successfully accesses the channel, the terminal can transmit data through the channel. However, if the terminal attempting to access collides with another terminal, the collided terminals are each assigned a new random number and perform the backoff procedure again. According to an embodiment, a random number newly assigned to each terminal can be determined within a range of twice the random number range previously allocated to the terminal. Meanwhile, each terminal attempts access again by performing a backoff procedure in the next contention window interval, and each terminal performs a backoff procedure from the slot time remaining in the previous contention window interval. Each terminal that performs wireless LAN communication in this manner can avoid collision of a specific channel with each other.

FIG. 2 shows an embodiment of a wireless communication method using the CCA technique.

In the wireless communication, for example, in the wireless LAN communication, it is possible to detect whether or not the channel is used through the CCA. At this time, CCA methods used include Signal Detection (SD), Energy Detection (ED), Correlation Detection (CD), and the like.

First, signal detection (CCA-SD) is a method of measuring the signal strength of a preamble of a wireless LAN (i.e., 802.11) frame. This method has a disadvantage in that it can perform stable signal detection but operate only in the initial part of a frame in which a preamble exists. According to one embodiment, signal detection may be used for CCAs for a Primary Channel in a broadband wireless LAN. Next, Energy Detection (CCA-ED) is a method of detecting the energy of all signals received above a certain threshold. This method can be used to detect signals such as Bluetooth, ZigBee, etc. that normally do not detect the preamble. The method may also be used for CCAs in a secondary channel that do not keep track of the signal. Correlation detection (CCA-CD) is a method of detecting a signal level in the middle of a wireless LAN frame, and utilizes the fact that a wireless LAN signal has a repetitive pattern of a periodic OFDM signal. That is, the correlation detection method detects the signal strength of the repeated patterns of the OFDM signal symbol after receiving the wireless LAN data for an arbitrary time.

According to the embodiment of the present invention, the access of the terminal to the channel can be controlled by using the predetermined CCA threshold value for each CCA method. In the embodiment of FIG. 2, the CCA-ED threshold value 10 represents a preset threshold value for performing energy detection, and the CCA-SD threshold value 30 represents a predetermined threshold value for performing signal detection. Also, the RX sensitivity (50) represents the minimum signal strength at which the UE can decode the radio signal. According to the embodiment, the reception sensitivity 50 may be set to a level equal to or lower than the CCA-SD threshold value 30 according to the performance and setting of the terminal. Further, the CCA-ED threshold value 10 may be set to a level higher than the CCA-SD threshold value 30. For example, the CCA-ED threshold value 10 may be set to -62 dBm, and the CCA-SD threshold value 30 may be set to -82 dBm. However, the present invention is not limited to this, and the CCA-ED threshold value 10 and the CCA-SD threshold value 30 may be set differently depending on whether they are threshold values for the main channel, .

According to the embodiment of FIG. 2, each UE measures a received signal strength indicator (RX RSSI) of a received radio signal, and based on the comparison result between the measured received signal strength and the set CCA threshold value To determine the channel state.

First, if the radio signal 350 received at a specific channel has a received signal strength RX RSSI equal to or less than the CCA-SD threshold value 30, the channel is determined to be empty. Accordingly, the received signal is not processed or protected by the terminal, and each terminal can attempt to access the channel according to the method described in FIG.

If the wireless LAN signal 330 having the received signal strength RX RSSI equal to or higher than the CCA-SD threshold value 30 is received in a specific channel, the corresponding channel is determined to be in the use state. Therefore, the terminal receiving the signal delays access to the channel. According to an exemplary embodiment, the UE can use the signal pattern of the preamble portion of the received radio signal to determine whether the corresponding signal is a WLAN signal. According to the embodiment of FIG. 2, each terminal determines that the channel is in use even when a wireless LAN signal of the same BSS as the corresponding terminal, as well as a wireless LAN signal of another BSS is received.

On the other hand, when the radio signal 310 having the received signal strength RX RSSI equal to or higher than the CCA-ED threshold value 10 is received in a specific channel, the corresponding channel is determined to be in the use state. At this time, the terminal determines that the channel is in the use state when the received signal strength of the signal is equal to or higher than the CCA-ED threshold value (10) even when a wireless signal other than the wireless LAN signal is received. Therefore, the terminal receiving the signal delays access to the channel.

FIG. 3 illustrates an example of an overlapping BSS (OBSS) environment. In FIG. 3, station 1 (STA-1) and station 2 (STA-2) are associated with AP-1 in BSS-1 operated by AP- Station 3 (STA-3) and station 4 (STA-4) are combined with AP-2. In the overlapping BSS environment of FIG. 3, at least some of the communication coverage of BSS-1 and BSS-2 are overlapped.

As shown in FIG. 3, when the STA-3 transmits upload data to the AP-2, the STA-2 of the BSS-1 located nearby can continuously interfere with the STA-2. At this time, co-channel interference (CCI) interference is generated when BSS-1 and BSS-2 use the same frequency band (for example, 2.4 GHz and 5 GHz) and the same primary channel. . In addition, the interference generated when the BSS-1 and BSS-2 use the adjacent main channel is referred to as Adjacent Channel Interference (ACI). The CCI or ACI may be received with a signal strength higher than the CCA threshold of STA-2 (e.g. CCA-SD threshold), depending on the distance between STA-2 and STA-3. If this interference is received at the STA-2 with an intensity higher than the CCA threshold, the STA-2 recognizes that the channel is in use and delays the uploading of data to the AP-1. However, since STA-2 and STA-3 are stations belonging to different BSS, if STA-2 increases CCA threshold, STA-2 and STA-3 simultaneously upload to AP-1 and AP-2 So that the effect of spatial reuse can be obtained.

On the other hand, in FIG. 3, upload data transmission of STA-3 in BSS-2 interferes with STA-4 belonging to the same BSS-2. At this time, if the CCA threshold value of STA-4 is increased to be equal to that of STA-2, STA-3 and STA-4 belonging to the same BSS transmit upload data to AP-2 simultaneously. Therefore, in order to raise the CCA threshold for arbitrary interference, it is necessary to determine whether the interference is caused by a signal belonging to the same BSS or by a signal belonging to another BSS. For this purpose, each mobile station must identify the BSS identifier of the received WLAN signal or any other type of information that can distinguish the BSS. In addition, it is desirable that the confirmation of the BSS information is performed within a short time in which the CCA process is performed.

4 shows an example of a radio frame structure used in a wireless communication system.

Particularly, FIG. 4A shows a frame structure for a frequency division duplex (FDD) used in a 3GPP LTE / LTE-A system and FIG. 4B shows a frame structure used in a 3GPP LTE / Time division duplex (TDD) frame structure.

Referring to FIG. 4, a radio frame used in the 3GPP LTE / LTE-A system has a length of 10 ms (307200 Ts) and consists of 10 equal sized subframes (SF). 10 subframes within one radio frame may be assigned respective numbers. Here, Ts represents the sampling time, and is represented by Ts = 1 / (2048 * 15 kHz). Each subframe is 1 ms long and consists of two slots. 20 slots in one radio frame can be sequentially numbered from 0 to 19. [ Each slot has a length of 0.5 ms. The time for transmitting one subframe is defined as a Transmission Time Interval (TTI). The time resource may be classified by a radio frame number (or a radio frame index), a subframe number (also referred to as a subframe number), a slot number (or a slot index), and the like.

The wireless frame may be configured differently according to the duplex mode. For example, in the FDD mode, since the downlink transmission and the uplink transmission are divided by frequency, the radio frame includes only one of the downlink subframe and the uplink subframe for a specific frequency band. In the TDD mode, since the downlink transmission and the uplink transmission are divided by time, the radio frame includes both the downlink subframe and the uplink subframe for a specific frequency band.

Table 1 illustrates the DL-UL configuration of subframes in a radio frame in TDD mode.

In Table 1, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe. The specific subframe includes three fields of Downlink Pilot Time Slot (DwPTS), Guard Period (GP), and UpPTS (Uplink Pilot Time Slot). DwPTS is a time interval reserved for downlink transmission, and UpPTS is a time interval reserved for uplink transmission. Table 2 illustrates the configuration of the singular frames.

FIG. 5 shows an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, FIG. 5 shows the structure of the resource grid of the 3GPP LTE / LTE-A system. There is one resource grid per antenna port. Referring to FIG. 5, a slot includes a plurality of OFDM symbols in a time domain and a plurality of resource blocks (RBs) in a frequency domain. The OFDM symbol also means one symbol period. Referring to FIG. 5, a signal transmitted in each slot may be expressed as a resource grid consisting of N ^{DL / UL} _RB * N ^RB _sc subcarriers and N ^{DL / UL} _symb OFDM symbols. have. Here, N ^DL _RB represents the number of resource blocks (RBs) in the downlink slot, and N ^UL _RB represents the number of _RBs in the UL slot. N ^DL _RB and N ^UL _RB depend on the DL transmission bandwidth and the UL transmission bandwidth, respectively. N ^DL _symb denotes the number of OFDM symbols in the downlink slot, and N ^UL _symb denotes the number of OFDM symbols in the UL slot. N ^RB _sc represents the number of subcarriers constituting one RB. The OFDM symbol may be referred to as an OFDM symbol, an SC-FDM (Single Carrier Frequency Division Multiplexing) symbol, or the like according to a multiple access scheme. The number of OFDM symbols included in one slot can be variously changed according to the channel bandwidth and the length of the cyclic prefix (CP). For example, in the case of a normal CP, one slot includes 7 OFDM symbols

In the case of an extended CP, one slot includes six OFDM symbols. Although FIG. 5 illustrates a subframe in which one slot is composed of seven OFDM symbols, embodiments of the present invention may be applied to subframes having a different number of OFDM symbols in the same manner. Referring to FIG. 5, each OFDM symbol includes N ^{DL / UL} _RB * N ^RB _sc subcarriers in the frequency domain. The type of subcarrier may be a data subcarrier for data transmission, a reference signal subcarrier for transmission of a reference signal, a null subcarrier for a guard band or a direct current (DC) ≪ / RTI > The DC component is mapped to a carrier frequency (f ₀ ) in an OFDM signal generation process or a frequency up-conversion process. The carrier frequency is also referred to as the center frequency (f _c ).

One RB is defined as N ^{DL / UL} _symb consecutive OFDM symbols in the time domain (for example, seven), and N ^RB _scrambled (e.g., twelve) consecutive subcarriers in the frequency domain . For reference, a resource composed of one OFDM symbol and one subcarrier is referred to as a resource element (RE) or tone. Therefore, one RB consists of N ^{DL / UL} _symb * N ^RB _sc resource elements. Each resource element in the resource grid can be uniquely defined by an index pair (k, 1) in one slot. k is an index assigned from 0 to N ^{DL / UL} _RB * N ^RBsc -1 in the frequency domain, and 1 is an index assigned from 0 to N ^{DL / UL} _symb -1 in the time domain.

One RB is mapped to one physical resource block (PRB) and one virtual resource block (VRB). The PRB is defined as N ^{DL / UL} _symb (e.g., 7) consecutive OFDM symbols or SC-FDM symbols in the time domain, and N ^RB _scrambled (e.g., twelve) Is defined by the subcarrier. Therefore, one PRB consists of N ^{DL / UL} _symb * N ^RB _sc resource elements. Two RBs, one in each of two slots of the subframe occupying N ^RB _sc consecutive identical subcarriers in one subframe, are called a PRB pair. The two RBs constituting the PRB pair have the same PRB number (or PRB index).

In order for the UE to receive a signal from the eNB or to transmit a signal to the eNB, the time / frequency synchronization of the UE should be synchronized with the time / frequency synchronization of the eNB. since it can determine the time and frequency parameters necessary for the UE to perform the demodulation of the DL signal and the transmission of the UL signal at the correct time, as long as it is synchronized with the eNB.

6 is a view for explaining a physical channel used in a 3GPP system and a general signal transmission method using the same.

The terminal performs an initial cell search operation such as synchronizing with the base station when the power source is large or newly enters the cell (S301). To this end, the terminal receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from a base station and synchronizes with the base station and acquires information such as a cell ID have. Then, the terminal can receive the physical broadcast channel from the base station and acquire the in-cell broadcast information. Meanwhile, the UE can receive the downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE receives more detailed system information by receiving a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH) according to the information on the PDCCH (S302).

On the other hand, if the base station is initially connected or there is no radio resource for signal transmission, the terminal can perform a random access procedure (RACH) on the base station (steps S303 to S306). To this end, the UE transmits a specific sequence through a Physical Random Access Channel (PRACH) (S303 and S305), and receives a response message for the preamble on the PDCCH and the corresponding PDSCH S304 and S306). In case of the contention-based RACH, a contention resolution procedure can be additionally performed.

The UE having performed the procedure described above transmits PDCCH / PDSCH reception (S307) and physical uplink shared channel (PUSCH) / physical uplink control channel Control Channel, PUCCH) (S308). In particular, the UE receives downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the UE, and formats are different according to the purpose of use.

Meanwhile, the control information that the UE transmits to the base station through the uplink or receives from the base station includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI) ) And the like. In the case of the 3GPP LTE system, the UE can transmit control information such as CQI / PMI / RI as described above through PUSCH and / or PUCCH.

FIG. 7 illustrates a radio frame structure for transmission of a synchronization signal (SS). Particularly, FIG. 7 illustrates a radio frame structure for transmission of a synchronization signal and a PBCH in a frequency division duplex (FDD). FIG. 7A illustrates a radio frame composed of a normal CP (normal cyclic prefix) SS and PBCH. FIG. 7 (b) shows transmission positions of the SS and the PBCH in a radio frame configured by an extended CP.

The UE obtains time and frequency synchronization with the cell when it is powered on or newly connected to the cell, and performs cell search such as detecting the physical cell identity N ^cell _ID of the cell cell search procedure. To this end, the UE receives a synchronization signal, for example, a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the eNB, synchronizes with the eNB, , ID) can be obtained.

Referring to FIG. 7, the SS will be described in more detail as follows. SS is divided into PSS and SSS. PSS is used to obtain time domain synchronization and / or frequency domain synchronization such as OFDM symbol synchronization, slot synchronization, and the like. SSS is used for frame synchronization, cell group ID, and / or cell CP configuration Information). Referring to FIG. 7, the PSS and the SSS are transmitted in two OFDM symbols of each radio frame, respectively. In order to facilitate inter Radio Access Technology ("RAT") measurement, the SS considers 4.6 ms, which is the Global System for Mobile communication (GSM) frame length, in the first slot of subframe 0 and the first slot of subframe 5 Respectively. Specifically, the PSS is transmitted in the last OFDM symbol of the first slot of the subframe 0 and the last OFDM symbol of the first slot of the subframe 5, respectively, and the SSS is transmitted from the second OFDM symbol at the end of the first slot of the subframe 0, Lt; RTI ID = 0.0 > OFDM < / RTI > The boundary of the corresponding radio frame can be detected through the SSS. The PSS is transmitted in the last OFDM symbol of the slot and the SSS is transmitted in the OFDM symbol immediately before the PSS. SS's transmit diversity scheme uses only a single antenna port and is not defined in the standard. That is, a single antenna port transmission or a UE transparent transmission scheme (e.g., Precoding Vector Switching (PVS), Time Switched Diversity (TSTD), Cyclic Delay Diversity (CDD)) can be used for SS transmission diversity .

The SS can represent a total of 504 unique physical layer cell IDs through a combination of three PSSs and 168 SSs. In other words, the physical layer cell IDs are allocated to 168 physical-layer cell-identifier groups, each group including three unique identifiers, such that each physical-layer cell ID is part of only one physical-layer cell- . Thus, the physical layer cell ID _{^{N cell ID = 3N (1)}} ID + N (2) ID is a physical-layer cell - the range of 0 [identifier group to the 167 number N ⁽¹⁾ _ID and the physical-layer cell - a unique number N ⁽²⁾ _ID of 0 to 2 indicating the physical-layer identifier in the identifier group. The UE may detect the PSS to know one of the three unique physical-layer identifiers and may detect the SSS to identify one of the 168 physical layer cell IDs associated with the physical-layer identifier. A ZC (Zadoff-Chu) sequence of length 63 is defined in the frequency domain and used as the PSS.

Referring to FIG. 7, since the PSS is transmitted every 5 ms, the UE can detect that the corresponding subframe is one of the subframe 0 and the subframe 5 by detecting the PSS. However, I do not know what it is. Therefore, the UE can not recognize the boundary of the radio frame only by the PSS. That is, frame synchronization can not be obtained with only PSS. The UE detects an SSS transmitted twice in one radio frame but transmitted as a different sequence and detects the boundary of the radio frame.

8 is a diagram illustrating a control channel included in a control region of one subframe in a downlink radio frame.

Referring to FIG. 8, a subframe is composed of 14 OFDM symbols. According to the subframe setting, the first to third OFDM symbols are used as a control region and the remaining 13 to 11 OFDM symbols are used as a data region. In the figure, R1 to R4 represent a reference signal (RS) or pilot signal for antennas 0 to 3. The RS is fixed in a constant pattern in the subframe regardless of the control region and the data region. The control channel is allocated to a resource to which the RS is not allocated in the control region, and the traffic channel is also allocated to the resource to which the RS is not allocated in the data region. Control channels allocated to the control region include a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid-ARQ Indicator CHannel (PHICH), and a Physical Downlink Control Channel (PDCCH).

The PCFICH informs the UE of the number of OFDM symbols used in the PDCCH for each subframe as a physical control format indicator channel. The PCFICH is located in the first OFDM symbol and is set prior to the PHICH and PDCCH. The PCFICH is composed of four REGs (Resource Element Groups), and each REG is distributed in the control area based on the cell ID (Cell IDentity). One REG is composed of four REs (Resource Elements). RE denotes a minimum physical resource defined by one subcarrier x one OFDM symbol. The PCFICH value indicates a value of 1 to 3 or 2 to 4 depending on the bandwidth and is modulated by Quadrature Phase Shift Keying (QPSK).

The PHICH is used as a physical HARQ (Hybrid Automatic Repeat and Request) indicator channel to carry HARQ ACK / NACK for uplink transmission. That is, the PHICH indicates a channel through which DL ACK / NACK information for UL HARQ is transmitted. The PHICH consists of one REG and is cell-specific scrambled. The ACK / NACK is indicated by 1 bit and is modulated by BPSK (Binary Phase Shift Keying). The modulated ACK / NACK is spread with a spreading factor (SF) = 2 or 4. A plurality of PHICHs mapped to the same resource constitute a PHICH group. The number of PHICHs multiplexed into the PHICH group is determined by the number of spreading codes. The PHICH (group) is repetitized three times to obtain the diversity gain in the frequency domain and / or the time domain.

The PDCCH is allocated to the first n OFDM symbols of the subframe as the physical downlink control channel. Here, n is an integer of 1 or more and is indicated by the PCFICH. The PDCCH consists of one or more CCEs. The PDCCH notifies each terminal or group of terminals of information related to resource allocation of a paging channel (PCH) and a downlink-shared channel (DL-SCH), an uplink scheduling grant, and HARQ information. A paging channel (PCH) and a downlink-shared channel (DLSCH) are transmitted on the PDSCH. Therefore, the BS and the MS generally transmit and receive data via the PDSCH, except for specific control information or specific service data.

PDSCH data is transmitted to a terminal (one or a plurality of terminals), and information on how the terminals receive and decode PDSCH data is included in the PDCCH and transmitted. For example, if a particular PDCCH is CRC masked with an RNTI (Radio Network Temporary Identity) of "A ", and a DCI format called " C" Assume that information on data to be transmitted using information (e.g., transport block size, modulation scheme, coding information, etc.) is transmitted through a specific subframe. In this case, the UE in the cell monitors the PDCCH using its RNTI information, and if there is more than one UE having the "A" RNTI, the UEs receive the PDCCH, B "and" C ".

Figure 9 illustrates the configuration of a cell specific common reference signal. In particular, FIG. 9 illustrates a CRS structure for a 3GPP LTE system supporting up to four antennas.

Where k is a subcarrier index, 1 is an OFDM symbol index, p is an antenna port number, and ^{Nmax and DL} _RB represent the largest downlink bandwidth configuration, expressed as an integer multiple of N ^RB _sc .

The variables v and v _shift define positions in the frequency domain for different RSs, and v is given by

Where n _s is the slot number in the radio frame and the cell specific frequency transition is given by:

Referring to FIG. 9 and Equations 1 and 2, the current 3GPP LTE / LTE-A standard specifies that a cell-specific CRS used for demodulation and channel measurement among various RSs defined in a corresponding system is a carrier- To be transmitted over the entire downlink band. Also, in the 3GPP LTE / LTE-A system, the cell-specific CRS is used for demodulation of the downlink data signal, and thus is transmitted every antenna port for downlink transmission.

Meanwhile, the cell-specific CRS can be used not only for channel state measurement and data demodulation, but also for tracking after the UE acquires time synchronization and frequency synchronization of a carrier used for communication with the UE, It is also used for tracking.

10 shows an example of a UL subframe structure used in a wireless communication system.

Referring to FIG. 10, the UL subframe may be divided into a control domain and a data domain in the frequency domain. One or several physical uplink control channels (PUCCHs) may be assigned to the control region to carry uplink control information (UCI). One or several physical uplink shared channels (PUSCHs) may be allocated to the data area of the UL subframe to carry user data.

In the UL subframe, subcarriers far away from each other based on a DC (Direct Current) subcarrier are used as a control region. In other words, the subcarriers located at both ends of the UL transmission bandwidth are allocated for transmission of the UL control information. The DC subcarrier is a component that is left unused for signal transmission and is mapped to the carrier frequency f ₀ in the frequency up conversion process. In one subframe, the PUCCH for one UE is allocated to an RB pair belonging to resources operating at one carrier frequency, and RBs belonging to the RB pair occupy different subcarriers in two slots. The PUCCH allocated as described above is expressed as the RB pair allocated to the PUCCH is frequency hopped at the slot boundary. However, when frequency hopping is not applied, the RB pairs occupy the same subcarrier.

The PUCCH may be used to transmit the following control information.

- SR (Scheduling Request): Information used for requesting uplink UL-SCH resources. OOK (On-Off Keying) method.

- HARQ-ACK: A response to the PDCCH and / or a response to a downlink data packet (eg, codeword) on the PDSCH.

Indicates whether PDCCH or PDSCH has been successfully received. In response to a single downlink codeword, one bit of HARQACK is transmitted and two bits of HARQ-ACK are transmitted in response to two downlink codewords. The HARQ-ACK response includes positive ACK (simply ACK), negative ACK (NACK), DTX (Discontinuous Transmission) or NACK / DTX. Here, the term HARQ-ACK is mixed with HARQ ACK / NACK and ACK / NACK.

- CSI (Channel State Information): Feedback information for the downlink channel. Multiple Input Multiple Output (MIMO) -related feedback information includes RI (Rank Indicator) and PMI (Precoding Matrix Indicator).

Hereinafter, a carrier aggregation technique will be described. 11 is a conceptual diagram illustrating carrier aggregation.

Carrier aggregation is a technique in which a radio communication system uses a frequency block or a (logical sense) cell composed of uplink resources (or component carriers) and / or downlink resources (or component carriers) Which is used as a single large logical frequency band. Hereinafter, the term "component carrier" is used for the convenience of description.

Referring to FIG. 11, the total system bandwidth (System Bandwidth, System BW) has a maximum bandwidth of 100 MHz as a logical bandwidth. The total system bandwidth includes five component carriers, each of which has a bandwidth of up to 20 MHz. A component carrier comprises one or more contiguous subcarriers physically contiguous. In FIG. 11, each of the component carriers is shown to have the same bandwidth, but this is merely an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other in the frequency domain, this figure is shown in a logical concept, wherein each component carrier may physically be adjacent to or spaced from one another.

The center frequency may use different common carriers for each component carrier or common for physically contiguous component carriers. For example, assuming that all the component carriers are physically adjacent in FIG. 11, the center carrier A can be used. Further, assuming that the respective component carriers are not physically adjacent to each other, the center carrier A, the center carrier B, and the like can be used separately for each component carrier.

In this specification, the component carrier may correspond to the system band of the legacy system. By defining a component carrier based on a legacy system, it is possible to provide backward compatibility and system design in a wireless communication environment in which an evolved terminal and a legacy terminal coexist. In one example, if the LTE-A system supports carrier aggregation, each component carrier may correspond to the system band of the LTE system. In this case, the component carrier may have any of the following bandwidths: 1.25, 2.5, 5, 10, or 20 Mhz.

The frequency band used for communication with each terminal when the entire system band is expanded by carrier aggregation is defined in units of component carriers. Terminal A can use 100 MHz, which is the entire system band, and performs communication using all five component carriers. The terminals B1 to B5 can use only a 20 MHz bandwidth and perform communication using one component carrier. Terminals C ₁ and C ₂ can use a 40 MHz bandwidth and each communicate using two component carriers. The two component carriers may be logically / physically adjacent or non-contiguous. The terminal C ₁ shows a case in which two non-adjacent component carriers are used and the terminal C ₂ shows a case in which two adjacent component carriers are used.

In the LTE system, one downlink component carrier and one uplink component carrier are used, while in the LTE-A system, a plurality of component carriers can be used as shown in FIG. A combination of a downlink component carrier or a corresponding downlink component carrier and a corresponding uplink component carrier may be referred to as a cell and a corresponding relationship between a downlink component carrier and an uplink component carrier may be indicated through system information .

At this time, the scheme of scheduling the data channel by the control channel may be classified into a link carrier scheduling method and a cross carrier scheduling method.

More specifically, link carrier scheduling schedules data channels only through the particular component carrier, such as existing LTE systems that use a single component carrier, over a particular component carrier. That is, the downlink grant / uplink grant transmitted to the PDCCH region of the downlink component carrier of a specific component carrier (or specific cell) can be scheduled only for the PDSCH / PUSCH of the cell to which the corresponding downlink component carrier belongs. That is, the search space, which is an area for attempting to detect the downlink grant / uplink grant, exists in the PDCCH region of the cell where the PDSCH / PUSCH to be scheduled is located.

On the other hand, in the cross carrier scheduling, when a control channel transmitted through a primary component carrier (Primary CC) using a Carrier Indicator Field (CIF) is transmitted through the main component carrier or through another component carrier Schedules the channel. In other words, a monitored cell (Monitored Cell or Monitored CC) of the cross-carrier scheduling is set, and the downlink grant / uplink grant transmitted in the PDCCH region of the monitored cell is set to PDSCH / PUSCH of a cell set to be scheduled in the corresponding cell Scheduling. That is, a search area for a plurality of component carriers is present in a PDCCH area of a cell to be monitored. Among the plurality of cells, system information is transmitted, an initial access attempt is made, and the PCell is set by transmission of uplink control information. The PCell is a downlink main component carrier and an uplink main component carrier corresponding to the downlink main component carrier .

12 is a diagram for explaining single carrier communication and multiple carrier communication. Particularly, Fig. 12 (a) shows a subframe structure of a single carrier and Fig. 12 (b) shows a subframe structure of multiple carriers.

Referring to FIG. 12A, a general wireless communication system performs data transmission or reception (in a frequency division duplex (FDD) mode) through one DL band and one UL band corresponding thereto , A radio frame is divided into an uplink time unit and a downlink time unit in a time domain and data transmission or reception is performed through an uplink / downlink time unit (time division duplex , TDD) mode). However, in recent wireless communication systems, introduction of a carrier aggregation technique using a larger UL / DL bandwidth by collecting a plurality of UL and / or DL frequency blocks in order to use a wider frequency band is being discussed. Carrier aggregation is an orthogonal frequency division multiplexing (OFDM) scheme that performs DL or UL communication by putting a fundamental frequency band divided into a plurality of orthogonal subcarriers on one carrier frequency in that DL or UL communication is performed using a plurality of carrier frequencies division multiplexing system. Hereinafter, each of the carriers collected by carrier aggregation is referred to as a component carrier (CC). Referring to FIG. 12 (b), three 20 MHz CCs can be aggregated into the UL and the DL, respectively, and a bandwidth of 60 MHz can be supported. Each CC may be adjacent or non-adjacent to one another in the frequency domain. FIG. 12 (b) shows a case where the bandwidth of the UL CC and the bandwidth of the DL CC are the same and symmetric, but the bandwidth of each CC can be set independently. Asymmetric carrier aggregation in which the number of UL CCs is different from the number of DL CCs is also possible. A DL / UL CC specific to a particular UE may be referred to as a configured serving UL / DL CC in a particular UE.

The eNB may be used to communicate with the UE by activating some or all of the serving CCs configured in the UE, or by deactivating some CCs. The eNB can change the CC to be activated / deactivated, and can change the number of CCs to be activated / deactivated. When the eNB allocates a CC available for the UE in a cell-specific or UE-specific manner, at least one of the assigned CCs is used, as long as the CC allocation for the UE is not completely reconfigured or the UE does not perform a handover. One is not disabled. A CC that is not deactivated is referred to as a primary CC (PCC), and a CC that can be freely activated / deactivated by the eNB is called a secondary CC (SCC), unless it is a full reconfiguration of the CC assignment to the UE It is called. PCC and SCC may be distinguished based on control information. For example, specific control information may be set to be transmitted and received only via a specific CC, which may be referred to as PCC and the remaining CC (s) as SCC (s).

Meanwhile, 3GPP LTE (-A) uses the concept of a cell to manage radio resources. A cell is defined as a combination of DL resources and UL resources, that is, a combination of DL CC and UL CC. A cell may consist of DL resources alone, or a combination of DL resources and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of the DL resource (or DL CC) and the carrier frequency of the UL resource (or UL CC) . For example, a combination of a DL resource and a UL resource can be indicated by linkage of System Information Block Type 2 (SIB2). Here, the carrier frequency means a center frequency of each cell or CC. In the following,

a cell operating on a frequency is referred to as a primary cell or a PCC and a cell operating on a secondary frequency (or SCC) is referred to as a secondary cell (SCell) It is called. The carrier corresponding to PCell in the downlink is referred to as a downlink primary CC (DL PCC), and the carrier corresponding to PCell in the uplink is referred to as a UL primary CC (DL PCC). SCell refers to a cell that is configurable after a Radio Resource Control (RRC) connection is established and can be used to provide additional radio resources. Depending on the capabilities of the UE, a SCell may form together with the PCell a set of serving cells for the UE. The carrier corresponding to the SCell in the downlink is referred to as DL secondary CC (DL SCC), and the carrier corresponding to the SCell in the uplink is referred to as UL secondary CC (UL SCC)

do. For UEs that are in the RRC_CONNECTED state but no carrier aggregation is set or that do not support carrier aggregation, there is only one serving cell consisting of only PCell.

As previously mentioned, the term cell used in carrier aggregation is distinguished from the term cell, which refers to a geographical area in which a communication service is provided by a single eNB or a group of antennas. In order to distinguish between a cell designating a certain geographical area and a cell of carrier aggregation, a carrier aggregation cell is referred to as a CC and a cell in a geographical area is referred to as a cell. Quot;

In the existing LTE / LTE-A system, when multiple CCs are used together, it is assumed that the UL / DL frame time synchronization of the SCC coincides with the time synchronization of the PCC, assuming that the CCs that are not so far away in the frequency domain are clustered. However, there is a possibility that a plurality of CCs belonging to different frequency bands or spaced apart from each other in frequency, that is, a plurality of CCs having different propagation characteristics, may be gathered in the future. In this case, assuming that the time synchronization of the PCC and the time synchronization of the SCC are the same as in the conventional case, the synchronization of the DL / UL signal of the SCC may be seriously adversely affected.

Meanwhile, in the case of the LCT CC, among the radio resources operating in the LCT CC, radio resources available for transmission / reception of physical uplink / downlink channels and radio resources available for transmission / reception of physical uplink / The resources, as described above, are predetermined. In other words, the LCT CC is not configured to carry physical channels / signals through arbitrary time frequency in arbitrary time resources, but may be configured to transmit the physical channel / Signal should be configured to carry. For example, the physical downlink control channels may be configured only in the first OFDM symbol (s) of the OFDM symbols in the DL subframe, and the PDSCH may include the first OFDM symbol (s) that are likely to be mapped physical downlink control channels. Lt; / RTI > As another example, the CRS (s) corresponding to the antenna port (s) of the eNB are transmitted every subframe in the REs shown in Fig. 9 over the entire band regardless of the DL BW of the eNB. Therefore, when the number of antenna ports of the eNB is 1, the REs indicated by '0' in FIG. 9 are '0', '1', '2' and ' 3 'can not be used for other downlink signal transmission. In addition, there are various constraints on the composition of the LCT CC, and these constraints are greatly increased as the communication system develops. Some of these constraints arise because of the level of communication technology at the time the constraint is created, and there are some constraints that are unnecessary as communication technology develops, and constraints of existing and new technologies for the same purpose It may be present at the same time. As the constraints become so large, the constraints introduced for the development of the communication system are making the wireless resources of the CC ineffective. Therefore, the introduction of NCT CC, which can be constructed according to the simplified constraints rather than the existing constraints, is free from the constraints that are unnecessary according to the development of the communication technology. Since the NCT CC is not constructed according to the constraints of the existing system, it can not be recognized by the UE implemented according to the existing system. Hereinafter, UEs which are implemented according to the existing system and can not support NCT CC are called legacy UEs, and UEs implemented to support NCT CCs are called NCT UEs.

It is considered that NCT CC will be used as SCC in LTE-A system in the future. Since the NCT CC does not consider use by the legacy UE, the legacy UE does not need to perform cell search, cell selection, cell reselection, etc. in the NCT CC. If the NCT CC is not used as a PCC and the NCT CC is used only as an SCC, unnecessary constraints on the SCC can be reduced compared to an existing LCT CC that can be used as a PCC, enabling more efficient use of the CC. However, the time / frequency synchronization of the NCT CC may not coincide with the synchronization of the PCC. Even if the time / frequency synchronization of the NCT CC is obtained once, the time / frequency synchronization may be changed according to the change of the communication environment. An RS in which time synchronization and / or frequency synchronization can be used for tracking is required. An RS is also needed to allow the UE to detect the NCT CC in the neighbor cell search process. CRS can be used for purposes such as time / frequency synchronization of NCT CC and neighbor cell search using NCT CC. The CRS may be configured in the NCT CC in the same manner as in the existing LTE / LTE-A system shown in FIG. 9 and may have less density on the time axis or frequency axis than the conventional LTE / LTE- It may be configured in the NCT CC.

In the present invention, it is proposed that the CRS on the NCT CC is configured to have a lower density on the time axis than the CRS on the LCT CC of the existing LTE / LTE-A system. Accordingly, in the present invention, the NCT CC includes a constraint condition that the CRS is configured in the corresponding CC for every DL subframe, a constraint condition that the CRS is configured in the CC for each antenna port of the eNB, a predetermined number of OFDM It may not satisfy at least one of the constraint conditions that the symbol should be reserved for transmission of the control channel such as the PDCCH over the frequency band of the corresponding CC. For example, on the NCT CC, a CRS may be configured for every predetermined number (> 1) of subframes, not every subframe. Or, on the NCT CC, only the CRS for one antenna port (e.g., antenna port 0) can be configured regardless of the number of antenna ports of the eNB. The CRS of the present invention may not be used for demodulating data unlike the existing CRS shown in FIG. Therefore, instead of the existing CRS used for channel state measurement and demodulation, a tracking RS is newly defined for tracking of time synchronization and / or frequency synchronization, and the tracking RS is added to some subframes and / or some frequency resources on the NCT CC Lt; / RTI > Alternatively, the PDSCH may be configured in the leading OFDM symbols on the NCT CC, the PDCCH may be configured in the existing PDSCH region other than the initial OFDM symbols, or the PDCCH may be configured using some frequency resources. Hereinafter, unlike the existing LTE / LTE-A system, unlike the existing LTE / LTE-A system, the RSs transmitted in some subframes can be used in common by any UE regardless of the name, such as time synchronization and / or frequency synchronization of the NCT CC, RS (common RS, CRS).

13 is a diagram showing an example in which a cross carrier scheduling technique is applied. In particular, in FIG. 13, the number of allocated cells (or component carriers or component carriers) is three and the cross carrier scheduling technique is performed using CIF as described above. Here, it is assumed that the downlink cell # 0 is a downlink main component carrier (i.e., a primary cell, PCell) and the remaining component carriers # 1 and # 2 are subsidiary components (i.e., a secondary cell, SCell).

In the present invention, an effective management method of uplink resources for a main component carrier (primary component carrier, primary cell or PCell) or a subsidiary component carrier (secondary component carrier or secondary cell or SCell) during a carrier aggregation operation I suggest. Hereinafter, the case where the terminal operates by merging two component carriers is explained, but it is obvious that the present invention can also be applied to the case of merging three or more component carriers.

14 is a diagram for explaining the LAA environment.

As shown in FIG. 14, a service environment in which U-LTE or LAA, which is the LTE technology 11 in the existing authorization band and the LTE technology 12 in the unlicensed band which is actively discussed in recent years, have.

If a service environment utilizing the LTE-Unlicensed frequency band is established, there is no need to pay additional costs in order to secure frequency licenses from the viewpoint of the telecommunication service provider. In addition, interference between communication carriers and 3G / And integration problems with the communication network can be easily solved.

Further, a technique such as Carrier Aggregation can integrate the LTE technology 11 in the licensed band and the LTE technology 12 in the unlicensed band, and can contribute to expanding the network capacity in the future. Also, in an environment where asymmetric traffic having more downlink data is generated than uplink data, such an integrated technique can be helpful in providing optimized LTE services according to various needs and environments.

In order to efficiently solve the interference problem in the unlicensed band, it is necessary to introduce a separate coexistence mechanism with other communication systems by reducing the output to minimize the influence on other communication systems used in the unlicensed band Low-power LTE technology is proposed.

In addition, algorithms such as Listen-Before-Talk (LBT) and Dynamic Frequency Selection (DFS), which can detect the output of a base station or the like used by other communication providers and adaptively select a block corresponding to the used frequency, There is also a move to introduce additional technologies.

Since most devices operating in the unlicensed band operate on an LBT basis, the devices perform a clear channel estimation technique that senses the channel before transmitting data.

In case of LTE communication in the unlicensed band, equipment communicating in the unlicensed band with Wi-Fi technology can not demodulate LTE-Unlicensed message or data, judge LTE-Unlicensed message or data as energy, It is possible to perform the interference avoiding operation. That is, if the energy corresponding to the LTE-Unlicensed message or data is less than minus (-) 62 dbm, the Wi-Fi devices can communicate without ignoring the message or data. As a result, in the unlicensed band, a terminal that performs LTE communication may frequently receive interference by Wi-Fi equipment.

Therefore, in order to effectively implement LTE-Unlicensed technology and services, it is necessary to allocate or reserve a specific frequency band for a specific time. However, as described above, there is a problem that it is difficult to efficiently use the LTE-Unlicensed service because the peripheral devices communicating through the unlicensed radio attempt to access based on the energy detection technique.

15 is a diagram illustrating a deployment scenario of a terminal and a base station in an LAA service environment.

In the frequency band targeted by the LAA service environment, the wireless communication distance is not long due to the high frequency characteristics. In consideration of this, the deployment scenario between the terminal and the base station in the environment where the existing LTE-licensed service and the LAA service coexist is the overlay model shown on the left side of FIG. 15 and the overlay model shown in the right side of FIG. or a co-located model.

In the case of the overlay model shown on the left side of FIG. 15, the macro eNB performs wireless communication with the X terminal and the X 'terminal in the macro area 32 using a licensed carrier, and a plurality of RRHs and an X2 interface Lt; / RTI > Each RRH may perform wireless communication with an X terminal or an X 'terminal in a certain area 31 using an unlicensed carrier. In this case, there is no mutual interference between the macro eNB and the RRH. However, in order to use the LAA service as an auxiliary downlink channel of the LTE-licensed service through carrier aggregation, an X2 interface between the macro eNB and the RRH A fast data exchange should be made.

In the case of the co-located model shown on the right-hand side of FIG. 15, the pico / femto eNB can perform wireless communication with the Y terminal simultaneously using the authorized carrier and the unauthorized carrier. However, the use of the LTE service and the LAA service together is considered in the downlink data transmission. In this case, coverage for LTE service and coverage for LAA service may differ depending on frequency band, transmission power, and the like.

A terminal according to an embodiment of the present invention can be implemented by various types of wireless communication devices or computing devices that are guaranteed to be portable and mobility.

The base station according to the embodiment of the present invention controls and manages a cell (for example, a macro cell, a femtocell, a picocell, etc.) corresponding to a service area and transmits a signal, channel designation, channel monitoring, Can be performed.

16 is a block diagram showing a configuration of a terminal and a base station according to an embodiment of the present invention.

As shown, a terminal 100 according to an embodiment of the present invention may include a processor 110, a communication module 120, a memory 130, a user interface unit 140, and a display unit 150 have.

First, the processor 110 may execute various commands or programs, and may process data inside the terminal 100. [ In addition, the processor 100 can control the entire operation including each unit of the terminal 100, and can control data transmission / reception between the units.

Next, the communication module 120 may be an integrated module that performs mobile communication using a mobile communication network and wireless LAN connection using a wireless LAN. To this end, the communication module 120 may include a plurality of network interface cards such as the cellular communication interface cards 121 and 122 and the wireless LAN interface card 123, either internally or externally. In FIG. 16, the communication module 120 is shown as an integrated integrated module, but each network interface card may be independently arranged according to the circuit configuration or use, unlike FIG.

The cellular communication interface card 121 according to the first frequency band transmits and receives a radio signal with at least one of the base station 200, the external device, and the server using the mobile communication network, Band cellular communication service. Here, the wireless signal may include various types of data or information such as a voice call signal, a video call signal, or a text / multimedia message.

According to an embodiment of the present invention, the cellular communication interface card 121 by the first frequency band may include at least one NIC module using the LTE-Licensed frequency band. According to an embodiment of the present invention, at least one NIC module performs cellular communication with at least one of the base station 200, the external device, and the server independently in accordance with the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module . The cellular communication interface card 121 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

The cellular communication interface card 122 in the second frequency band transmits and receives a radio signal to and from a base station 200, an external device, and a server using a mobile communication network, Band cellular communication service. According to an embodiment of the present invention, the cellular communication interface card 122 by the second frequency band may include at least one NIC module using the LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module performs cellular communication with at least one of the base station 200, the external device, and the server independently in accordance with the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module . The cellular communication interface card 122 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

The wireless LAN interface card 123 according to the second frequency band transmits and receives a radio signal to at least one of the base station 200, the external device, and the server through the wireless LAN connection, Band wireless LAN service. According to an embodiment of the present invention, the wireless LAN interface card 123 according to the second frequency band may include at least one NIC module using the wireless LAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module performs wireless communication with at least one of the base station 200, the external device, and the server independently in accordance with a wireless LAN standard or protocol of a frequency band supported by the corresponding NIC module . The wireless LAN interface card 123 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

According to an embodiment of the present invention, the processor 110 transmits information on whether or not the wireless LAN communication service of the second frequency band is available through the cellular communication channel of the first frequency band with the base station 200, Information on the period of time. Here, the information on the predetermined period is information set for receiving the downlink data from the base station 200 through the cellular communication channel of the second frequency band.

In addition, according to an embodiment of the present invention, since the base station 200 supports a wireless LAN communication service, the processor 110 can receive a predetermined signal from the base station 200 through a wireless LAN communication channel of a second frequency band And receives the base station coexistence message including information on the period.

In addition, according to an embodiment of the present invention, the processor 110 may be configured to transmit, in response to the received base station coexistence message, The terminal transmits a terminal coexistence message including information on a predetermined period according to a standard or protocol specified in the wireless LAN communication service of the second frequency band.

Also, according to an embodiment of the present invention, the processor 110 receives downlink data from the base station 200 for a predetermined period through a cellular communication channel of a second frequency band.

Next, the memory 130 stores a control program used in the terminal 100 and various data corresponding thereto. The control program may include a predetermined program required for the terminal 100 to perform wireless communication with at least one of the base station 200, the external device, and the server.

Next, the user interface 140 includes various types of input / output means provided in the terminal 100. That is, the user interface 140 can receive user input using various input means, and the processor 110 can control the terminal 100 based on the received user input. In addition, the user interface 140 may perform output based on instructions of the processor 110 using various output means.

Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects such as a content executed by the processor 110 or a user interface based on a control command of the processor 110. [

16, a base station 200 according to an embodiment of the present invention may include a processor 210, a communication module 220, and a memory 230. In addition,

First, the processor 210 may execute various commands or programs and may process data within the base station 200. In addition, the processor 210 can control the entire operation including each unit of the base station 200, and can control data transmission / reception between the units.

Next, the communication module 220 may be an integrated module for performing mobile communication using a mobile communication network and wireless LAN connection using a wireless LAN, such as the communication module 120 of the terminal 100 described above. To this end, the communication module 120 may include a plurality of network interface cards, such as the cellular communication interface cards 221 and 222 and the wireless LAN interface card 223, either internally or externally. In Fig. 16, the communication module 220 is shown as an integrated integration module, but each network interface card may be independently arranged according to the circuit configuration or use, unlike Fig.

The cellular communication interface card 221 according to the first frequency band transmits and receives a radio signal to at least one of the terminal 100, the external device, and the server using the mobile communication network, And provides cellular communication service by one frequency band. Here, the wireless signal may include various types of data or information such as a voice call signal, a video call signal, or a text / multimedia message.

According to an embodiment of the present invention, the cellular communication interface card 221 by the first frequency band may include at least one NIC module using the LTE-Licensed frequency band. According to an embodiment of the present invention, the at least one NIC module can perform cellular communication with at least one of the terminal 100, the external device, and the server independently according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module. Can be performed. The cellular communication interface card 221 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200.

The cellular communication interface card 222 according to the second frequency band transmits and receives a radio signal to at least one of the terminal 100, the external device, and the server using the mobile communication network, And provides a cellular communication service by two frequency bands. According to an embodiment of the present invention, the cellular communication interface card 222 by the second frequency band may include at least one NIC module using the LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, the at least one NIC module can perform cellular communication with at least one of the terminal 100, the external device, and the server independently according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module. Can be performed. The cellular communication interface card 222 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200. [

The wireless LAN interface card 223 according to the second frequency band transmits and receives a radio signal with at least one of the terminal 100, the external device and the server through the wireless LAN connection, and based on the command of the processor 210 And provides a wireless LAN service by a second frequency band. According to an embodiment of the present invention, the wireless LAN interface card 223 according to the second frequency band may include at least one NIC module using the wireless LAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module independently communicates with at least one of the terminal 100, the external device, and the server in accordance with a wireless LAN standard or protocol of a frequency band supported by the corresponding NIC module Can be performed. The wireless LAN interface card 223 can operate only one NIC module at a time or operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200. [

According to an embodiment of the present invention, the processor 210 transmits information on whether or not the wireless LAN communication service of the second frequency band is available through the cellular communication channel of the first frequency band with the terminal 100, Information on the period of time. Here, the information on the predetermined period is information set for transmitting the downlink data to the terminal 100 through the cellular communication channel of the second frequency band.

In addition, according to an embodiment of the present invention, the processor 210 may be a peripheral terminal capable of communicating with the base station 200 through the terminal 100 and the wireless LAN communication service of the second frequency band, And transmits the base station coexistence message including information on a predetermined period according to a standard or protocol defined in the wireless LAN communication service to the terminal 100 for a predetermined period on the cellular communication channel of the second frequency band, .

In addition, according to an embodiment of the present invention, since the terminal 100 supports the wireless LAN communication service, the processor 210 transmits the base station coexistence message Lt; RTI ID = 0.0 > coexistence < / RTI > Here, the terminal coexistence message includes information on a predetermined period.

The terminal 100 and the base station 200 shown in FIG. 16 are block diagrams according to an embodiment of the present invention. Blocks that are separately displayed are logically distinguished from elements of a device. Thus, the elements of the device described above can be mounted as one chip or as a plurality of chips depending on the design of the device. In addition, in the embodiment of the present invention, some components of the terminal 100, such as the user interface 140 and the display unit 150, may be optionally provided in the terminal 100. In addition, in the embodiment of the present invention, the user interface 140, the display unit 150, and the like may be additionally provided to the base station 200 as needed.

Below is a description of the LBT method in Licensed Assisted Access considered in LTE.

First, the channel access method on the license-exempted band can be classified into four methods.

- Category 1: No LBT

- Tx. LBT procedure by entity is not performed.

- Category 2: LBT without random back-off

- Tx. The time interval during which the channel is idle is determined before the entity transmits.

- Category 3: LBT with random back-off with a contention window of fixed size

- A LBT method that performs a random back-off with a contention window with a fixed size. The Tx entity has a random N value in one contention window, sets the contention window by the minimum and maximum values of N , The contention window size is fixed. A random N value is used in the LBT procedure to determine the time interval during which the channel is idle before the Tx entity transmits on the channel.

- Category 4: LBT with random back-off with a contention window of variable size

- A LBT method that performs a random back-off with a contention window with a variable size. The Tx entity has a random N value in one contention window, sets the contention window by the minimum and maximum values of N , and Tx An entity can change its contention window size when generating a random N value. A random N value is used in the LBT procedure to determine the time interval during which the channel is idle before the Tx entity transmits on the channel.

The category 4 LBT considered in licensed assisted access (LAA) to ensure fair channel access with WiFi is:

The contention window size (CWS) in the LAA is variable as a dynamic variable backoff or a semi-static backoff between the X and Y ECCA slots. More specifically:

One example of a change in CW may be an exponential back-off.

The X and Y values are configurable parameters.

Two methods can be considered to adjust the CW for the PDSCH. First, there may be a method of adjusting the CW based on the feedback / report (for example, HARQ Ack / Nack) of the UE. Next, there may be a method of adjusting the CW based on the sensing of the eNB.

The minimum extended clear channel assessment (CCA) is considered to be less than 20us.

* Initial CCA (ICCA) can be configurable as a value comparable to defer periods such as DIFS or AIFS used in WiFi.

When the ECCA count-dwon is interrupted, one defer period is applied after the channel becomes idle, and does not perform ECCA count down during the defer period.

* The Defer period is configurable and can be configured to match the defer period of WiFi, eg DIFS or AIFS.

An Initial CCA is performed to transmit the DL transmission burst when the eNB fails to complete transmission of a signal or channel even though the random backoff counter reaches zero in the backoff procedure

The adaptability of the energy detection reference value can be applied to the above LBT procedure. The defer period is defined as the minimum time that one node must wait after the channel becomes idle before transmission. That is, if the channel is idle for a time interval that is not less than the defer interval, one node performs the transmission.

A flow chart for explaining the LBT procedure is shown in FIGS. 17 and 18. FIG.

Below is a description of parameter setting and additional LBT catetory 4 operation during Listen before Talk (LBT) operation in LAA.

For LBT operation in LAA, the slot size of ECCA is 9 μs, and the actual sensing time is at least 4 μs.

For operation in the LBT category 4 method for PDSCH, one defer period consists of 16μs duration and n consecutive CCA slots. Here, n denotes a positive integer, CCA slot duration is 9 μs, and the number of slots in the defer period can be set differently according to different QoS classes. The backoff counter does not count down during the 16 μs duration at the beginning of the defer period, and the back off counter can be decremented by 1 at the end of the defer period when all n slots are observed as idle. If the backoff counter reaches zero after decrementing, the node continues the ECCA procedure by performing a CCA check during at least one slot without immediately transmitting immediately. The defer period may also be interrupted if the channel is observed to be busy at some other interval.

Hereinafter, a channel access procedure for transmitting the PDSCH will be further described.

The eNB may transmit a transmisson containing the PDSCH on the channel on which the LAA Scell (s) transmission is performed after the channel is idle for defer duration (Td) and after the random backoff counter (N) has become zero . Where counter N is adjusted by sensing the channel for additional slot duration (s) according to the procedure below.

1) N = Ninit. Ninit is a random number from a uniformly distributed value between 0 and CWp.

2) If N> 0 and the eNB chooses to decrease the counter, set N = N-1.

3) It senses the channel during one additional slot duration, and if it idle during that additional slot duration, go to step 4), otherwise go to step 5).

4) If N = 0, stop; otherwise go to step 2).

5) It senses the channel during one additional defer duration (Td) interval.

6) If the channel is sensed as idle during slot intervals of the additional defer duration (Td), go to step 2), otherwise go to step 5).

If the eNB has not transmitted a transmission including PDSCH on the channel on which the LAA Scell (s) transmission is performed after step 4 in the previous step, the eNB will notify the UE that at least the channel idle during the slot periods of the additional defer duration (Td) It is possible to transmit the transmission including the PDSCH in the corresponding channel.

Here, the defer duration (Td) is composed of consecutive slot durations that are directly followed by 16us (Tf), each slot duration (Tsi) is 9us, and Tf is one idle slot duration Tsi at the beginning of Tf .

* The mp value is set according to the channel access priority class according to table X-1 below.

Table X-1. Channel Access Priority Class

If the eNB senses a channel for one slot duration and the power detected by the eNB for at least 4us within that slot duration is less than or equal to X_Threshold, then one slot duration (Tsi) is considered idle. Otherwise, the slot duration (Tsi) is considered busy.

조건을 만족하도록 Contention window(CW)는 설정되며, CWmin,p와 CWmax,p는 random backoff counter N에 관계된 절차인 단계 1) 동안 선택된다. 그리고 CW의 조정방법에 대해서는 아래 발명의 상세 내용에 따로 설명한다. As for the setting of the Contention window, according to the CWmin, p and CWmax, p set according to the channel access priority class

The contention window (CW) is set to satisfy the condition, and CWmin, p and CWmax, p are selected during step 1), which is a procedure related to the random backoff counter N. The method of adjusting the CW will be described in detail in the following description of the invention.

The adjustment of X_Threshold is based on case and regulation coexisting with other technology as shown in table Y-1 below, and the energy detection threshold (X_Threshold) is set by distinguishing the case where Wi-Fi is absent.

Table Y-1. Energy Detection Thershold adaptation rule

The value of Tmax in Table Y-1 is shown in the following equation.

In addition, T_mcot, p is set according to the channel access priority class according to Table X-1, and the eNB does not continuously transmit T_mcot, p over a single channel on which LAA Scell (s) transmission is performed Should be. For the priority class p = 3 and p = 4, we set T_mcot, p = 10ms for the case where it is possible to guarantee the absence of other technology using the license term based on the long term at the regulation level. T_mcot, p = 8ms.

The present invention relates to a method for accessing a channel at the time of carrier sensing and is a method for adaptively adjusting a contention window size (hereinafter referred to as CWS).

There is a method of adjusting the CWS based on the UE feedback transmitted from the UE as a method of adjusting the CWS. In the following description of the present invention, a method of adaptively adjusting CWS according to ACK / NACK / DTX considered as HARQ-ACK response as UE feedback can be considered as feedback of the UE in consideration of HARQ-ACK response and CQI / PMI / Will be described.

The following method can be considered as one embodiment of a method of adjusting CWS based on an ACK / NACK of an HARQ-ACK response in a method of adaptively adjusting CWS in the present invention.

First, in case of contention window size (CWS) adjustment based on HARQ-ACKs, sets of HARQ-ACK feedback values to be considered are defined as follows. The set of HARQ-ACKs feedback values considered for CWS coordination is decoded at the time the CWS is determined and corresponds to the available HARQ-ACKs.

The following methods can be considered as the method of adjusting the CWS based on the set of the HARQ-ACK feedback values. For the options 1, 2, 3 and alt 1, 2 and 3, the corresponding combination is considered as a method of adjusting the CWS .

Option 1: Increase the contention window size (CWS) if all HARQ-ACK feedback values for a single subframe are NACK, otherwise reset CWS to the minimum value. Where a single subframe may be the first or last DL subframe of the last DL transmission burst. In calculating the set of the HARQ-ACK feedback value, the HARQ-ACK feedback may be all the available subframes of the HARQ-ACK feedback of the last available DL transmission burst.

Option 2: Increase the contention window size (CWS) if at least one of the HARQ-ACK feedback values for the subframe is a NACK, and otherwise reset the CWS to the minimum value. Where a single subframe may be the first or last DL subframe of the last DL transmission burst. In calculating the set of the HARQ-ACK feedback value, the HARQ-ACK feedback may be all the available subframes of the HARQ-ACK feedback of the last available DL transmission burst.

Option 3: Increase the CWS when the NACK of the HARQ-ACK feedback value is at least Z% within the predetermined window, otherwise reset the CWS to the minimum value. Where a single subframe may be the first or last DL subframe of the last DL transmission burst. In calculating the set of the HARQ-ACK feedback value, the HARQ-ACK feedback may be all the available subframes of the HARQ-ACK feedback of the last available DL transmission burst.

In addition, if at least one of the following conditions is satisfied, the CWS is reset to the minimum value.

Alt 1: where maximum CWS is used for K consecutive eCCAs for transmission, where K may be 1, 2, or 3. The K choices may also be selected by the base station, and the values may be selected within the values {1, ..., 8}.

Alt 2: No DL transmission by eNB during at least T interval

In an exemplary embodiment of the present invention, a reference time window for setting a reference HARQ-ACK feedback value for increasing CWS may be a regular subframe or a partial subframe in a single subframe of the last DL transmission burst. In the case of a partial subframe, since the number of UEs to which a base station can be served may be limited, a set of HARQ-ACK feedback values is set based on a HARQ-ACK feedback value of a UE (s) corresponding to a regular subframe, Thereby allowing the base station to perform efficient coordination of the CWS due to collision or interference.

The method that can be applied when increasing CWS in option-1, option-2, and option-3 is to set CWS to increase to double, or to increase it exponentially between CW_min and CW_max, or to maximize CWS Can all be considered.

As another embodiment of the present invention, a method of adjusting CWS in consideration of not only ACK and NACK but also DTX as HARQ-ACK response transmitted from a terminal when the CWS is adjusted will be described.

First, a DL or UL transmission of a carrier of each license-exempt band is performed through a control channel transmitted on each license-exempt band carrier, for example, a PDCCH and an EPDCCH during self-carrier scheduling, The ACK / NACK / DTX used in the current LTE may exist as the HARQ feedback that the UE can transmit. The following is a description of a procedure of HARQ-ACK in an FDD having one or more serving cells, in which a HARQ-ACK is transmitted in a PUCCH format 1b with channel selection as a PUCCH format transmitted in PCell. The following table is an example to illustrate that there is a mechanism to allow DTX to be transmitted or DTX to be recognized by the base station as HARQ-ACK respose created in the standard 3GPP TS36.213v12.6.0. Here, DTX is one of methods for the UE to notify the BS when the UE fails to decode the PDCCH / EPDCCH despite transmitting PDCCH / EPDCCH, which is a control channel including scheduling information, to the UE.

3GPP TS36.213v12.6.0

10.1.2.2 FDD HARQ-ACK procedures for more than one configured serving cell

...

10.1.2.2.1 PUCCH format 1b with channel selection HARQ-ACK procedure

...

Table 10.1.2.2.1-1: Mapping of Transport Block and Serving Cell to HARQ-ACK (j) for PUCCH format 1b HARQ-ACK channel selection

Table 10.1.2.2.1-3: Transmission of Format 1b HARQ-ACK channel selection for A = 2

Table 10.1.2.2.1-4: Transmission of Format 1b HARQ-ACK channel selection for A = 3

Table 10.1.2.2.1-5: Transmission of Format 1b HARQ-ACK channel selection for A = 4

First, in the case of contention window size (CWS) adjustment based on HARQ-ACKs, sets of HARQ-ACK feedback values to be considered can be defined as follows. The set of HARQ-ACKs feedback values considered for CWS coordination is decoded at the time the CWS is determined and corresponds to the available HARQ-ACKs.

A-1, A-2, A-3, A-4 and B-1, B-2, and A-4 can be considered as methods for adjusting CWS based on a set of HARQ- For B-3, the combination can be considered as a way of adjusting the CWS.

Method A-1: When all HARQ-ACK feedback values for a single / multiple subframe are NACK, or when all HARQ-ACK feedback values With DTX If the case is considered, or and all the HARQ-ACK feedback value to increase the contention window size (CWS) in the case of NACK / DTX, if not, to reset the CWS to the minimum value. Here, a single subframe may be the first or last DL subframe of the last DL transmission burst. In case of multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmission burst, and a multiple subframe . For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

Method A-2: Increase the contention window size (CWS) if at least one of the HARQ-ACK feedback values for the single / multiple subframe is NACK or DTX, otherwise, reset the CWS to the minimum value. Here, a single subframe may be the first or last DL subframe of the last DL transmission burst. In case of multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmission burst, and a multiple subframe . For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

Method A-3: CWS is increased if NACK or DTX of the HARQ-ACK feedback value is at least Z% within the predetermined window, otherwise CWS is reset to the minimum value. The window to be set here may be a single subframe, which may be the first or last DL subframe of the last DL transmission burst. If it is set to multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmsision burst, Or may be a multiple subframe. For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Or a predetermined window can be set by the base station. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

Method A-4: All HARQ-ACK feedback values for single / multiple subframes If DTX is considered, even decoding of PDCCH / EPDCCH transmitted by the base station is considered to be a failure of PDCCH / EPDCCH decoding due to interference due to transmission from other nodes due to collision, Here, as a method of increasing CWS, a method of increasing CWS to double, or exponentially increasing CW_min and CW_max, or increasing CWS to a maximum value may all be considered. Otherwise, all HARQ-ACK feedback values With DTX If that is not considered to include in the manner described in Method A-1, A-2, A-3 to increase the CWS or a CWS or reset to its minimum value. Here, a single subframe may be the first or last DL subframe of the last DL transmission burst. In case of multiple subframes, it may be a multiple subframe starting from the beginning of the last DL tranmission burst, and a multiple subframe . For example, when considering two multiple subframes, it may be the first two partial subframes of the last DL transmission burst, or a regular subframe of 1 ms length and a regular subframe of length 1 ms. Considering two multiple subframes as the last DL subframes A regular subframe of 1 ms in length and a partial subframe or a regular subframe of 1 ms in length may be used. Also, in calculating the set of HARQ-ACK feedback values, HARQ-ACK feedback as a multiple subframe may be all subframes available for HARQ-ACK feedback of the last available DL transmission burst.

In addition, if at least one of the following conditions is satisfied, the CWS is reset to the minimum value.

Method B-1: Where maximum CWS is used for K consecutive eCCAs for transmission, where K may be 1, 2, or 3. The K choices may also be selected by the base station, and the values may be selected within the values {1, ..., 8}.

Method B-2: If there is no DL transmission by the eNB during at least T interval

Method B-3: where maximun HARQ retransimssion is used during K consecutive eCCAs, where K may be 1, 2, or 3. The K choices may also be selected by the base station, and the values may be selected within the values {1, ..., 8}.

The methods that can be applied when increasing CWS in methods A-1, A-2, A-3, and A-4 include setting CWS to increase to double, exponentially increasing CW_min to CW_max, To a maximum value can all be considered.

Next, in cross-carrier scheduling,

If DL transmission to unlicensed carriers is due to cross-carrier scheduling from another license-exempt band, unlicensed carrier, CWS adjustment is performed using the same method as in self-carrier scheduling. Since the control channel is transmitted on unlicensed carriers as in self-carrier scheduling, the self-carrier scheduling and HARQ-ACK response (ACK, NACK, DTX) to be.

If DL transmission to unlicensed carriers is due to cross-carrier scheduling from the licensed band, ie, licensed carrier, transmission of the PDCCH / EPDCCH to perform DL transmission is transmitted from the license band. In case of DTX feedback for recognizing the terminal as a HARQ response of the terminal, it is used to determine the decoding state of the terminal for the control channel transmitted on the license band. Therefore, adaptive control of the CWS considered as a method for accessing the channel in the license- It may not help to do so. Therefore, when cross-scheduling from the license band, the CWS adjustment method considering DTX is not used as the HARQ-ACK response from the terminal, and only ACK and NACK are used as the HARQ-ACK reponse for DL transmission on the license- Based on which the method of adjusting the CWS can be used.

Considering ACK, NACK and ACK, NACK, and DTX as HARQ-ACK response in the present invention, DL transmission bursts transmitted from a base station are scheduled for a single UE and scheduling for multiple UEs The method of adjusting CWS considering feedback from one UE and the method of adjusting CWS considering feeback from multiple UEs can all be considered.

The HARQ-ACK response transmitted from the UE is set to be transmitted through the PUCCH or PUSCH on the PCell of the license band. Of course, the present invention can be applied to the transmission of the HARQ-ACK response through the PUCCH or PUSCH on the unlicensed band in the case where the uplink transmission on the license-exempt band is allowed.

The present invention relates to a method for an efficient channel access procedure through modification of the channel access procedure described above.

The following embodiment of the present invention will be described as an embodiment for performing an efficient channel access procedure through modification of the channel access procedure for transmitting the PDSCH described above.

When the Ninit value of the random backoff counter is 1 and the Ninit value of the random backoff counter is 0, when the channel access procedure for transmitting the PDSCH described above is followed, the number of slots sensing the channel is the same Can be set. If the channel is idle at more than one duration (Td) and one slot duration (Tsi), the defer duration and the random backoff counter The channel sensing interval is set according to the intention of the Ninit value to sense the channel during one slot duration by the extraction value Ninit = 1, but when the Ninit value is 0, the channel access procedure for transmitting the PDSCH described above is performed If the channel idle at more than the defer duration (Td) and zero slot duration (Tsi), the intention of the Ninit value to sense the channel during the slot duration of 0 by Ninit = 0, (Td) and one slot duration (Tsi) by sensing the channel during one slot duration according to step 3) ensuring that the channel sensing interval is set to a value that does not fit the intention of the Ninit value.

In the present invention, when the N value is 0, if the slot durations of the defer duration (Td) are idle, it is possible to instantaneously transmit the transmission including the PDSCH in the channel where the LAA Scell (s) transmission is performed, The channel access procedure is performed by differentiating the number of slot durations (Tsi) sensed in the case of setting Y (Y + 1) and Y (Ninit). (Y + 1) is selected as the Ninit value when the channel on the LAA Scell (s) to be transmitted is idle, channel sensing (Y + 1) is performed for defer duration (Td) + And transmits the transmission (s) including the PDSCH. When Y is extracted as the Ninit value, channel sensing is performed during defer duration (Td) + Y slot duration (Tsi) To transmit the transmitted transmission (s). Where Y can be zero and can be a natural number greater than or equal to zero.

FIG. 19 illustrates an embodiment of the present invention as described above. As an example of a case where a channel is idle, channel priority class 3 is used as a defer duration, and 19- (a) and channel priority Figure 3 shows the case of 19- (b) using class 3 and extracting Ninit = 0.

As another embodiment, when the channel is busy while decreasing the N value to perform the set random backoff, if N is set to a value set by the Ninit value and then it is determined that the channel is busy, (Td), and when the channel is continuously busy during the Td interval, the channel sensing is continuously performed for Td, and is set in units of Tsi according to the N value for random backoff The number of total idle slots should be set to the number of Tsi according to Ninit.

If the Ninit value of the random backoff counter is 2 and the Ninit value of the random backoff counter is 1, if the channel access procedure for transmitting the PDSCH described above is followed, the number of slots sensing the channel is the same Can be set. If the channel is idle at defer duration (Td) and busy at one of the two slot durations (Tsi), then 2 defer duration The channel sensing interval is set according to the intention of the Ninit value to detect the channel during the 2 slot duration (Tsi) interval by the extraction value Ninit = 2 of the random backoff counter. However, when 1 is taken as the Ninit value, If the channel is idle at defer duration (Td) and busy at one slot duration (Tsi), then one deinterleaver with two defer durations and an extracted value of the random backoff counter Ninit = 1 During the slot duration, the channel sensing interval is not set according to the intention of the Ninit value to sense the channel, and according to step 3, the channel for one additional slot duration interval is sensed, It is set to sense the channel during the duration (Td) and two slot duration (Tsi), and the channel sensing interval is set the same as when the Ninit value is set to 2. This means that the channel sensing Section is set.

In the present invention, when the N value is 0, if the slot durations of the defer duration (Td) are idle, it is possible to instantaneously transmit the transmission including the PDSCH in the channel where the LAA Scell (s) transmission is performed, The channel access procedure is performed by differentiating the number of slot durations (Tsi) sensed in the case of setting Y (Y + 1) and Y (Ninit). (Y + 1) is selected as the Ninit value when the channel on the LAA Scell (s) to be transmitted is idle, channel sensing (Y + 1) is performed for defer duration (Td) + And transmits the transmission (s) including the PDSCH. When Y is extracted as the Ninit value, channel sensing is performed during defer duration (Td) + Y slot duration (Tsi) To transmit the transmitted transmission (s). Where Y can be zero and can be a natural number greater than or equal to zero.

FIG. 20 shows an example of a case where a channel is busy in one slot as an embodiment of the present invention described above. In this case, channel priority class 3 is used as a defer duration, 20- (a) extracted as Ninit = 2, (B), where Ninit = 1 is extracted.

The following is the operation of the base station and the terminal regarding the UL LBT operation.

The following describes a method for performing UL LBT for UL transmission in an LAA cell.

As one embodiment of a method of performing LBT for UL transmission in an LAA cell, there may be a case where UL transmission is successively performed next to DL transmission as shown in FIG. In FIG. 21, the last subframe of the LAA burst may be a full subframe (eg 1 ms, 14 OFDM symbols) or an ending partial subframe (eg, the number of occupied OFDM symbols is {3, 6, 9, 10, 11 12} Partial OFA symbols constituting the initial subframe (eg, 1 ms, 14 OFDM symbols) or OFA symbols smaller than 14 (eg 7 OFDM symbols) in the initial partial subframe, subframe.

Table below. B-1 is an occupied OFDM signal from a subframe configuration for a LAA field transmitted via common control signaling (i. E., PDCCH with DCI scrambled by CC-RNTI) as described in section 13 in 3GPP TS 36.213 v13.0.0. Represents configuration information about the number of symbols.

The common control signaling described in the present invention may mean a PDCCH having a DCI scrambled by a CC-RNTI as an example.

<Table-B-1. Subframe configuration for LAA in current and next subframe>

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, when the base station transmits UL grant in subframe n and UL transmission is performed in subframe n + 4, as shown in FIG. 21, The detetion of the common control signaling from the end of the on-going DL transmission burst transmitting the PDSCH to the SF # (n + 2) or the last SF # (n + 3) preceding the subframe (UE1) can recognize that the SF # (n + 3) is the last SF of the on-going DL transmission burst, it is determined that the transmission of the UL is consecutively performed next to the DL transmitted subframe, Since the LBT is performed once in the DL for the transmission of the UL grant, the UL transmission intended for the UL grant may be transmitted without the UL LBT, or the channel may be transmitted through only the single sensing interval If it is idle, UL transmission may be performed, or UL transmission may be performed after UL LBT with back-off. The common control signaling described above transmits the configuration information of the current subframe and the configuration information of the next subframe as information transmitted by the base station. The terminal detects the configuration information of the next subframe and the configuration of the current subframe Information and last subframe configuration and whether the configuration of the last subframe of the DL transmission burst is a full subframe or 14 OFDM symbols or the number of occupied OFDM symbols as an ending partial subframe is {3, 6, 9 , 10, 11 12}.

However, if DL transmission in SF # (n + 3) is not full subframe as a behavior of the terminal and DL grant in SF # (n + 3) is not equal to DL subframe, the UL subframe boundary UE are (previously received scheduling) to: 1) perform the LBT once in the DL transmission when the UL grant hayeoteumeuro additionally for the UL transmission intended by the UL grant the UE to transmit or without UL LBT 2) back- If so, perform the UL LBT that off, or 3) single reporting interval CCA is idle Ann Wu rest of the UL subframe boundary by transmitting a reservation signal (s), or 4) UL subframe boundary just before reporting the single interval CCA idle UL If the transmission is not performed and a single interval interval busy, the UL transmission associated with the UL grant can be set not to be transmitted . In this case, the UE can guarantee transmission in the UL subframe boundary from the viewpoint of UL transmission.

As another embodiment of the method of performing LBT for UL transmission in the LAA cell, when UL grant is received in SF # n as a behavior of the UE and DL transmission in SF # (n + 3) is Full subframe UL transmission at the UL subframe boundary can not be guaranteed. The UL DL transmission of the UE scheduled to be performed next to the last DL subframe is intended to be performed only when the DL subframe is configured as a full subframe since at least the switching time of the DL- The following two methods should be considered. First, from the viewpoint that the UL transmission at the UL subframe boundary must always be matched, a method of receiving UL grant in SF # n and not DL scheduling in SF # (n + 3) to Full subframe is 1) UL transmission in SF # n + 4 is intended to transmit the UL transmission in SF # n + 4, and DL-UL switching time and UL LBT are performed before UL subframe boundary for DL transmission in SF # n + 3 It is possible to schedule transmission to an ending partial subframe so as to guarantee an interval for performing UL LBT . Or 2) DL transmission in SF # (n + 3) is transmitted through common control signaling in a full subframe. If transmission of UL grant is performed in SF # n, the BS determines that the last OFDM symbol is empty As shown in FIG. All of these methods may degrade base station scheduling flexibility.

As another embodiment of a method of performing LBT for UL transmission in the LAA cell, when UL grant is received in SF # n as a behavior of the UE and DL transmission in SF # (n + 3) is Full subframe, UL subframe Since the transmission of UL transmission at the boundary can not be guaranteed, the UL transmission is set to start from symbol # 1 or symbol # 2 when the SC-FDMA symbol index starts from behind one SC-FDMA symbol instead of UL subframe boundary. . The UE needs to guarantee at least the switching time of the DL-UL even if it is directly transmitted without performing the UL LBT for the UL transmission as the No UL LBT option. Therefore, when assuming UL transmission in the SC-FDMA symbol unit, FDMA symbol may be required, or a UL-LBT with a DL-UL switching time and a single sensing interval in at least one symbol, or a contention window size capable of performing back-off in one SC- That is, UL LBT when the number of slots of the CCA is 3 or 4, and the UE can perform UL transmission from the second SC-FDMA symbol. Alternatively, a method of performing UL LBT with back-off using two SC-FDMA symbols may be considered. In this case, the UL transmission may be transmitted from the third SC-FDMA symbol. In case of performing UL LBT through one or two SC-FDMA symbols, UL transmission in the UE performs rate matching considering the case where the first SC-FDMA symbol is missing, or UL transmission performs the first two The rate matching can be performed considering the case where the SC-FDMA symbol is missing.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, the UE transmits a UL grant in the UL LBT and the SF #n, and performs SF # n + 4 in the UL # And the common control signaling in SF # n + 3 to determine whether the last SF of the corresponding on-going DL burst is a full subframe or an ending partial subframe, the UL LBT It is possible to set whether the viewpoint is to be performed before the UL subframe boundary or within the UL subframe and rate-matching for transmission of the PUSCH to be transmitted on the UL subframe may be performed using implicit signaling by common control signaling have.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, there may be ambiguity of the UE at the time of the LBT for UL transmission in the position of the UE scheduled in SF # n + 5 in FIG. The UE scheduled to SF # n + 5 must perform transmission in the subframe boundary of SF # n + 5 in view of UL transmission at the UL subframe boundary. Therefore, the UE scheduled to transmit UL at SF # n + The last one or two SC-FDMA symbols of the PUSCH transmission in SF # n + 4 should be left empty as shown in Figure 21- (a) so that other UEs can perform LBT. However, when the DL transmission in SF # n + 3 is configured as a full subframe, since there is no time interval for performing UL LBT between UL subframe boundaries after DL subframe in SF # n + 3, Or the UL LBT should be performed using two SC-FDMA symbols. In the case of the UL transmission to be transmitted to the SF # n + 4 under the scenario of FIG. 22, since the subframe configuration in SF # n + 3 must be made only by the configuration of the full subframe, the first one or two SC- The UL LBT must be performed using the FDMA symbol. Therefore, since the scheduling can be performed independently from the UE in the UE's viewpoint, there may be ambiliency as described above regarding the point at which UL LBT is to be performed. Therefore, when UL LBT synchronization is required to maintain multiuser multiplexing between UEs, some UEs perform UL transmission at the UL subframe boundary by performing LBT ahead of UL subframe boundary, and the first one or two SC-FDMA the UEs attempting to perform the UL LBT in the UL subframe and performing the UL transmission may receive the first UL subframe of the UL subframe due to the UL transmission at the UL subframe boundary transmitted by the UEs that have performed UL LBT before the preceding UL subframe boundary, there is a high possibility that the channel is busy in the symbols, so that the UL transmission can not be performed in the SF # n + 4 even though the UL grant is received in the SF # n. Therefore, when transmitting an UL grant, signaling for the UL LBT at the terminal (ie, before the UL subframe boundary or in the first one or two SC-FDMA symbols in the UL subframe) is included in the UL grant. , Or signaling to the point at which UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to difference in UL LBT execution time between terminals and allowing multi-user multiplexing .

As another embodiment of the method for performing the LBT for the UL transmission in the LAA cell, when the UL LBT point set to one is used, because the specific terminal fails to detect the end of the common control signaling in the last SF # n + Even when the configuration information of the DL subframe is not known, the UL LBT time points between different UEs are different, and interference between the UEs is generated, thereby increasing the probability of LBT failure. Therefore, when transmitting an UL grant, signaling for the UL LBT at the terminal (ie, before the UL subframe boundary or in the first one or two SC-FDMA symbols in the UL subframe) is included in the UL grant. , Or signaling to the point at which UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to difference in UL LBT execution time between terminals and allowing multi-user multiplexing .

The following is a description of a method for performing uplink transmission without UL LBT, which is similar to a Wi-Fi ACK transmission immediately after DL 16s, and a UL LBT operation method for continuous UL transmission after DL transmission to an LAA cell .

In another embodiment of the method for performing LBT for UL transmission in the LAA cell, when the base station transmits UL grant in subframe n and UL transmission in subframe n + 4, as shown in FIG. 21, In the SF # (n + 3), a UE is scheduled to receive PDSCH as a DL transmission for an UE (eg, UE1) in the DL transmission from the eNB through decoding of the PDCCH / EPDCCH Or when an arbitrary UE recognizes that it is scheduled through PDCCH / EPDCCH decoding and PDSCH decoding succeeds, timing for performing UL transmission by self-carrier scheduling or cross-carrier scheduling in advance If the UL transmission is in the SF # (n + 4), the transmission of the UL grant is SF # n, and in the case of the TDD, the UL transmission according to the transmission of the UL grant is performed separately in Table C- If the relationship is (For example, 16us, 20us, or 25us, or a different value (for example, 16us, 20us, or 25us) after UL transmission of a UE ) So that it can be performed immediately. Or to perform only LBT during a single interval interval. Since the LBT is performed once in the DL when transmitting the UL grant, the terminal does not perform the UL LBT for UL transmission intended by the UL grant or performs a simple LBT operation without back-off to transmit the UL . Here, the UL transmission may be performed after a certain period regardless of the subframe boundary, or may be transmitted according to the OFDM symbol (or SC-FDMA symbol) boundary, or may be transmitted in accordance with the UL subframe boundary. There may be a way to transmit. However, it is desirable to set the DL-UL switching time considering the DL-UL switching time when setting an arbitrary interval.

Table C-1 k for TDD configurations 0-6

As another example of the method of performing LBT for UL transmission in the LAA cell, the success or failure of decoding of the DL PDSCH for an arbitrary UE in the last SF of the on-going DL transmission burst (e.g., UE1) (E.g., 16us, 20us, or 25us, or some other value) after UL transmission at which a UL transmission may occur at a subframe boundary or not. That is, since the processing time for decoding the PDSCH can not be guaranteed before the UL transmission after an arbitrary interval (for example, 16us, 20us, or 25us, or another value) after transmission of the on-going DL transmission burst, the decoding time of the PDSCH due to the decoding time of the PDSCH in a subframe boundary where decoding can not be determined or an arbitrary interval (for example, 16us, 20us, or 25us, or another value) If PDSCH decoding is performed despite the high level of interference due to high power level of the desired signal, the configuration of the ending subframe is indicated by subframe configuration through common control signaling for every SF. (n + 2) of the on-going DL transmission burst (eg UE1), since the UE # indicates the number of OFDM symbols occupied by the ending subframe (n + 3) is an ending subframe of an on-going DL transmission burst, that is, SF # (n + 2) is not a ding subframe and SF # (PDSCH) is transmitted and the PDSCH is decoded and succeeded, an arbitrary UE in the SF # (n + 3) is allocated to the UE (eg UE1) regardless of whether the PDSCH for the UE1 is scheduled For UL transmission, a UL grant transmitted by self-carrier scheduling or cross-carrier scheduling in advance (eg, (E.g., 16us, 20us, or 25us, or some other value) after the DL transmission of the on-going DL transmission bus without the UL LBT. Or to perform only LBT during a single interval interval. Since the LBT is performed once in the DL when transmitting the UL grant, the terminal does not perform the UL LBT for UL transmission intended by the UL grant or performs a simple LBT operation without back-off to transmit the UL . (For example, 16us, 20us, or 25us, or another value) after an arbitrary interval (for example, 16us, 20us, or 25us) Transmission may be considered, or it may be transmitted according to the OFDM symbol boundary, or there may be a method of transmitting according to the subframe boundary.

The following describes a method for performing UL LBT for UL transmission in an LAA cell as yet another embodiment.

22, there may be a case in which consecutive DLs of a DL that has received an UL grant and a UL transmission corresponding to the corresponding UL grant are discontinuously transmitted in order to continuously perform UL transmission after DL transmission . In FIG. 22, the UL transmission of the UL grant and the SF # n + 4 corresponding to the UL grant and the subsequent SF # n + 3 are discontinuous. In FIG. 22, the last subframe of the LAA burst may be a full subframe (eg, 1 ms, 14 OFDM symbols) or an ending partial subframe (eg, the number of occupied OFDM symbols is {3, 6, 9, 10, Partial OFA symbols constituting the initial subframe (eg, 1 ms, 14 OFDM symbols) or OFA symbols smaller than 14 (eg 7 OFDM symbols) in the initial partial subframe, subframe. In constructing an initial or ending partial subframe, it is not possible to construct a DL burst by a partial subframe alone.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, when the base station transmits UL grant in subframe n and UL transmission in subframe n + 4, as shown in FIG. 22, It is impossible to know whether or not the channel can be accessed by succeeding the LBT for DL transmission in SF # n + 3. Therefore, if the UE knows that the SF # n transmitting the UL grant is the last SF or if it can be known through the common control signaling, the UE uses the OFDM symbol before the UL subframe boundary for the UL transmission in the SF # n + And sets the UL LBT to the UL LBT during the forward OFDM symbol (eg 1 or 2 OFDM symbol) of SF # n + 4.

As another embodiment of the method for performing LBT for UL transmission in the LAA cell, when UL transmission is set to always perform transmission in the UL subframe boundary, the UL LBT before the UL subframe boundary The partial subframe in SF # n + 3 must be set as a partial subframe even though SF # n + 3 can be DL. The partial subframe in SF # n + 3 can not be constituted by the partial subframe alone. The subframe configuration in SF # n + 2 must be set to be a full subframe. To do so, the DL subframe in SF # n + 1 must first be configured as an initial partial subframe by performing CCA, or SF # n + Only LBT should be performed. In this case, the flexibility of scheduling can be reduced due to the DL scheduling restriction. Therefore, even if in a set, such as 22 SF # n + 3 is Full subframe configuration, DL-UL switching gap also can not be guaranteed 1) SF # n + 4, or to drop the UL transmission in, 2) No UL In order to perform LBT with LBT or LBT with a single sensing interval, or with LBT with a back-off that has a contention window size of small value, one or two of the UL subframes in SF # n + A time interval for performing LBT with a DL-UL switching gap and a single sensing interval using a SC-FDMA symbol or a back-off having a contention window size with a small value Can be set. If the UE can recognize that the configuration in the last SF # n + 3 is a DL full subframe, the eNB determines whether the UE should perform the LBT at a certain time when transmitting the UL grant in SF # n. However, if the UE does not know the configuration information of the last DL subframe in the SF # n + 3 as a case, there is no way to know at what point the UE should perform the LBT. When UL LBT synchronization is required to maintain multiuser multiplexing between UEs, some UEs perform UL transmission at UL subframe boundary by performing LBT ahead of UL subframe boundary, and the first one or two SC-FDMA symbols The UEs attempting to perform the UL LBT and performing the UL transmission are required to transmit UL Since the UL transmission at the L subframe boundary is likely to cause the channel to be busy in the first one or two SC-FDMA symbols of the UL subframe, the UL transmission can not be performed even though the UL grant is received in the SF # n Lt; / RTI &gt; Therefore, when transmitting an UL grant, signaling for the UL LBT at the terminal (ie, before the UL subframe boundary or in the first one or two SC-FDMA symbols in the UL subframe) is included in the UL grant. , Or signaling to the point at which UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to difference in UL LBT execution time between terminals and allowing multi-user multiplexing .

Also, considering UL LBT that performs 25us-based CCA with UL LBT method, the following four points can be considered as the transmission time to perform UL transmission within one UL subframe.

- 1. Start of DFTS-OFDM symbol 0 (ie start transmission at DFTS-OFDM symbol 0)

- 2. Start of DFTS-OFDM symbol 1 (ie start transmission on DFTS-OFDM symbol 1)

- 3. 25 us after start of DFTS-OFDM symbol 0 (i.e. DFTS-OFDM symbol 0 After the point 25us  Start transmission from)

- 4. 25 us + TA value after start of DFTS-OFDM symbol 0 (i.e. DFTS-OFDM symbol After 0  ( 25us  + TA (Timing advance) value)

In the case of 3 and 4, which can be set to enable transmission start within the DFTS-OFDM symbol 0, the next symbol DFTS-OFDM symbol 1 is allocated to occupy a part of the DFTS-OFDM symbol 0 after the LBT success. To expand the cyclic prefix of

In this case, as a method for synchronizing the UL LBT in order to maintain the multiuser multiplexing between the terminals, a method for maintaining the multiuser multiplexing between terminals in the case of considering the above four methods of transmission time after UL LBT, UL grant must be transmitted by including in the UL grant a signaling indication indicating one of the above four points for the transmission time after the UL LBT in the terminal when transmitting the UL grant or performing UL LBT through common control signaling Time signaling, thereby avoiding LBT failure due to the difference in UL LBT performance between the UEs, and to enable mulit-user multiplexing. However, if there are multiple UEs that are scheduled in the same subframe regardless of a single subframe or multiple subframes, when receiving signaling related to different transmission time points, the cyclic extension transmitted after the preceding LBT in the UE performing the transmission first The LBT in the terminal receiving the signaling to perform the LBT may be failed, so that the multiplexing of the multi-user may not be possible. Therefore, when scheduling different terminals in the same subframe as a method for solving the occurrence of the case, signaling for the UL transmission start time transmitted through the UL grant can be similarly set and transmitted , When the UE is set to perform transmission in different subframes in the same subframe, the UE is set to expect to perform the same signaling from the UL grant as a transmission time at which UL transmission can be performed in one UL subframe . Alternatively, when scheduling the UE to perform scheduling to different UEs in the same subframe, the Node B performs signaling to the UE when UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to a difference in UL LBT performance between UEs , a method for enabling multi-user multiplexing can be considered.

For example, if UE1 and UE2 are scheduled to be scheduled in the same subframe, UE1 receives signaling through UL grant to start transmission in DFTS-OFDM symbol 1 and UE2 receives signaling from 25us after DFTS-OFDM symbol 0 If the signaling is received through the UL grant to start, the UE2 starts the transmission after starting the DFTS-OFDM symbol 0 by extending the cyclic prefix at DFTS-OFDM symbol 1 from 25us. The UL LBT of 25 us is performed immediately before the DFTS-OFDM symbol 1, so that the channel is busy due to the cyclic prefix transmission at the UE 2, so that the UE 1 fails the UL LBT and transmits the scheduled transmission It can be impossible. Therefore, when the base station causes the UEs to perform scheduling to different UEs in the same subframe, signaling for the UL transmission start time transmitted through the UL grant can be similarly set and transmitted. In the UE's view, It is possible to set up the same signaling to be performed from the UL grant as a transmission time at which UL transmission can be performed in one UL subframe. Alternatively, when scheduling the UE to perform scheduling to different UEs in the same subframe, the Node B performs signaling to the UE when UL LBT should be performed through common control signaling, thereby avoiding LBT failure due to a difference in UL LBT performance between UEs , a method for enabling multi-user multiplexing can be considered.

In the case of a terminal that has been scheduled to transmit to multiple subframes, signaling for the four transmission times shown above can be set to apply only to the initial transmission UL subframe. For a subframe that is not the starting point, it can be set to perform only transmission in DFTS-OFDM symbol 0 or DFTS-OFDM symbol 1 as its starting point to reduce the signaling overhead in the UL grant. That is, a 1-bit indication is added to the UL grant for scheduling multiple subframes, and the PUSCH start time in subframes other than the starting subframe is set to be the same indication. This is a method that enables UL LBT of UEs scheduled to be transmitted in a trailing subframe due to transmission of UEs that are scheduled in multiple subframes in a preceding subframe with a minimum control overhead.

The LBT method for performing transmission of a DL control channel (e.g., PDCCH, EPDCCH) considering transmission of UL grant only and transmission of UL data corresponding to the corresponding UL grant will be described.

As shown in FIG. 23, when the UL data traffic transmitted on the LAA SCell is self-carrier-scheduled through the control channel transmitted on the corresponding LAA SCell, the control channel transmitting only the UL grant is transmitted through the PDCCH of the DL sub- In the case of transmission, that is, when the UL grant only transmission is transmitted through the PDCCH without PDSCH transmission in one subframe, the OFDM symbols in the subframe that the PDSCH region can have may be blanked And the corresponding blanked OFDM symbol (s) of the unlicensed carrier may be allowed to access the medium from the blanked OFDM symbol (s) by channel access from other nodes or Wi-Fi nodes. Therefore, even though the BS attempts to secure the eNB transmission through the setting of the maximum channel occupancy time (MCOT) that can be set differently according to the channel access priority class, the LBT performed for the UL grant only transmission without the PDSCH is successful The PDSCH (s) and the scheduled PUSCH (s) are transmitted for transmission of the PDSCH and the scheduled PUSCH in the next subframes by transmission and interference by other nodes due to absence of PDSCH transmission in the corresponding subframe, Lt; / RTI &gt; 23 illustrates a case where a corresponding UL grant only transmission occurs in a start subframe of an LAA burst on an unlicensed carrier. However, the present invention is not limited to this case, but a subframe The same problem may occur when blanked OFDM symbols are generated in a subframe where UL grant only transmission is performed.

Method A) As shown in FIG. 24, in the case of UL grant-only transmission, the UL grant is transmitted through the EPDCCH, so that the EPDCCH is allocated in the PDSCH region with the PDSCH in the FDM scheme. PDSCH region, thereby preventing the medium from being accessed by the LBT in the blanked OFDM symbol (s) by the other nodes, and also preventing UL traffic corresponding to the corresponding UL grant In the LBT performance method used in the UE (s) at the time of transmission of the UL grant, depending on the LBT scheme performed at the time of transmission of the UL grant or the length of the MCOT secured at the time of transmission of the UL grant, it is possible to perform fast channel access for UL data transmission by performing LBT in a single interval LBT interval (for example, 16 us, 25 us, 34 us or 43 us). Or in the LBT performing method used in the UE (s) at the time of transmitting the UL traffic corresponding to the UL grant, depending on the LBT scheme performed at the time of transmitting the UL grant or the length of the MCOT secured at the time of transmitting the UL grant, When transmitting UL traffic from outside, it can be configured to perform cat-4 LBT. Alternatively, a method for signaling whether the terminal should perform a cat-4 LBT method to perform a single interval LBT to enable fast channel access as an LBT for UL traffic or to perform a backoff in the case Can be considered.

Method B) When UL grant only transmission without PDSCH transmission in one subframe is transmitted through PDCCH or EPDCCH, as shown in FIG. 25, when the LBT in the subframe in which the UL grant only is transmitted and the PDSCH in the next subframe are transmitted In the subframe, a method may be considered in which the LBT is set to be independent of the LBT in the subframe for UL grant only transmission so as to match the channel access priority class for the PDSCH. In this case, when the LBT is successful according to the success of the LBT in the subframe where the PDSCH is transmitted, the MCOT is set from the corresponding subframe. However, the UL subframe in which the UL traffic corresponding to the pre- The UE can perform LBT in a single interval LBT interval (for example, 16us, 25us, 34us, or 43us) to enable fast channel access for UL data transmission if the UE exists in the MCOT. Or the LBT scheme performed in the UL grant transmission in the LBT performance method used in the UE (s) at the time of transmitting the UL traffic corresponding to the UL grant or the length of the MCOT secured by the LBT in the subframe transmitting the PDSCH 4 LBT when UL traffic is transmitted outside the MCOT. Alternatively, a method for signaling whether the terminal should perform a cat-4 LBT method to perform a single interval LBT to enable fast channel access as an LBT for UL traffic or to perform a backoff in the case Can be considered.

Method C As shown in FIG. 26, in order to prevent a case where a blank OFDM symbol (s) occurs in a PDSCH region, which may occur when UL grant only transmission is transmitted through a PDCCH, In order to prevent access to medium by LBT in blanked OFDM symbol (s) by nodes, the PDSCH to be transmitted in the next subframe can be transmitted without additional LBT in MCOT. As an example of the reservation signal, there may be one EPDCCH transmission common to all UEs. In another embodiment, the transmission at the 0, 4, 5, and 7 OFDM symbol indexes of the CRS ports 0 to 1, symbol, and CRS ports 0 to 4 may be extended and transmitted, and a method of transmitting dummy data to a RB in a specific frequency region as a reservation signal may be considered. Also, in the LBT performance method used in the UE (s) at the time of transmitting the UL traffic corresponding to the corresponding UL grant, depending on the length of the MCOT secured at the transmission of the UL grant or the LBT scheme performed at the time of transmission of the UL grant, UL traffic may be performed in a single interval LBT interval (for example, 16us, 25us, 34us, or 43us) to enable fast channel access for UL data transmission. Or in the LBT performing method used in the UE (s) at the time of transmitting the UL traffic corresponding to the UL grant, depending on the LBT scheme performed at the time of transmitting the UL grant or the length of the MCOT secured at the time of transmitting the UL grant, When transmitting UL traffic from outside, it can be configured to perform cat-4 LBT. Alternatively, a method for signaling whether the terminal should perform a cat-4 LBT method to perform a single interval LBT to enable fast channel access as an LBT for UL traffic or to perform a backoff in the case Can be considered.

24 to 26 illustrate a case where a corresponding UL grant only transmission occurs in a start subframe of an LAA burst in an unlicensed carrier as an example, and a solution thereof is shown in Figs. 24 to 26 and methods A to C The present invention is not limited to this, but a problem that occurs when a blanked OFDM symbol is generated in a subframe in which UL grant only transmission is performed in a subframe other than the beginning of an LAA burst in an unlicensed carrier is also described with reference to FIGS. 26 and Methods A-C. 23 to 26 in the present invention are described with reference to a full subframe (e.g., a subframe composed of OFDM symbols). However, when the starting subframe is a partial subframe (e.g., a subframe composed of OFDM symbols smaller than 14) the present invention can be applied to a case in which the partial subframe is composed of partial subframes.

In the case of transmitting only an UL grant, an LBT method of a DL control channel (e.g., PDCCH, EPDCCH) including an UL grant considering a channel access priority class of UL traffic corresponding to an UL grant, The LBT method for transmission will be described.

The LBT method for UL traffic transmission corresponding to the UL grant when the UL grant is transmitted together with the PDSCH transmission will be described.

First, when the UL grant is transmitted together with the PDSCH transmission, the PDCCH as the control channel and the LBT of the EPDCCH to which the UL grant is transmitted are transmitted through the channel using the LBT parameters according to the channel access priority class of the PDSCH access.

Assuming that the minimum time latency between the UL grant and the UL transmission is 4 ms, since the MCOT is 2 ms or 3 ms when the CAPC of the PDSCH is 1 or 2, the UL grant corresponding to the UL grant is transmitted as the UL grant (Hereinafter referred to as &quot; MCOT &quot;) of the DL transmission burst. Therefore, the LBT of the UL Transmission corresponding to the UL grant can be set to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE receiving the UL grant and transmitting the UL. If the UE has multiple CAPCs to transmit, the UE can be configured to perform Cat-4 LBT based on the CAPC having the lowest priority among the CAPCs.

As another embodiment, when the CAPC of the PDSCH transmitted with the UL grant is 3 or 4, since the MCOT is 8 ms or 10 ms, the UL transmission corresponding to the UL grant can be transmitted in the MCOT or can be transmitted outside the MCOT . First, if transmission of DL transmission and UL LBT and UL transmission can occur in MCOT, single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, UL transmission, UL LBT and UL transmission can not occur in the MCOT. For UL transmission that can occur within the MCOT limit, single interval UL transmission scheduled to be carried out by the UL grant so that UL transmission is performed through LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, N can be a natural number of 1 or more) For transmission, the terminal may be configured to perform LBT according to the CAPC of UL traffic to be transmitted. If the UE has multiple CAPCs to transmit, the UE can be configured to perform Cat-4 LBT based on the CAPC having the lowest priority among the CAPCs.

In another embodiment, when the CAPC of the PDSCH transmitted with the UL grant is set to 3 and the UL grant is also performed according to the CAPC 3, the CAPC of the UL traffic to be actually transmitted by the UE corresponding to the UL grant is 3 or less UL transmission is performed through a single interval LBT (eg, 16us, 25us, 34us, 43us or 16 + 9 * N, where N may be a natural number of 1 or more) regardless of the CAPC of UL traffic , And if the CAPC of the UL traffic is 4, it can perform the UL transmission by performing the cat-4 LBT with the LBT parameter according to CAPC 4 of the UL traffic regardless of whether the UL transmission is within the MCOT or outside the MCOT have. As another embodiment, when the CACP of the PDSCH transmitted with the UL grant is set to 4 and the UL grant is also performed according to the CAPC 4, the terminal corresponding to the UL grant transmits a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1).

As another embodiment, when the LBT is performed through the CAPC value X of the PDSCH transmitted with the UL grant, a single interval LBT (eg, 16us, 25us, 34us, 43us or 16 + 9 * N, N may be a natural number greater than or equal to 1), and if not, UL transmission scheduled according to the UL grant is performed according to the CAPC of UL traffic to be transmitted by the UE LBT &lt; / RTI &gt; If the UE has multiple CAPCs to transmit, the UE can be configured to perform Cat-4 LBT based on the CAPC having the lowest priority among the CAPCs.

As another embodiment of the present invention, a base station may perform LBT-related signaling, i.e., a CAPC (eg, channel access priority class {1, 2, 3, or 4}) or a CW Or CWp) to the terminal. At this time, the UE compares the CAPC and the CW of the UL traffic to be transmitted by the UE based on the CAPC as the DL LBT or the CW performed by the base station for UL grant transmission in the transmission of the UL transmisson corresponding to the corresponding UL grant, If the CAPC or CW as the LBT is equal to or greater than the CAPC or CW of the UL traffic, the UL transmission (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1) And if it is not, it may be configured to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant. This method can be applied regardless of whether the UL grant (s) and the UL grant corresponding to the UL grant (s) are within the MCOT and whether the UL grant is transmitted concurrently with the PDSCH or only the UL grant It is applicable.

In the present invention, when the UL LBT is performed, the LBT type that can be performed by the UE as the LBT type may be a cat-4 LBT or a single interval (eg 16us, 25us, 34us, 43us or 16 + 9 * N, N May be a natural number greater than or equal to 1). At this time, the LBT type can be indicated through the UL grant as shown in the description of the present invention.

In case of performing Cat-4 LBT, based on the recent received buffer status report and UL traffic received from the UE, the BS transmits the LBT priority class (or the LBT priority class channel access priority class), and the MS can signal all the traffic of the priority class that is equal to or higher in priority than the LBT priority class (or the number of the LBT priority class is smaller) based on the signaled LBT priority class s), and the base station is able to schedule more than the LBT priority class signaling to the UE or all the traffic (s) of the higher priority class To the mobile station.

In case of performing LBT with a Cat-2 LBT, that is, a single interval (eg, 25us), it is necessary to perform the LBT based on the recent received buffer status report and the UL traffic received from the terminal, The LBT priority class used for link transmission can be signaled to the UE by the DL LBT priority class in the signaling field of the UL LBT priority class (or channel access priority class) when transmitting the common-PDCCH or UL grant to the UE , The UE shall send a subframe with the minimum required to transmit all traffic (s) of the priority class equal to or higher in priority than the LBT priority class (or a smaller number of the LBT priority class) based on the signaled LBT priority class. And the BS determines whether the LBT priority class is equal to or higher than the LBT priority class based on the LBT priority class signaled by the BS to the MS Do not have a lot of subframe scheduling more than the minimal required to send all traffic (s) of high LBT priority class to the terminal.

In the case of the UE performing the LBT of the Cat-4, in the case of the terminal, the UE transmits the LBT priority class to the UL traffic and the BSR based on the common PDCCH received by the base station or the signaled LBT priority class included in the UL grant LBT priority class so that the transmission to the UL can be performed according to the priority of the UL traffic according to the LBT priority class. In contrast, when the terminal performs the 25us LBT, the terminal assigns a priority class corresponding to the signaled LBT priority class included in the common PDCCH received by the base station or the UL grant to the LBT priority class, and transmission to the UL can be performed according to the priority of UL traffic according to the LBT priority class.

The present invention provides a UL traffic transmission corresponding to an UL grant when an UL grant is transmitted together with a PDSCH transmission in consideration of a contention window (CW) and a channel access priority class (CAPC) And an LBT method of a channel through which an UL grant is transmitted will be described. The present invention also describes an LBT method of a DL control channel (e.g., PDCCH, EPDCCH) including UL traffic and UL grant corresponding to UL grant when only UL grant is transmitted.

First, an LBT method for UL grant transmission and an LBT setting method for UL traffic corresponding to an UL grant in a case where an UL grant is transmitted together with transmission of a PDSCH will be described.

1-1) When the base station manages the CW specific to the UE for each UE or each UE (s) allows the base station to know the CW of the UE,

It may be difficult for the BS to know the CAPC of the UL traffic to be transmitted by each UE before transmission of the UL grant. Therefore, the BS determines the CW according to the CAPC for the PDSCH (s) to be transmitted and performs the DL LBT for the control channel and the PDSCH transmission, and the DL grant included in the control channel is also performed in the same DL LBT. At this time, in a method for performing UL LBT for transmission of UL traffic (s) corresponding to an UL grant (s), a CW (eg CW_eNB) of DL LBT parameters used by a base station for transmission of UL grant, The UL LBT for transmission of the scheduled UL traffic (s) corresponding to the UL grant (s) is compared with the single interval LBT (s) by comparing them based on the CW (eg CW_UE For example, if UL transmission is set to perform UL transmission through a UL grant (e.g., 16us, 25us, 34us, 43us, or 16 + 9 * N, N may be a natural number greater than or equal to 1) May be configured to perform LBT according to the CAPC of UL traffic to be transmitted. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. Also, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit the signaling to the UE (s) through the common control channel or the like.

More specifically, the CW (eg, CW_eNB) as a DL channel access parameter used by the base station for transmission of the UL grant (s) is used as the traffic (s) of the UE (s) scheduled by the UL grant (s) ) Or a maximum value of the CWs (eg CW_UE (s)) for the UL grant (eg, Equation 4-1 or Equation 4-2), the base station transmits a CW having a sufficient length (Eg 16us, 25us, 34us, 43us or 16 + 9 * N) to perform fast channel access as UL LBT for UL transmission for UL traffic corresponding to UL grant (s) N may be a natural number greater than or equal to 1). As an example, the corresponding case can be expressed by the following Equation 4-1 or Equation 4-2. Equation 4-1 is a condition that is equal to or greater than the maximum value of the CWs (eg CW_UE_i, p_j) of all CAPCs for the traffic (s) of the UE (s) scheduled by the UL grant (s) Equation 4-2 represents the maximum value of the CWs (eg CW_UE_i, p_j) of the same CAPC for the traffic (s) of the UE (s) scheduled by the UL grant (s) It is a representation of the condition of greater or equal.

Equation (4-1)

Here, p_j denotes an index of the channel access priority class, and i denotes an index of the UE (s) scheduled by the UL grant (s).

Equation (4-2)

Here, p_j denotes an index of the channel access priority class, and i denotes an index of the UE (s) scheduled by the UL grant (s).

CW for the UL traffic (s) of the UE (s) scheduled by the UL grant (s) managed by the base station, CW as the channel access parameter used for the transmission of the UL grant (s) The UE can be configured to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. Also, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit the signaling to the UE (s) through the common control channel or the like.

As another embodiment, as a method for enabling fast channel access to the UL traffic (s) of the UE (s), a UE to be scheduled for CW (or CAPC) in the eNB for performing LBT on the control channel and PDSCH transmission (or CAPCs) with respect to the UL traffic (s) of the base station (s) to perform the DL LBT on the control channel including the UL grant and the PDSCH transmission. This is set so that the CW value of the LBT used for transmission of the UL grant (s) is not less than the CW (or CAPC) maximum of the UL traffic (s), so that the UL transmission for the UL traffic corresponding to the UL grant it is possible to perform UL transmission through fast channel access, ie, single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1). Also, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit the signaling to the UE (s) through the common control channel or the like.

1-2) If the base station manages only the CW for the base station transmission without the CW information of the terminal and each UE (s) manages the CW,

In one embodiment, the BS informs the UE of UL grant or common control signaling of the CW or CAPC of the LBT performed by the BS to transmit the UL grant (s), thereby enabling the UE to detect UL grant or common control signaling UL LBT for transmission of scheduled UL traffic (s) corresponding to UL grant (s) through comparison of CW with UL traffic or CAPC comparison for UL transmission corresponding to UL grant according to information is called single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N is a natural number greater than or equal to 1) The UE can perform the LBT according to the CAPC of the UL traffic to be transmitted. When the CW comparison is performed and the UL LBT scheme is set, if the CW at the time of transmission of the UL grant is equal to or greater than the CW of the UL traffic managed by the scheduled UE corresponding to the UL grant, the single interval LBT is performed And if not, perform the cat-4 UL LBT based on the CW of the UL traffic managed by the UE. In the case of setting the UL LBT scheme by performing the CAPC comparison, the single-interval LBT is performed when the CAPC at the transmission of the UL grant is equal to or greater than the CAPC of the scheduled UL traffic corresponding to the UL grant, 4 UL LBT based on the CAPC of the UL traffic managed by the UE.

In another embodiment, when an LBT performed by the base station for UL grant (s) transmission is performed according to the CAPC of the PDSCH (s), if there is UL transmission by UL grant (s) in the MCOT, UL transmission is performed through a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1) The UL can perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant.

The following describes an LBT method for UL grant transmission and an LBT setting method of UL traffic corresponding to the UL grant when only UL grant is transmitted without PDSCH transmission.

2-1) When the base station manages the UE-specific CW for each UE or each UE (s) makes the base station know the CW of the terminal,

In the case where only UL grant is transmitted without PDSCH transmission, it is impossible to know which values to use as DL channel access parameters for UL grant. Therefore, the base station arbitrarily selects the DL channel access parameter, (eg CW_EnB) for the traffic (s) of the UE (s) scheduled by the UL grant (s) managed by the base station is greater than the maximum value of the CWs (eg CW_UE (s) In the same case (eg, Equation 4-1 or Equation 4-2), since the base station has performed the DL LBT with a CW of sufficient length from the transmission of the UL grant, the UL grant (s) corresponding to the UL grant UL transmission can be configured to perform UL transmission through a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1) to perform fast channel access as a UL LBT. have. As an example, the corresponding case can be expressed by the following Equation 4-1 or Equation 4-2. Equation 4-1 is a condition that is equal to or greater than the maximum value of the CWs (eg CW_UE_i, p_j) of all CAPCs for the traffic (s) of the UE (s) scheduled by the UL grant (s) Equation 4-2 represents the maximum value of the CWs (eg CW_UE_i, p_j) of the same CAPC for the traffic (s) of the UE (s) scheduled by the UL grant (s) It is a representation of the condition of greater or equal. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. Further, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit it as a base station signaling to the UE (s) through a common control channel or the like

CW for the UL traffic (s) of the UE (s) scheduled by the UL grant (s) managed by the base station, CW as the channel access parameter used for the transmission of the UL grant (s) The UE can be configured to perform the LBT according to the CAPC of the UL traffic to be transmitted by the UE for the UL transmission scheduled by the UL grant. In addition, when the condition of the single interval UL LBT is not matched, since each terminal can not perform a single interval LBT, the BS transmits to the UE the largest CW size of the UE (s) to be scheduled by the UL grant (s) (S) to be performed by the UL grant (s) and to perform the UL LBT for the UL traffic by informing the UE of the largest CW size for the CAPC of the UL traffic of the UE And may set a common backoff counter based on the largest CW size of the UE (s) to be scheduled by the UL grant (s), and signaling the UE. Also, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit the signaling to the UE (s) through the common control channel or the like.

As another embodiment of the present invention, as a method for enabling fast channel access to UL traffic (s) of UE (s), scheduling of CW (or CAPC) in the eNB for performing DL LBT of a control channel including only UL grants (Or CAPCs) with respect to the UL traffic (s) of the UE (s) to be performed, and perform the DL LBT for the control channel including the UL grant. This is set so that the CW (or CAPC) value of the LBT used for transmission of the UL grant (s) is not less than the CW (or CAPC) maximum of the UL traffic (s) For UL transmission, UL transmission can be performed through fast channel access, ie single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1). Also, the base station may transmit signaling for the UL LBT of the UE (s) in the UL grant and transmit the signaling to the UE (s) through the common control channel or the like.

2-2) If the base station manages only the CW for the base station transmission without the CW information of the terminal and each UE (s) manages the CW,

In one embodiment, the BS informs the UE of UL grant or common control signaling of the CW or CAPC of the LBT performed by the BS to transmit the UL grant (s), thereby enabling the UE to detect UL grant or common control signaling UL LBT for transmission of scheduled UL traffic (s) corresponding to UL grant (s) through comparison of CW with UL traffic or CAPC comparison for UL transmission corresponding to UL grant according to information is called single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N is a natural number greater than or equal to 1) The UE can perform the LBT according to the CAPC of the UL traffic to be transmitted. When the CW comparison is performed and the UL LBT scheme is set, if the CW at the time of transmission of the UL grant is equal to or greater than the CW of the UL traffic managed by the scheduled UE corresponding to the UL grant, the single interval LBT is performed And if not, perform the cat-4 UL LBT based on the CW of the UL traffic managed by the UE. In the case of setting the UL LBT scheme by performing the CAPC comparison, the single-interval LBT is performed when the CAPC at the transmission of the UL grant is equal to or greater than the CAPC of the scheduled UL traffic corresponding to the UL grant, 4 UL LBT based on the CAPC of the UL traffic managed by the UE.

In another embodiment, when the base station performs an LBT performed for UL grant (s) transmission according to a CAPC arbitrarily set by the base station, if the UL transmission by the UL grant (s) is present in the MCOT, the scheduled UL traffic s UL transmission through a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1) When the UL transmission is scheduled, the UE can perform the LBT according to the CAPC of the UL traffic to be transmitted to the UL transmission scheduled by the UL grant.

The present invention relates to a CWS adaptation method for UL LBT in a terminal.

In the case where the base station manages the CW specific to the UE or each UE (s) knows the CW of the UE, the base station may update and adapt the CW of the UE (s) CW update and adaptation of each terminal can be performed based on the UL transmission. In the case of the terminal, the PUSCH transmission in the unlicensed carriers may be dropped in the power limited situation of the terminal according to the priority between the channels of the licensed carriers and the channels of the unlicensed carriers in the operation based on the carrier aggregation. However, the BS can not know the power limited situation of the UE and can not know whether the UE has transmitted the channels dropped due to the power limitation, but expects the UE to transmit the scheduled channel and expect the reception at the corresponding reception timing . However, in this case, when the UL transmission transmitted by the UE drops, the BS determines it as a NACK and uses the contention window (CW) according to the NACK as information for updating the CW. In this case, dropped UL transmission may not be useful information for determining whether the channel is busy or idle between the UE and the BS. Therefore, when the base station performs CW update and adaptation for each UE, the base station updates the base station based on reception of the PUSCH transmitted from the base station, and if base station decoding based on the PUSCH transmission is determined to be ACK The CW of the corresponding UE is reset, and the UE determines that the channel for the medium between the UE and the BS is idle, and the CWp (p = {1,2,3, 4} may be reset to CWmin, and when it is determined that the base station decoding based on the PUSCH transmission is failed and NACK is determined, the CW of the corresponding UE is doubled. At this time, It is judged that the channel is busy, so that CWp (p = {1,2,3,4}), which may be differently set according to the channel access priority class, is doubled for all CWp . In addition, as a method of recognizing the PUSCH transmission from the UE, the base station may perform energy detection on the PUSCH transmission through detection of the UL DM-RS, or when the PUSCH is scheduled with the SRS, energy detection may be performed to determine whether the PUSCH is transmitted.

The present invention relates to a CWS adaptation method in UL LBT for UL PUSCH transmission in a terminal.

In the case where the base station manages the CW specific to the UE or each UE (s) knows the CW of the UE, the base station may update and adapt the CW of the UE (s) CW update and adaptation of each terminal can be performed based on the UL transmission. In the case of the terminal, the PUSCH transmission in the unlicensed carriers may be dropped in the power limited situation of the terminal according to the priority between the channels of the licensed carriers and the channels of the unlicensed carriers in the operation based on the carrier aggregation. However, the BS can not know the power limit situation of the UE and can not know whether the channels that the UE has dropped due to power limitation. In addition, the base station can not distinguish the following three cases in which the PUSCH can not be transmitted from the terminal. Therefore, the present invention proposes a method for distinguishing the following three cases and describes a method of adapting the CWS according to the method.

- First, if the PUSCH can not be transmitted due to not receiving the UL grant,

- Second, if LBT fails prior to PUSCH transmission and PUSCH can not be transmitted

- Third, if LBT succeeds before PUSCH transmission but fails to transmit PUSCH (for example, UL power limitation case)

First, as a method for distinguishing the first case and the second case, when an LAA SCell is set to receive cross-carrier scheduling from a cell of a licensed carrier, a UL grant for transmission of UL PUSCH on the LAA scell E) When PDCCH and PDSCH are transmitted in the downlink at the same time, it sends feedback to the PDSCH, not the no transmission case, but an explicit HARQ-ACK feedback ("ACK, NACK" or "ACK, NACK, NACK / DTX" (E) PDCCH scheduled to be PDSCH is successfully received at the UE, and it can be considered that the UL (PDCCH) is UL Since the base station knows that the grant has been transmitted, the BS can determine that the UL grant has also been successfully received. In this case, the UE can not transmit the PUSCH because it has not received the UL grant One case can be excluded, and the case can be excluded in the event for increasing the CWS to adjust the CWS used to perform the UL LBT for the PUSCH as the LBT parameter for the transmission of the next PUSCH. This is because the transmission of the (E) PDCCH including the UL grant is transmitted from the cell of the licensed carrier, which can not help informing the state of the channel collision for transmission of the UL PUSCH on the LAA SCELL. To be excluded when adjusting CWS for link transmission. That is, when the base station can not receive (or detect) the PUSCH at the transmission timing of the PUSCH determined by the reception of the UL grant, the UL grant is successfully received but the PUSCH due to the failure of the PUSCH LBT fails to be transmitted The base station determines that the CWS for the terminal is doubled or increased from the previous CWS in that case.

This is applicable even when the unlicensed carrier LAA SCell is set to self-carrier scheduling. (E) PDCCH including UL grant for transmission of UL PUSCH on the LAA Scheduler and PDSCH on the LAA SCELL at the same time as the feedback to the PDSCH, an explicit HARQ-ACK feedback (&quot; ACK, NACK, or at least one of ACK, NACK, NACK / DTX, or at least ACK or NACK is detected), the BS schedules the PDSCH when the BS detects on a licensed carrier or unlicensed carrier E) PDCCH is successfully received at the UE, and since the base station knows that it has transmitted an UL grant to the corresponding (E) PDCCH, the BS can determine that the UL grant has been successfully received. To perform the UL LBT for the PUSCH as the LBT parameter for transmission of the next PUSCH excluding the case where the PUSCH can not be transmitted due to the failure to receive the UL grant on the PUSCH When to adjust the CWS is for the event in order to increase the CWS it may be excluded. That is, when the base station can not receive (or detect) the PUSCH at the transmission timing of the PUSCH determined by the reception of the UL grant, the UL grant is successfully received. However, if the PUSCH fails to transmit due to the failure of the PUSCH LBT, It is determined that the CWS for the terminal is doubled or increased from the previous CWS.

Next, a second (when the PUSCH can not be transmitted due to failure of the LBT before the PUSCH transmission) and a third (when the LBT succeeds before the PUSCH transmission but the PUSCH can not be transmitted, for example, UL power limitation case) The implicit signaling and explicit signaling methods are described.

First, as an implicit signaling method, when the CA is configured for the power limited case of the UE, the priority is defined as a transmission priority defined in the 3GPP Rel-13 specification according to the channel type and the contents of the channel in different carriers (Eg, PRACH> PUCCH> PUSCH with UCI> PUSCH> periodic SRS), the PUSCH on the unlicensed carrier may have been dropped. Therefore, unlicensed PUSCH on the unlicensed carrier is considered to be dropped due to the power limited state of the UE when the transmission of the PRCH, the PUCCH, or the PUSCH with UCI is detected, which is higher in priority than the PUSCH on the carrier, When the CWS is adjusted, this case adjusts the CWS used to perform the UL LBT for the PUSCH as the LBT parameter for the next PUSCH transmission In the event that if I intended to increase the CWS it can be ruled out. That is, in this case, the LBT for the PUSCH has succeeded, but the PUSCH is not received in the transmission timing of the PUSCH due to the reception of the UL grant, considering that the PUSCH is not transmitted due to the power limit situation of the terminal, (Or detection) of the CWS is not doubled or the CWS of the corresponding UE is set to be not higher than that of the previous CWS.

In addition, this method may be configured to set the UL PUSCH differently depending on whether the UE receives cross-carrier scheduling or self-carrier scheduling. In the case of self-carrier scheduling, if it is determined that the UL grant has been successfully received, the PUSCH LBT is considered to be successful considering that the channel state is idle at the PUSCH transmission timing in the unlicensed carrier, but in the third case It is considered that the PUSCH can not be transmitted due to the power limited state of the UE and the PUSCH is not received (or detected) at the transmission timing of the PUSCH according to the reception of the UL grant, Or to not increase it from the previous CWS.

In the case of cross-carrier scheduling, the success of UL grant reception from the licensed carrier can not be considered as a method for determining the channel state at the PUSCH timing in the unlincensed carrier. In this case, the base station determines the second case and the third case It is determined whether the base station arbitrarily selects the second case (failure to transmit PUSCH due to failure of PUSCH LBT) or third case (case where PUSCH LBT succeeds but PUSCH can not be transmitted (eg power limitation case) In this case, if the PUSCH is not received, the CWS may be doubled or increased from the previous value. In this case, the CWS adaptation method of the base station may be applied. May be considered.

Next, when the CA is configured for the power limited case of the UE as the explicit signaling method, information on the PUCCH / PUSCH of the licensed PCell or the PUCCH / PUSCH of the licensed SCell and the PUSCH LBT failure on the LAA SCELL, A method of transmitting information including information on whether or not the SCELL PUSCH is dropping can be considered. Or a method of transmitting information on PUSCH LBT failure on another LAA SCELL, or information on whether LAA SCELL PUSCH is dropping according to a power limited situation, in the PUSCH of the LAA SCELL configured to be able to transmit after the LBT succeeds.

The present invention relates to a CWS adaptation method in UL LBT for UL PUSCH transmission in a terminal

The present invention relates to a signaling method of an LBT parameter for CWS adaptation in a UL LBT for UL PUSCH transmission in a terminal.

When the BS informs the UL LBT parameter to the UE, the BS does not know the channel access priority class of the traffic transmitted by the UE. Therefore, notifying the CWS of all the priority classes to the UE may result in a large signaling overhead, If you follow the channel access priority class that is used in the DL for the class, you can increase the related signaling overhead because the range of allowed CWp size is large as shown in the table below.

In addition, Table AAA-1 below can be used as an LBT parameter for the UL channel access priority class.

Table AAA-1

Note1: The 6ms MCOT can be increased to 8ms by adding one or more gaps, and the minimum duration of the interval that stops due to the gap must be 100us. And the maximum interval length must be 6 ms before including the any gap and the gap duration is not included in the channel occupancy time.

Note 2: If the absence of any other technology (eg Wi-Fi) on the same carrier is guaranteed, the MCOT may be up to 10 ms for LBT priority classes 3 and 4. Otherwise, LBT priority class 3, 4, the MCOT is as specified in note 1.

Therefore, in the present invention, a method of reducing signaling overhead in informing a CW size among LBT parameters that a BS can inform to a UE and a CWS adaptation method will be described.

First, the base station informs the UE of a common value for the CWS regardless of the priority class. Thus, the UE receiving the common value transmits a back-off message using the common value CWS according to the channel access priority class to be transmitted So that the LBT can be performed. That is, the BS determines whether to doubt or increase the CWS based on the reception of the PUSCH transmitted from the UE, and informs the UE of the common values regardless of the priority class when indicating the parameters for the LBT to the UE. Sets the CWS according to the common value in the LBT of the PUSCH to be transmitted, performs the LBT, and transmits the PUSCH according to the success of the LBT. When the common value is received through the UL grant, if the common value is 0, the LBT is set to the minimum value of the CW size of the channel access priority class for the PUSCH to be transmitted. If the common value is 1, the CW size The minimum value can be set to the next step value so that the LBT can be performed. The common value is applied according to CWp sizes allowed in each channel access priority class. However, as in the case of DL, when the maximum CWmax, p value in the channel access priority class is repeatedly maintained K times set by the base station, CWp Value to the CWmin, p value in the channel access priority class. Where K is {1, 2, ... , 8}. &Lt; / RTI &gt; Through RRC configuration, base station transmits {1, 2, ... , 8}.

In a case where a base station performs mulitple subframe scheduling for a UE as a method for adaptation of CWS in performing cat-4 LBT for PUSCH transmission on an LAA SCell,

As a behavior of the base station, the BS may signal or indicate the location of the reference subframe in the reference scheduled burst that the UE can use to update the CWS. This is an LBT type and can be included in the UL grant and transmitted through it when the cat-4 LBT is implicitly or explicitly signaled to the terminal. The base station may signal the base station if no reference subframe is detected in the base station.

Here, the reference scheduled burst refers to the most recently consecutively scheduled UL subframe (s) for the UE, which is the UL subframe (s) expected to start the Cat-4 LBT later and at least the subframe Means at least four subframes that are expected to finish transmission early in the UL subframe (s).

Here, the reference subframe refers to the first subframe in the reference scheduled burst in which the eNB successfully decodes at least one transport block from the UE on the LAA SCELL.

As a method of signaling the position of a reference subframe within a reference scheduled burst to a terminal, the embodiment first sets a bit number according to the number of subframes that have been multi-subframe schudling, In another embodiment, the position of the reference subframe can be indicated including a case where no reference subframe is detected in the bit map regardless of the number of subframes that are multi-subframe schured (eg, 0000: no reference the second subframe, the second subframe, and the fourth subframe, 0001: the 4th subframe). On the other hand, since the number of schedulable maximum subframes is four subframes, There may be a way to specify the location of the reference subframe, or as another example, if no reference subframe is detected A method of signaling 5 states (eg, "no reference subframe", "first subframe", "second subframe", "third subframe", "fourth subframe") in 3 bits Can be considered.

When the UE receives the position of the reference subframe from the BS as a behavior of the UE, the UE transmits a subframe (eg, a first subframe) within the reference scheduled burst before the subframe position of the received reference subframe For example, if UL subframe is transmitted in the first subframe among four consecutive UL subframes, the UL transmission is not received on the corresponding subframe in spite of the UE transmitting first, , The UE shall cause the CWS (s) for all channel access priority classes (or LBT priority classes) to be doubled or increased.

When the UE receives the position of the reference subframe from the BS as a behavior of the UE, the UE transmits a subframe in the reference subframe in the reference scheduled subframe in the subframe of the reference subframe (for example, the second subframe of the four consecutive UL subframes) For example, if a UL subframe is transmitted at a third of four consecutive UL subframes as an example, the terminal may maintain CWS (s) for all channel access priority classes (or LBT priority classes) without changing. It is considered that the UL transmission on the subframe is received even though the UE transmits it later, and this is set to unchange the CWS considering the transmission irrespective of the collision in the base station reception for the UL transmission.

As a behavior of a terminal, a terminal receiving a reference subframe position from a base station receives a subframe location of the reference subframe (eg, one of four consecutive UL subframes) For example, if a UL subframe is transmitted in one of four consecutive UL subframes, in this case, the UE performs UL transmission in the same subframe and the base station successively decodes the UL transmission on the corresponding subframe by at least one transport block It is determined that the base station has successfully received the UL transmission, and the UE resets CWS (s) for all channel access priority classes (or LBT priority classes) to a minimum value.

This method can be applied to the case of scheduling a single subframe.

In case DL channel access priority class 4 is directly used, if 6 is indicated as a common value and the transmission of the next PUSCH is intended for transmission with a priority class of 1, considering that the maximum CW is repeated 6 times, If the CWp value is repeatedly set K times, the CW value of the PUSCH for the corresponding priority class 1 can be determined according to the condition that the CWp value is set to CWmin, p value in the channel access priority class. If K is 6, CWp can be set to the minimum value of CWS. If K is set to 4, it is set to CWp maximum value. Or, since the common value is larger than the set K value, CWp is set to CWS of minimum value. A method of allowing the user to make a request is also considered.

Alternatively, the step of allowed CWp size for UL PUSCH transmission may be performed at the same number of steps for all channel access priority classes (for example, one of {2, 3, 4, ..., 8 steps} And the common value of the CWS is informed to the UE by the BS regardless of the priority class so that the UE receiving the common value can use the CWS corresponding to the common value according to the channel access priority class to be transmitted So that the LBT performing the back-off can be performed. This can be a method to reduce the signaling overhead for the CWS indication and to control the increase or reset of the CWS for CWS adaptation according to each channel access priority class equally by the common value. That is, when receiving the common value of the condition that the CWS increases for all the classes, the corresponding CWS is set to increase equally regardless of the priority class to be transmitted in the terminal, and in the resetting of the CWS, If the common value is received or the reset condition by the K iteration is satisfied, the CWS of the corresponding CWS is set to reset regardless of the priority class. This can be considered as a way to reduce the signaling overhead for CWS among the LBT parameters transmitted in the UL grant. Hereinafter, a method of setting the allowed CWp sizes to two levels based on the channel access priority class used in the DL as one embodiment may be used. In this case, the signaling overhead of the common value indicating CWS is 1 bit.

A more general expression of allowed CWp size would be:

D, E, F, G and H can be set to values satisfying the condition A <B = <C <D = <E <F = F, and H can be set as the maximum CW size value of the corresponding channel access priority class. For example, if the maximum allowed CW size is set to {7,15,31,63,127,255,511,1023} set to use the value used in the DL, the maximum allowed CW size is set to {7,15,31,63,127,255,511 , 1023} can be set so that each of B, D, F, and H can have a value.

As another example, when the UL transmission is set to use a small CW size compared to the DL transmission, for example, if the maximum allowed CW size is {3,4,5,6} or {3,4,5,6, 7}, the UL PUSCH transmission is performed even when the maximum CWS defined by one of {3,4, 5, 6} or one of {3,4,5,6,7} The allowed CWp size step for all channel access priority classes can be set to the same number of steps.

In the following, a method of setting the steps of the allowed CWp sizes as two steps may be used as one embodiment.

Here, B, C, and D values can be set to values satisfying the condition A <B = <C <D, and B and D values can be set as the maximum CW size value of the corresponding channel access priority class. For example, if the maximum allowed CW size is set to {3,4,5,6} or {3,4,5,6,7}, the maximum allowed CW size is set to {3,4,5,6} It is possible to set one value or one of {3,4,5,6,7} to have each of B and D.

D, E, F, G and H can be set to values satisfying the condition A <B = <C <D = <E <F = F, and H can be set as the maximum CW size value of the corresponding channel access priority class. For example, if the maximum allowed CW size is set to {3,4,5,6} or {3,4,5,6,7}, the maximum allowed CW size is set to {3,4,5,6} It is possible to set one value or one of {3,4, 5, 6, 7} to have each of B, D, F, and H.

Each UE can update and adapt CW using new data indication (NDI) information included in UL grant. When the transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe indicates the new data indication, the NDI is toggled in the UL grant received in the n th subframe from the base station, the CW Reset, that is, CW_min value to set the current CWp. If the NDI does not indicate a new data indication in the UL grant received from the base station from the n th subframe and retransmission of the PUSCH in the (n-4) th UL subframe is instructed and the NDI is not toggled, At this point, the current CW is doubled and the LBT is performed using the CW doubled as the CW value for transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe. Also, LBT to CW_max value by retransmission is calculated by K = {1, ... , 8}, the CWp is set to the CW_min value.

In the case where the base station manages only the CW for the base station transmission without information on the CW of the UE and each UE (s) manages the CW, the method of updating and adapting the CW of each UE (s) Each UE can update and adapt CW using new data indication (NDI) information included in the UL grant. If the transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe indicates a new data indication, the NDI is toggled from the base station to the UL grant in the nth subframe from the base station, and the CW for the UE is reset , That is, CW_min value to set the current CWp. If the NDI is not toggled by instructing retransmission of the PUSCH in the (n-4) th UL subframe without NDI indicating the new data indication in the UL grant in the nth subframe from the base station, And performs LBT using the doubled CW as the CW value for transmission of the PUSCH scheduled to the UE in the (n + 4) th subframe by doubling the current CW. Also, LBT to CW_max value by retransmission is calculated by K = {1, ... , 8}, the CWp is set to the CW_min value.

In yet another embodiment, the same HARQ process id transmitted prior to the UL grant received in the n th subframe is indicated from the base station, the NDI is toggled, and the transmission of the scheduled PUSCH to the UE indicated by the corresponding UL grant indicates a new data indication , The CW for the corresponding UE is reset at the time of receiving the UL grant, that is, the current CWp is set to the CW_min value. If the same HARQ process id is indicated in the UL grant received from the base station from the n th subframe and the NDI does not indicate the new data indication and the NDI is not toggled by instructing the retransmission for the PUSCH in the preceding UL subframe, grant the CW to the corresponding UE in the subframe indicated by the corresponding UL grant as the CW value for transmission of the scheduled PUSCH, and then increase the current CW or the doubled CW To perform the LBT. Also, LBT to CW_max value by retransmission is calculated by K = {1, ... , 8}, the CWp is set to the CW_min value.

When the UE adjusts the contention window size according to the toggle of the NDI included in the UL grant as a method of adapting the CWS, the UE applies the adaptation of the CWS as soon as possible according to the UL channel conditions transmitted by the UE . The subframe of the most recent UL transmission burst successfully transmitted by the UE is referred to as a reference subframe. 2. The starting subframe of the UL transmission burst that is expected to be used by the cat-4 LBT type in the UE is set as a reference subframe, The CWS may be reset on the basis of the successful decoding of the reference subframe or may be set to increase the CWS if the decoding can not be successfully performed. In this case, if at least one of the transport blocks (s) in the reference subframe is successfully decoded, the CWS is reset for all priority classes. Otherwise, all priority classes are incremented to the next higher CWS value Setting. Also, the UE can determine whether the transmission of the reference subframe in the first or second subframe is successful or not based on the value of the NDI (new data indicator) transmitted by the UL grant by the BS, If the NDI for TB is also toggled, it is determined as a new data indication to reset the CWS for all priority classes. Otherwise, all priority classes are set to be increased to the next higher CWS value. Also, LBT to CW_max value by retransmission is calculated by K = {1, ... , 8}, the CW_min value should be set only for CWp for the corresponding priority class.

When the terminal sets a subframe of the most recent UL transmission burst successfully transmitted by the UE as a reference subframe and the UE sets CWS to the next higher level or reset the CWS in the cat-4 LBT based on the NDI of the reference subframe, Since UL transmission in Scell is not synchronous HARQ but asynchronous HARQ, UL grant that is not toggled with NDI, which can refer to retransmission for uplink transmission in subframe n, is transmitted in subframe (n + 4) Can not be guaranteed. Therefore, when the UL grant is not received in the corresponding subframe (n + 4), ambiguity occurs as to whether CWS should be reset or increased to the next level when using CWS for cat-4 LBT in the terminal. Therefore, if the UL grant for a TB of one of the TBs (s) is toggled based on the NDI in the recently received UL grant in the UE, the CWS for all the priority classes is received reset it to CW_min, otherwise set it to increase to the next higher level CWS value for all priority classes. Also, LBT to CW_max value by retransmission is calculated by K = {1, ... , 8}, the CW_min value should be set only for CWp for the corresponding priority class.

The present invention relates to a CWS adaptation method in UL LBT for UL PUSCH transmission in a terminal. The present invention relates to a method for defining a reference subframe used for updating a CWS in CWS adaptation during a UL LBT procedure to perform UL transmission in more detail and solving a mismatch between a terminal and a base station for a reference subframe.

First, the base station can be scheduled according to various methods. 30 is a diagram illustrating a method of scheduling a UL subframe (s) of a UL transmission burst to a UE by a base station without scheduling an LBT gap between consecutive UL subframes (s) of the UL transmission burst to the UE to be.

FIG. 30- (a) is a flowchart illustrating a method for determining CWS in a subframe for which Cat-4 is to be performed for UL transmission (S3010). Each UL scheduled subframe of the most recent UL transmission burst is divided into UL subframes gap. In this case, if the cat-4 LBT in the first subframe of the UL transmission burst is succeeded, if a continuous subframe without a gap is scheduled to the same UE, the UL subframe is continuously transmitted without additional LBT If the cat-4 LBT in the first subframe is unsuccessful, the LBT in the corresponding subframe is performed according to the LBT type signaled from the base station in each subframe. Giving each UL grant to the same terminal on a subframe may be a method that can avoid a failure to transmit UL transmission due to missed UL grant or UL transmission that has been continuously scheduled due to UL LBT failure .

FIG. 30- (b) is a flow chart for determining a CWS in a subframe for which Cat-4 is to be performed for UL transmission (S3020). The UL transmission burst is UL grant for scheduling one multiple subframe 4 LBT in the first subframe of the UL transmission burst in case of success, the transmission to multiple subframes is performed in case of cat-4 LBT in the first subframe of the UL transmission burst. Otherwise, the cat-4 LBT is transmitted in the scheduled multiple subframes. If the UL subframe succeeds before the second subframe, UL transmission is performed according to the UL grant continuously in the second and third UL subframes.

FIG. 30- (c) is a flowchart illustrating a method for determining CWS in a subframe for which Cat-4 is to be performed for UL transmission (S3030). Each UL scheduled subframe of the most recent UL transmission burst is transmitted to each UL grant is performed without gap between UL subframes. In this case, when a cat-4 LBT in the first subframe of the UL transmission burst is succeeded, if consecutive subframes without a gap are scheduled to the same UE, If the cat-4 LBT in the first subframe does not succeed, the LBT in the corresponding subframe is performed according to the LBT type signaled from the base station in each subframe. Giving each UL grant to the same terminal on a subframe may be a method that can avoid a failure to transmit UL transmission due to missed UL grant or UL transmission that has been continuously scheduled due to UL LBT failure .

31 is a diagram illustrating an embodiment in which a BS schedules a UL subframe (s) of an UL transmission burst to a UE. The BS performs UL subframe (s) of an UL transmission burst on a UL subframe and a method of scheduling with a gap

FIG. 31- (a) illustrates a method for determining a CWS in a subframe in which Cat-4 is to be performed for UL transmission in step 3110. In step 3110, each UL scheduled subframe of the most recent UL transmission burst is scheduled by each UL grant, And is scheduled with a gap. In this case, each UL subframe configured to perform each cat-4 LBT due to a gap between UL subframes may be regarded as an UL transmission burst.

FIG. 31- (b) is a flow chart illustrating a method of determining a CWS in a subframe in which Cat-4 is to be performed for UL transmission (S3120). The UL transmission burst includes a UL gap between UL subframes by UL grant for scheduling a multiple subframe 4 LBT in the first subframe of the UL transmission burst, the transmission to multiple subframes is performed. If not, the cat-4 LBT If the UL subframe succeeds before the second subframe, UL transmission is performed according to the UL grant continuously in the second and third UL subframes.

FIG. 31- (c) is a flowchart illustrating a method of determining CWS in a subframe for which Cat-4 is to be performed for UL transmission (S3130). Each UL scheduled subframe of the most recent UL transmission burst is allocated to one UL grant for multiple subframe scheduling Or when a UL scheduled subframe of the most recent UL transmission burst is scheduled by one UL grant for multiple subframe scheduling from one DL subframe and scheduling is performed with a gap between UL subframes . In this case, each UL subframe configured to perform each cat-4 LBT due to a gap between UL subframes may be regarded as an UL transmission burst.

Also, the reference subframe of the latest UL transmission burst used for updating the CWS in CWS adaptation during the UL LBT procedure can be defined according to various embodiments as follows.

In one embodiment, the Reference subframe sets the start transmission subframe of the latest UL transmission burst in which a Cat-4 LBT procedure is expected to be used as a reference subframe for updating the CWS. This means that the transmission of the UL DMRS or SRS from the UE is detected in the base station and the decoding of the PUSCH is completed.

In another embodiment, the Reference subframe sets the start transmission subframe of the latest UL transmission burst in which the Cat-4 LBT procedure is expected to be used as a reference subframe for updating the CWS.

In another embodiment, the reference subframe is set to the first subframe in the reference scheduled burst in which the eNB successfully decodes at least one transport block from the UE on the LAA SCELL. Here, the reference scheduled burst refers to the most recently consecutively scheduled UL subframe (s) for the UE, which is the UL subframe (s) expected to start the Cat-4 LBT later and at least the subframe Means the UL subframe (s) expected to finish transmission before at least four subframes.

In another embodiment, the reference subframe may be defined as a subframe or a starting subframe of the most recent UL transmission burst that the UE successfully transmitted.

In another embodiment, the reference subframe may be defined as a subframe or a start subframe of the most recent UL transmission burst successfully transmitted after the UE performs Cat-4.

30 to 31 and sets a reference subframe for updating the CWS, the UE performs UL LBT for the reference subframe according to the scheduling information transmitted in the UL grant from the base station And if the LBT is successful, UL transmission is performed in the corresponding UL reference subframe. However, according to the channel interference condition of the license-exempt band used by the LAA SCell, the base station may not be able to detect the signal even though the terminal transmits the signal. In this case, the BS determines whether the UL transmission of the scheduled UL subframe is due to UL LBT failure of the UE or a transmission failure at the UE, or if the UE missed the UL grant from the BS and failed to transmit the UL grant Or even if the terminal has transmitted it, it can not accurately determine whether the base station can not detect it due to channel interference in the corresponding subframe. In particular, if the reference subframe according to the above embodiment of the present invention is transmitted in the UL transmission burst transmitted from the UE to the reference subframe but the BS can not detect it, the contention window size must be increased. However, If it is understood, CWS may be reset even though it is an increase condition of CWS. Or vice versa. Accordingly, in determining CWS for a UL LBT performed in a mobile station, a base station and a mobile station solve a mismatch problem for a reference subframe in a base station and a mobile station for adjusting CWS, So that the reference subframe of the UL transmission burst received by the base station can be known to be a reference subframe transmitted by the UE.

In the following description of the present invention, the initial transmission subframe of the UL transmission burst that performed the cat-4 LBT transmitted from the UE in the reference subframe is referred to as a starting transmission subframe of the UL transmission burst in the UE And a method for setting the first subframe of the UL transmission burst received at the base station so as to know whether the first subframe transmitted by the UE is known.

32 is a diagram illustrating a structure for UL radio frame, UL subframe, and UL slot in a subframe in LTE. In the LTE, the cyclic shift index of the sequence of the reference signal (UL DMRS) in the UL subframe is determined by a function of a cyclic shift index of the UL DMRS in the UL grant transmitted from the base station to the UE, a value set by the RRC signaling, . The cyclic shift value determined by the RRC signaling during a certain time period is the same and the cyclic shift index value determined by the UL grant is constant within one subframe. Therefore, the cyclic shift value of the UL DMRS in one subframe is The slot index can be used to determine different values.

Method P) Unlike the method of using the cyclic shift index of the sequence of the UL DM-RS transmitted in the UL subframe transmitted as the first of the UL transmission burst transmitted after the UL LBT based on the slot index used in the legacy A method of transmitting a sequence of UL DM-RS using the same method as the following embodiments can be considered. Therefore, the base station performs detection of the UL DMRS twice at the time of PUSCH detection for each subframe of the UL transmission burst scheduled by the base station, so that each subframe of the received UL transmission burst is a subframe that is successfully transmitted from the terminal, The base station determines whether there is a subframe transmitted successfully by the mobile station before the transmission of the subframe.

- Method P-1) In one embodiment, the UE sets the cyclic shift index of the UL DM-RS sequence transmitted in the UL subframe transmitted in the first transmission of the UL transmission burst to the UL subframe The UL DMRS transmitted in the 1st slot by switching the 1st slot index and the 2nd slot index between the slots by cyclically shifting the cyclic shift index of the UL DMRS transmitted in each slot to the cyclic shift of the DMRS sequence based on the 2nd slot index And the UL DMRS transmitted in the 2nd slot is configured to transmit the UL subframe including the UL DMRS by setting the cyclic shuffle of the DMRS sequence based on the 1st slot index.

When the UE transmits a UL subframe to the base station, the UL subframe indicates whether the UL subframe is the first UL subframe of the UL transmission burst scheduled from the base station, and the cyclic shift index of the UL DMRS is switched between the slots. It can be used as a method to prevent mismatch to the start transmission UL subframe.

The base station uses the UL DMRS generated by two methods (ie switching or no switching of the UL DMRS cyclic shift value between the slots) until the UL subframe of the UL transmission burst scheduled by the base station becomes the PUSCH detection of the UL subframe And if the UL PUSCH is detected by the switched DMRS, the transmission of the corresponding subframe is determined to be the first UL subframe of the UL transmission burst in the UE. At this time, according to the success of the PUSCH decoding in the first UL subframe, the CWS is reset or the CWS increases to the next higher value by signaling (for example, UL grant, common control channel, common PDCCH) . In contrast, when the UL PUSCH is detected by the non-switched DMRS in the base station, the transmission of the corresponding subframe is not the transmission of the first UL subframe of the UL transmission burst at the terminal, and the first UL subframe of the UL transmission burst at the terminal is The base station determines that the first UL subframe can not be detected by the interference condition of the channel, and the base station signals the UE to increase the CWS to the next higher value (for example, UL grant, common control channel, common PDCCH) It can be instructed through.

- Method P-2) As another embodiment, a method may be considered in which the cyclic shift index of the UL DMRS sequence in the 1st slot and the cyclic shift index of the UL DMRS sequence in the 2nd slot are set along the same slot index. There may be a method of setting the same cyclic shift index of the UL DMRS sequence based on the index of the 1st slot of the UL subframe to be transmitted and setting the same cyclic shift index of the UL DMRS sequence based on the index of the 2nd slot There can be a way.

When the UE transmits a UL subframe to the BS, it is determined whether the UL subframe is the first UL subframe of the UL transmission burst scheduled from the BS and the cyclic shift index of the UL DMRS is generated based on the same slot index in the same subframe between the slots It can be used as a method for preventing mismatch of the UL subframe of the start transmission and the terminal of the base station.

The BS determines whether the UL subframe of the UL transmission burst scheduled by the base station is set based on a value or a slot index of the same slot index of the UL DMRS cyclic shift value between the slots until the PUSCH detection of the UL subframe is performed Value), if the UL PUSCH is detected by the DMRS generated by the value of the same slot index of the UL DMRS cyclic shift value between the slots, the detection of the corresponding subframe The transmission is judged to be the UL subframe at the beginning of the UL transmission burst in the UE. At this time, according to the success of the PUSCH decoding in the first UL subframe, the CWS is reset or the CWS increases to the next higher value by signaling (for example, UL grant, common control channel, common PDCCH) . In contrast, when the UL PUSCH is detected by the UL DMRS generated by the value based on the slot index in the base station, the transmission of the corresponding subframe is not the transmission of the first UL subframe of the UL transmission burst at the terminal, the first UL subframe of the transmission burst is transmitted from the UE but it is determined that the first UL subframe can not be detected by the interference condition of the channel, so that the BS signals the UE to increase the CWS to the next higher value (for example, UL grant , common control channel, common PDCCH).

- Method P-3) As another embodiment, the UL DMRS of the UL subframe that the UE first transmits the cyclic shift index of the pre-defined UL DMRS sequence based on the predefined index of the cyclic shift of UL DMRS set in the base station and the UE A method in which the data is transmitted and applied can be considered.

Method Q) Based on the slot index used in the legacy, the cyclic shift index of the sequence of the UL DM-RS transmitted in the UL subframe (s) excluding the first transmitted UL subframe of the UL transmission burst transmitted after the UL LBT The UL DM-RS sequence is generated and transmitted using the same method as in the following embodiments, so that it is possible to distinguish the first start transmission and the non-initial transmission of the UL transmission burst at the base station.

-Method Q-1) In one embodiment, the UE sets a cyclic shift index of the UL DM-RS sequence transmitted in the UL subframe excluding the UL subframe transmitted in the first transmission of the UL transmission burst, The UL DMRS, which is transmitted in the first slot by switching the cyclic shift index of the transmitting UL DMRS between the slots, that is, switching the 1st slot index and the 2nd slot index, sets the cyclic shift of the DMRS sequence based on the 2nd slot index, The UL DMRS transmitted in the slot is configured to transmit the UL subframe including the UL DMRS by setting the cyclic shuffle of the DMRS sequence based on the 1st slot index.

-Method Q-2) As another embodiment, the UE transmits a UL subframe (UL subframe) excluding the UL subframe transmitted in the first UL transmission burst, a cyclic shift index of the UL DMRS sequence in the 1st slot, A method of setting the cyclic shift index of an existing UL DMRS sequence along the same slot index can be considered. There may be a method of setting the same cyclic shift index of the UL DMRS sequence based on the index of the 1st slot of the UL subframe to be transmitted and setting the same cyclic shift index of the UL DMRS sequence based on the index of the 2nd slot There can be a way.

-Method Q-3) In another embodiment, the UE determines the pre-defined index of the cyclic shift of the UL DMRS set in the UL subframe (s) except for the UL subframe transmitted in the first transmission of the UL transmission burst, a method may be considered in which the cyclic shift index of the -defined UL DMRS sequence is applied to the UL DMRS of the UL subframe to which the UE first transmits.

FIG. 31 shows a case where CWS in a subframe for which Cat-4 is to be performed for UL transmission is determined. In the case where each UL scheduled subframe of the most recent UL transmission burst has a gap between successive subframes and is scheduled by each UL grant 31 (a)) and scheduling with a gap between consecutive UL subframes scheduled while receiving multiple subframe scheduling from one DL subframe (FIG. 31 (b)) and multiple UL grants from one DL subframe (FIG. 31- (c)) while scheduling with a gap between UL subframes. In this case, each UL subframe carrying each cat-4 LBT due to a gap between UL subframes can be regarded as an UL transmission burst. 31, when determining the CWS for performing cat-4 for the next UL transmission, the most recent UL transmission burst for performing cat-4 as the reference subframe is as shown in FIG. 31 (UL SF # (n + 5 + k)) or C subframe (n + 4 + k) in the subframe UL SF # (n + 6 + k)). In this case, since the subframe carrying each cat-4 transmitted from the back may be the subframe of the most recent UL burst, the first of the subframes scheduled due to the LBT success in the preceding UL cat-4 LBT Even if the UL subframe is started, the first start subframe of the UL burst is informed through the methods P-1, P-2, P-3 and Q-1, Q-2 and Q-3 in the corresponding subframe It is difficult to solve the mismatch of the reference subframe for adjusting the CWS for the next UL transmission between the BS and the MS. In this case, since detection of the UL DMRS and the PUSCH twice in the BS can increase the detection complexity of the BS only, Q-1, Q-2, Q-3, and Q-3 of the sequence of UL DMRS at the UE in order to perform scheduling with UL gap Do the same thing So that there is from the base station can give way signaling to the mobile station can be considered. The signaling method may be, for example, instructed via an UL grant, a common control channel, or a common PDCCH. 30, when the scheduling for the UL transmission burst from the base station is scheduled without a gap, the base station transmits the method P-1, P-2, P-3 and the methods Q- 31, when the scheduling of the UL transmission burst is scheduled with a gap as shown in FIG. 31, the BS transmits a method P-1, P-2, P-3, and methods Q-1, Q-2, and Q-3 so that the number of blind detection at the base station can be reduced.

As another embodiment of the present invention, FIG. 33 shows a case of receiving an LBT type change signaling. FIG. 33- (a) shows a case in which a Cat-4 LBT is signaled by signaling an UL grant, FIG. 33- (b) shows a case in which a Cat-4 LBT is signaled by UL grant signaling, And receiving change-related signaling. As shown in FIG. 33, when the LBT type for the UL subframe of the UL transmission burst is changed to the LBT (for example, 25us LBT) or cat-2 LBT having a single interval in the UL LBT cat- In the case of performing 25us LBT or cat-2 LBT, it is desirable that the success / failure of the preceding UL transmission performing the 25us LBT in the CWS adjustment of the UL transmission burst performing the next cat-4 is adjusted so that the CWS is adjusted . Although Cat-4 LBT is signaled by UL grant, if 25us LBT or cat-2 LBT is performed without performing Cat-4 for UL transmission by signaling from the base station in the middle, Is not reflected. However, when transmitting a UL grant, the base station informs the LBT type to perform the Cat-4 LBT and the terminal receives the corresponding UL grant. However, when the LBT type is changed as shown in FIG. 32- (b) If the terminal does not receive the change signaling of the LBT type, the base station expects to receive the LBT type change by signaling the LBT type change signal, but the terminal performs cat-4 LBT without changing the LBT type. In this case, the UE indicates that the cat-4 LBT has been performed, and transmits the UL DMRS through the UL transmission in the same manner as in the methods P-1, P-2, and P- The UL subframe can be recognized as a subframe performing cat-4 LBT. When the terminal receives the latest change signaling of the LBT type, the UL DMRS does not perform the setting in the same manner as in the method of the method P-1, P-2, P-3, The UE transmits to the BS the UL subframe transmission that is a transmission of an LBT having a single interval (for example, 25us LBT) or a cat-2 LBT (Eg, 25us LBT) or cat-2 LBT with a single interval in the CWS adjustment of the UL transmission burst performing cat-4, so that the success / failure of the transmitted UL subframe is not used Can be set.

(About UL LBT failed procedure)

The present invention relates to the behavior of the UE (s) in case the UE (s) fails the LBT and the base station transmits the UL grant (s) for the scheduled PUSCH to the UE (s) After a UE (s) performs a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1) or cat-4 based LBT for transmission of PUSCH, LBT the behavior procedure of the terminal in case of failing is explained.

When a UE is scheduled to perform UL transmission continuously, that is, when a UL grant (s) included in a control channel of each DL subframe is transmitted to a UE from a continuous multiple DL subframe, or when multi there may be a case where continuous UL transmission is performed through one UL grant included in a control channel of one DL subframe by -subframe scheduling. In these cases, in a case where a continuous UL subframe is scheduled to the same UE as an embodiment of the present invention, the LBT (eg, 16us, 25us, 34us, 43us or 16 + 9 * N, N may be a natural number greater than or equal to 1), or cat-4 based LBT fails, UL scheduling in the corresponding UL subframe may result in scheduling in the corresponding UL subframe according to the result of LBT failure for the corresponding UL subframe The UL transmission in the next subframe can be configured to transmit the reservation signal so that the UL transmission in the next subframe can be determined through the LBT in the next subframe. A method may be considered in which the Reservation signal is transmitted until the LBT point of time of the next subframe that is scheduled to determine whether to perform UL transmission depending on the LBT in the next UL subframe. As an embodiment of the reservation signal transmission method, a method of transmitting a reservation signal only to a subset of resources that can be transmitted due to an LBT failure although being scheduled for UL transmission may be considered. Alternatively, A method may be considered in which a reservation resource is transmitted to a dedicated resource of a corresponding UL subframe by setting a predetermined dedicated resource as a known signal of the BS and the MS. This method may be applied as an operation in the MCOT set by the base station. However, considering the case of cross-DL burst scheduling, it can be applied to the operation outside the MCOT set by the base station , A continuous UL subframe may be applied if it is within the same MCOT.

In the case of UEs not scheduled at the start time of the UL subframe, the UL transmission of other UEs that are scheduled first after the transmission of the DL is scheduled to be transmitted in the nth subframe, (N + 1) th, (n + 2) th or (n + 3) th UL subframe other than the n th subframe in which the UL subframe is scheduled to be transmitted, In the case of UE # 1, it is also possible to consider a method of making a reservation signal transmission so that UL transmission in the next UL subframe can be determined through LBT in the next subframe. A method may be considered in which the Reservation signal is transmitted until the LBT point of time of the next subframe that is scheduled to determine whether to perform UL transmission depending on the LBT in the next UL subframe. As an embodiment of the reservation signal transmission method, a method of transmitting a reservation signal only to a subset of resources that can be transmitted due to an LBT failure although being scheduled for UL transmission may be considered. Alternatively, A method may be considered in which a reservation resource is transmitted to a dedicated resource of a corresponding UL subframe by setting a predetermined dedicated resource as a known signal of the BS and the MS. This method may be applied as an operation in the MCOT set by the base station. However, considering the case of cross-DL burst scheduling, it can be applied to the operation outside the MCOT set by the base station , A continuous UL subframe may be applied if it is within the same MCOT.

As another embodiment of the present invention, when the base station is scheduling UL to a plurality of UEs, information on whether a UL subframe to be scheduled at the time of transmitting an UL grant is a last UL subframe for UEs in a cell in which scheduling is performed . Therefore, it is possible to indicate through the control signaling to the UE whether the UL is a last UL subframe among the UEs that have been schduled by the corresponding BS. An indication method through control signaling may be a method of informing through a DL common control signal in a DL transmitting an UL grant or a method of indicating through a common control signal for UL in one embodiment . Alternatively, there may be a way for the base station to provide an indication of the last UL subframe in the UL grant. In case of multiple subframe scheduling, the BS can indicate that the last subframe of a multiple subframe scheduled with UL grant is the last subframe. When the UE receives information according to the indication of the last UL subframe, if the UL subframe performing the LBT for the scheduled UL transmission is the last UL subframe, if the UE fails the UL LBT (single interval LBT or Cat-4 LBT) The UL PUSCH transmission indicated by the UL grant in the corresponding UL subframe is dropped. However, if the UL subframe scheduled by the UL grant does not receive the instruction of the last subframe or is not the last subframe, transmission of the UEs scheduled in the next subframe is transmitted to the success or failure of the LBT in the next subframe by transmitting a specific reservation signal. Ensure that you can decide whether to perform.

A method may be considered in which the Reservation signal is transmitted until the LBT point of time of the next subframe that is scheduled to determine whether to perform UL transmission depending on the LBT in the next UL subframe. As one embodiment of the reservation signal transmission method, a method of transmitting only a subset of resources scheduled for UL transmission may be considered, or in another embodiment, a known signal for a reservation signal and a terminal may be preset A dedicated resource may be set up to transmit a reservation signal to the dedicated resource. This method may be applied as an operation in the MCOT set by the base station. However, considering the case of cross-DL burst scheduling, it can be applied to the operation outside the MCOT set by the base station , A continuous UL subframe may be applied if it is within the same MCOT.

As another exemplary embodiment of the present invention, the LBT for the UL transmission scheduled for the UL grant and the LBT (eg, 16us, 25us) set for the UE in the UL subframe, regardless of whether the subframe scheduling is single subframe scheduling or multiple subframe scheduling, , 34us, 43us, or 16 + 9 * N, N may be a natural number greater than or equal to 1), or cat-4 based LBT failure.

(With respect to the LBT for the PUSCH including PUCCH and UCI information)

PUCCH is used as a non-scheduled channel, unlike PUSCH, which receives scheduling information from a base station. If simultaneous transmission of PUCCH + PUSCH is configured, simultaneous transmission of PUCCH and PUSCH is possible. Otherwise, UCI information such as CQI, RI, and PMI for the DL PDSCH transmission may be piggybacked to the scheduled PUSCH and if the scheduling of the PUSCH is not scheduled from the base station, HARQ-ACK values for HARQ -ACK values and a CQI can be transmitted. Therefore, UCIs on unlicensed carriers can be transmitted on the unlicensed carrier to the uplink PUCCH or PUSCH. In this case, the LBT method of the PUSCH including the PUCCH or UCI in the unlicensed carrier is set as follows, LBT can be performed.

First, in case of transmitting the ACK, NACK, NACK / DTX and DTX values as the HARQ-ACK for the PUCCH and transmitting the periodic CSI and the HARQ-ACK values in one PUCCH format, periodic CSI may be transmitted at the same time. The values as HARQ-ACK for the PDSCH may be the most priority information that should be fed back to the base station in terms of DL throughput and may precede the priority of the periodic CSI values for link adaptation. Therefore, in the case of non-scheduled PUCCH, (E.g., 16us, 25us, 34us, 43us or 16 + 9 * N, where N may be a natural number equal to or greater than 1) as a fast channel access when HARQ-ACK for the PDSCH is included in the PUCCH transmitted from the BS. , Or a method of performing channel access using the highest priority class in the channel access priority class (eg, channel access priority class # 1). In addition, when only CQI is transmitted to the PUCCH, it can be configured to perform cat-4 LBT. This is because the channel state information (CSI) in the unlicensed carrier may not be significant in the CSI under the condition that channel access is not guaranteed.

In addition, the LBT method of the PUSCH can be set according to whether the HARQ-ACK value is included in the UCI for the PUSCH including the UCI. When the HARQ-ACK for the PDSCH is included in the PUSCH including the UCI, the UE may use a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * ) Or a method of allowing channel access to be performed based on a class having the highest priority in the channel access priority class (eg, channel access priority class # 1). In addition, when only CQI is transmitted to the PUSCH, it can be configured to perform cat-4 LBT. However, in the case of the PUSCH including the UCI, when an UL grant for performing scheduling of the PUSCH is transmitted in the DL transmission, the LBT is performed in advance and the LBT of the PUSCH according to the LBT method used for transmission of the UL grant, If the PUSCH LBT is to be transmitted using fast channel access, the transmission of the PUSCH including UCI should be performed by overriding the corresponding LBT method. If not, the fast channel UL LBT and HARQ-HARQ, which are set depending on the UL grant only for transmission of the PUSCH having the UCI including the HARQ-ACK, can be configured to perform transmission of the PUSCH with the UCI using the LBT method capable of access, A predetermined LBT for transmission of a PUSCH having a UCI including an ACK, a PUSCH having a UCI including a HARQ-ACK using a LBT method capable of fast channel access, Can be set to perform transmission.

(PDCCH order in Random Access procedure, PRACH and LBT for RAR)

In case of triggering non-contention-based PRACH transmission by PDCCH order, the PDCCH transmitted to UE in order to set up LBT for PDCCH to trigger UL synchronization is a single interval LBT (eg 16us (Eg, 25us, 34us, 43us, or 16 + 9 * N, N can be a natural number greater than or equal to 1) or by assigning the highest priority class in the channel access priority class as the channel access priority class # A method of allowing access to the channel for the channel can be considered. In case of carrying the PDCCH and the PDSCH for the same UE or another UE (s) in the DL subframe including the PDCCH for PRACH triggering, the LBT parameter according to the channel access priority class set for the corresponding PDCCH / PDSCH transmission eg, m_p, CW_min, CW_max, T_mcot, and allowed CW_p sizes.

Next, PRACH is a random access preamble channel. It is considered as the highest priority channel when the UE is a power limitation in CA (Carrier Aggregation). Therefore, the PRACH is different from other UL channels (eg PUCCH, PUSCH with UCI, PUSCH w / o UCI) and the signal (eg, a sounding reference signal), the transmission power of the PRACH is guaranteed to be the highest priority, or other UL channels or signals may be dropped to guarantee transmission of the PRACH. Therefore, if the PRACH transmission is configured, there may be a method of setting to be transmitted without LBT as fast channel access. If PRACH transmission fails due to LBT, the UE can not guarantee uplink transmissions because it can not synchronize on unlicensed carriers. This can increase unnecessary latency considerably. Therefore, LBT for PRACH It is possible to set the terminal to perform transmission to the base station without performing the transmission. Or by using a single interval LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than or equal to 1) or the highest priority class in the channel access priority class class # 1) to perform channel access to the PRACH.

With respect to the random access response (RAR), after transmitting the random access preamble as described above, the terminal attempts to receive its random access response in the random access response reception window indicated by the system information or the handover command . A random access response (RAR) is transmitted in the form of a MAC PDU, and the MAC PDU is delivered to the PDSCH. The PDCCH is also transmitted together with the PDSCH to properly receive the information transmitted on the PDSCH. The PDCCH includes information of a UE to receive the PDSCH, frequency and time information of the PDSCH, and a transmission format of the PDSCH. Once the UE succeeds in receiving the PDCCH to itself, it appropriately receives the random access response transmitted on the PDSCH according to the information of the PDCCH. The random access response includes a random access preamble identifier, an UL grant, a temporary C-RNTI (Temporary C-RNTI), and a time alignment correction value (Time Alignment Command). The random access preamble identifier is necessary because random access response information for one or more UEs can be included in one random access response. Therefore, the uplink grant, the temporary C-RNTI, To indicate if it is valid. Unlike the contention-based random access procedure, the non-contention-based random access procedure determines that the random access procedure has been normally performed by receiving the random access response information, and terminates the random access procedure. Further, the non-contention-based random access procedure may be performed in the case of the handover process and in the case of being requested by the base station. For a non-contention-based random access procedure, it is important to receive a dedicated random access preamble from the base station that has no possibility of collision. As a method for receiving the random access preamble, there are a handover command and a PDCCH command. In addition, the BS may set a PRACH resource in which the UE transmits the random access preamble. The PRACH resource includes a subframe and a frequency resource used by the UE for random access preamble transmission. Table 10 below shows the PRACH mask indexes for the base station to set the PRACH resource to the UE. For example, in the FDD mode, the UE may transmit a random access preamble (Random Access Preamble) in only one subframe among 10 subframes, an even subframe, or an odd subframe, according to a PRACH mask index Lt; / RTI &gt;

Table 10

In such a random access procedure, the RAR in the contention-based or non-contention-based random access procedure is delivered to the UE through the PDSCH. Therefore, if there is a PDSCH to transmit to other UEs except for a case where RAR is independently transmitted, the LBT parameter is applied according to the channel access priority class set by the BS in order to transmit the corresponding PDSCH (s) The PDCCH / PDSCH for the RAR transmitted to the UE in order to prevent unnecessary latency due to the random access procedure in the case where the RAR is independently transmitted without PDSCH transmitted to other UEs, (eg, channel access priority class # 2) using the LBT (eg 16us, 25us, 34us, 43us or 16 + 9 * N, where N can be a natural number greater than 1) 1) to perform channel access to the PDCCH / PDSCH for the RAR.

The present invention can be applied to a case where the UE can transmit UL, ACK, NACK, NACK / DTX, and DTX values on the unlicensed carrier as HARQ ACKs for the PDSCH (s) A method of performing CW update and adaptation for DL transmission in a base station will be described.

(In the case where the HARQ-ACK for the PDSCH (s) transmitted to the DL on the LAA Scell is transmitted only to the UL on the unlicensed carrier, LAA SCell)

When the HARQ-ACK for the PDSCH (s) transmitted to the DL on the unicensed carrier, LAA Scell, is transmitted to the unlicensed carrier only in the UL on the LAA SCELL, the HARQ-ACK (s ), The BS sets the contention window (CW) for the DL PDSCH (s) transmission in the LAA SCell to be reset, and if not, doubles the CW. That is, if the base station detects at least one ACK from the UE for the PDSCH (s) transmitted from the base station after successful decoding of the PUCCH or PUSCH including the HARQ-ACK transmitted from the UE on the LAA SCell, The base station determines that the channel for the medium between the base station and the terminal is idle, and the CWp (p = {1,2,3,4), which may be differently set according to the channel access priority class, } May be reset to CWmin and decoding of the PDSCH (s) in the UE according to the corresponding PDSCH transmission may fail, so that the UE transmits a feedback in the NACK so that the NACK or NACK / DTX or DTX is detected Or determines that the corresponding base station doubles the CW. The base station doubles the CW even in the case of NACK or NACK / DTX or DTX detection in the base station, which may occur due to transmission of PUCCH or PUSCH including HARQ-ACK transmitted from the UE in the unlicensed carrier. In this case, the base station determines that the channel for the medium between the BS and the MS is busy, and thus the CWp (p = {1,2,3,4}), which may be differently set according to the channel access priority class, Set CWp to doubling. Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

When the number of unlicensed carriers increases, it may not be possible to transmit the HARQ-ACK value only to the UL of a specific unlicensed carrier. In addition, HARQ-ACK transmission may be performed on the UL in a group unit capable of transmitting the HARQ- Can be achieved. If there is not much transmission of the DL PDSCH on the unlicensed carrier, it is possible to transmit the HARQ-ACK only in the UL of the single LAA SCELL. The present invention can include both of these cases. When an HARQ-ACK transmission is performed on a UL-by-group basis, an unlicensed carrier capable of transmitting HARQ-ACKs depending on the channel availability based on channel access within a group, the LAA SCell index is dynamically changed on a subframe by subframe basis , Or it can be set semi-static to one unlicensed carrier, LAA SCELL. The base station receiving feedback on HARQ-ACK (s) based on the group can set CW_p and group_index to update and adapt to CW_p and group_index by managing CW_p and group_index for the DL PDSCH transmitted to the UE based on the group. group of the DL PDSCH (s) on the LAA Scell (s) set as the group.

(When HARQ-ACK for the PDSCH (s) transmitted on the DL on the unlicensed carrier is divided into UL on the licensed carrier and UL on the unlicensed carrier)

If the HARQ-ACK feedback for the PDSCHs transmitted on the unlicensed carrier, LAA Scell is divided into the UL on the licensed carrier, the PUCCH or the PUSCH on the unlicensed carrier, and the UL PUCCH or the PUSCH on the unlicensed carrier, The CW update and adaptation according to the ACK feedback is performed when the feedback which is regarded as a NACK is Z% or more based on Z% of the NACK (eg, 80 or 50, which may be a natural number value set by the base station) set it to doubling, otherwise set CW to reset. When the HARQ-ACK feedback is transmitted on the licensed carrier during the HARQ-ACK feedback for the PDSCHs transmitted to the LAA Cell, the CW for the LAA SCell for transmitting the PDSCH corresponding to the HARQ-ACK transmitted on the licensed carrier, A method of adjusting CWS as the corresponding combination for methods A-1, A-2, A-3, A-4 and B-1, B-2, B-3 as CW update and adaptation as described in the invention is used . Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

The CW update and adaptation according to the HARQ-ACK feedback transmitted on the unlicensed carrier on the UL is performed when the HARQ-ACK for the PDSCH (s) transmitted on the DL on the LAA Scell is transmitted on the unlicensed carrier, The CW update and adaptation for the PDSCH transmitted on the LAA SCell by applying the same method as that of the method 100 of the present invention by limiting the group to the LAA Scell that transmits the PDSCH corresponding to the HARQ- It can be used as a method. Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

Unlike the method of updating or adapting CW according to whether each cell transmitting HARQ-ACK independently is an unlicensed cell, LAA SCELL or licensed cell, HARQ-ACK feedback on a licensed carrier and HARQ-ACK feedback on an unlicensed carrier A method of managing the contention window for the LBT of the DL PDSCH transmission on the unlicensed carrier, LAA Scell, can also be considered. This is a hybrid method according to the method 100 and the method 110, and the conditions according to the methods 100 and 110, that is, the condition -100. When ACK detection is performed in the base station as a feedback value transmitted on the unlicensed carrier to the UL, the condition -110. If feedback considered as a NACK is not equal to or more than Z%, it is possible to set CW to be reset when both condition -100 and condition -110 are satisfied, and to set CW to doubling if both are not satisfied. Alternatively, considering that the condition 100 considers UL transmission on the unlicensed carrier, it may be considered that the channel condition of the unlicensed carrrier can be better reflected, and a method of resetting or doubling the CW according to whether the condition 100 is satisfied may be considered have. In contrast, the condition -110, which is designed to better reflect the channel state of all UEs, is considered to better reflect the channel status of unlicensed carriers in all UEs, and CW is reset according to whether condition -110 is satisfied a method of doubling may be considered. Also, the LBT to the CW_max value after the CW doubling of the base station is K = {1, ... , 8}, that is, when K times is repeatedly set, CWp is set to CW_min.

The present invention relates to a method for switching a UL LBT type performed by a UE when an UL channel access is performed.

The base station informs the terminal of parameters for the LBT type and LBT that the terminal should perform. The LBT type that the BS can inform the UE can be transmitted through the UL grant and inform the UL grant of the LBT type. For the LBT type to be informed, Cat-4 LBT, 25us LBT or No LBT can be indicated.

FIG. 27 is a diagram illustrating a method of switching an LBT type when a base station informs a terminal of an LBT type through an UL grant and a DL scheduling occurs between an UL grant transmission and a corresponding UL transmission, according to an embodiment of the present invention.

FIG. 27- (a) shows that a cat-4 LBT is performed through an UL grant for UL transmission in the 6th or 10th subframe from the first DL subframe. In this case, the UE can perform UL transmission by performing cat-4 LBT. Since the maximum channel occupancy time (MCOT) set from the first DL subframe is set to 3 ms in FIG. 27- (a), transmission to the UL set in the corresponding sixth or tenth subframe does not exist within the MCOT set by the DL In this case, the BS can instruct the MS to perform cat-4 LBT for UL transmission.

Alternatively, if UL is present in the MCOT set by the DL, for example, if the set MCOT from the first DL subframe is 8 ms, the base station sends an instruction to the terminal to perform 25us LBT through UL grant And the terminal receiving the indication can perform the 25us LBT and transmit the UL.

FIG. 27- (b) shows an example of the DL scheduling according to the DL scheduling need to be transmitted by the base station under the assumption that it instructs to perform cat-4 LBT through an UL grant for transmission on the UL set in the 6th or 10th subframe from the first DL subframe When the DL (the fifth subframe in FIG. 27- (b) is scheduled) prior to the transmission of the UL that has been scheduled, the UE that has detected the DL detects the LBT type by UL grant received from the first DL subframe A method that can be changed can be considered. In other words, when the base station has UL transmission within the MCOT set from the DL, it can be set to transmit UL through the 25us LBT, so that UL can be set to be transmitted through the 25us LBT instead of the instructed Cat-4 LBT. In this case, the BS sets triggering signaling to allow the MS to perform the 25us LBT, so that the MS receiving the signaling can transmit the UL by performing the LBT of 25us for its own UL transmission.

However, the problem here is that when the UL grant indicated by the base station is set to perform continuous multiple subframe scheduling through one grant as shown in FIG. 27- (a), (b) b), if the first DL subframe is set to perform the scheduling of the sixth and seventh UL subframes, a DL to be transmitted by the base station occurs in the middle and DL scheduling is performed in the fifth subframe, Is set to 2 ms, the UE that has been scheduled with the 6th and 7th consecutive multiple UL subframes from the first DL subframe is set to UL set for UL transmission in the 6th and 7th consecutive subframes, The LBT point of view is set within 2ms of newly formed DL MCs and can be modified from cat-4 LBT to 25us LBT. However, it can be applied to the 7th subframe set outside the 2ms MCOT LBT can benefit from the condition that the LBT point of the 6th subframe comes in the MCOT of 2ms even though the corresponding 7th subframe does not exist in the MCOT. Therefore, in terms of fairness between systems using other license- .

In order to improve this, a method of setting a cat-4 LBT to perform a seventh subframe transmission unintentionally from a base station, which has been scheduled to transmit a multiple subframe from the actual sixth subframe on the seventh subframe, is considered .

Alternatively, in the case where the sixth and seventh subframes are UL bursts and the length of the entire UL burst is not included in the MCOT newly formed by the DL, the LBT method according to the previously set UL grant, that is, In Fig. 27- (b), a method of performing cat-4 LBT set by the UL grant from the first DL subframe can be considered.

Although FIG. 27 illustrates the sixth UL burst, the sixth UL burst can be similarly applied to the tenth UL burst.

FIG. 28 is a diagram illustrating a method of switching an LBT type when a base station informs a terminal of an LBT type through an UL grant and DL scheduling occurs between an UL grant transmission and a corresponding UL transmission. FIG.

The UL in FIG. 28 indicates the LBT type for the UL burst in the scheduling of multiple subframes, and it is assumed that the UE performs the corresponding LBT.

In FIG. 28- (a), the BS schedules the 10th and 11th UL subframes from the first, second or third DL subframe, i.e., the UL grant on the preceding DL burst, and performs cat-4 LBT as a related LBT type, .

However, when DL scheduling (eighth subframe, ninth subframe) occurs between the UL grant transmission and the corresponding UL transmission as shown in FIG. 28- (b), when the MCOT of the DL burst is UL burst, subframe, the UL is present in the MCOT of the DL, so the LBT type for the 10th and 11th UL subframes is changed to perform the 25us LBT, and the UL is transmitted.

However, if the MCOT of the DL burst occurring between the UL grant transmission and the corresponding UL transmission does not include the UL burst, ie, the 10th and 11th UL subframes, as shown in FIG. 28- (c) 25us LBT only for the subframe and cat-4 LBT for the 11th subframe that does not.

In contrast, when the UL burst that is scheduled by multiple subframes is newly included in the MCOT formed by the DL as shown in FIG. 28- (d), the LBT type indicated by the UL grant from the BS And performs LBT of UL burst to transmit UL.

In Figure 28- (e), when DL scheduling (eighth subframe, 9th subframe) occurs between the UL grant transmission and the corresponding UL transmission, if the MCOT of the DL burst does not include a part of the UL burst An LBT of the UL burst is performed using the LBT type indicated by the UL grant from the base station, and the UL is transmitted.

FIG. 29 is a diagram illustrating a method of switching an LBT type when a base station informs a terminal of an LBT type through an UL grant and DL scheduling occurs between an UL grant transmission and a corresponding UL transmission. FIG.

The UL in FIG. 29 indicates the LBT type for each UL subframe constituting the UL burst in the scheduling of a multiple subframe or a single subframe, and it is assumed that the UE performs the corresponding LBT.

In FIG. 29- (a), the BS schedules the 10th and 11th UL subframes from the first, second or third DL subframe, i.e., the UL grant on the preceding DL burst, and assigns a cat- 4 LBT to transmit the UL.

As shown in Figure 29- (b), if the MCOT of the DL burst occurring between the UL grant transmission and the corresponding UL transmission does not include the UL burst, ie, the 10th and 11th UL subframes, the UL subframe Only 25us LBT is performed for the 11th subframe, and cat-4 LBT is performed for the 11th subframe that does not.

As shown in Fig. 29- (c), when the UL burst that is scheduled by multiple subframes does not include the entire UL burst within the MCOT formed by the DL, the LBT type indicated by the UL grant from the base station is used And performs UL burst LBT to transmit UL.

The implicit or explicit signaling method from the base station for swiching of the LBT type described with reference to FIG. 27 to FIG. 29 of the present invention can be considered, and the transmission of the corresponding UL burst through the detection of the first DL subframe on the UL burst, It is determined whether the DL is in the newly formed MCOT, and the LBT type for the UL transmission is changed to perform the LBT and transmit the UL. Alternatively, when the DL is scheduled between the UL grant transmission and the corresponding UL transmission, the base station transmits the signaling for changing the LBT type from the DL to the terminal, and the terminal changes the LBT type through the reception of the corresponding signaling So that the UL can be transmitted. Or the base station informs the terminal of the MCOT of each DL burst and if the UL burst is set to finish the UL burst within the MCOT set by the base station, the terminal changes the LBT type and performs the LBT through the 25us LBT UL can be transmitted.

In another embodiment of the switching of the UL LBT type illustrated in FIGS. 27 to 29, when the UL LBT type is switched, the transmission of the DL between the DL transmission performing the UL scheduling and the transmission of the scheduled UL is performed by the scheduling When a DL transmission is discontinuously transmitted, the LBT priority class for transmission of intervening DLs is signaled to the UE via the common-PDCCH, and the signaling LBT priority class and UL traffic or UL grant (or common PDCCH) to determine whether or not the UE switches the LBT type from the cat-4 LBT to the LBT with a single interval (eg, 25us LBT), and transmits the UL transmission To determine the LBT type.

In one embodiment, if transmission of a DL between a DL transmission that performs UL scheduling and a transmission of a scheduled UL is set such that the DL traffic is scheduled to be intermittently non-contiguous with a UL transmission that is scheduled for UL, In the DL transmission, signaling the LBT priority class for DL transmission intervening via the common-PDCCH, and the corresponding signaling and the terminal shall transmit the UL LBT priority class (the UL LBT priority class from the base station to the UL grant or common If the signaling is received via the PDCCH, the DL LBT priority class for the interfering DL transmission is compared with the UL LBT priority class received first (or the number of the LBT priority class is larger In the same case, if UL signaling is performed to perform cat-4 LBT as the LBT type, change it to perform LBT through 25us LBT, It is possible to send it. However, if the DL LBT priority class for interfering DL transmission is higher than the UL LBT priority class that is signaled first (or the number of LBT priority class is smaller), then cat-4 LBT as LBT type If the line signaling is performed to carry out the transmission, the cat-4 LBT is performed and the UL is transmitted without changing the signaling.

In another embodiment, when transmission of a DL between a DL transmission that performs UL scheduling and a transmission of a scheduled UL is set to be scheduled in the middle of the DL traffic discontinuously from a DL transmission that is scheduled for UL, In the DL transmission, signaling the LBT priority class for DL transmission intervening via the common-PDCCH, and the corresponding signaling and the terminal shall transmit the UL LBT priority class (the UL LBT priority class from the base station to the UL grant or common If the signaling is received through the PDCCH, the DL LBT priority class for the interfering DL transmission is higher than or equal to the UL LBT priority class signaling (or the number of the LBT priority class is smaller In case of UL-LBT type, if it receives line signaling to perform cat-4 LBT, change it to perform LBT through 25us LBT, It can be sent. However, if the DL LBT priority class for interfering DL transmissions is less than the UL LBT priority class received earlier (or the number of LBT priority classes is larger), then cat-4 LBT as the LBT type If the line signaling is performed to carry out the transmission, the cat-4 LBT is performed and the UL is transmitted without changing the signaling.

The present invention relates to a channel access method for transmitting multiple carriers in an uplink and a method for transmitting multiple carriers in accordance with channel access.

The following two methods are used as a method for accessing a channel on a multi-carrier in which a base station transmits on the LAA SCELL to the downlink. A Type A method of channel access for downlink multi-carrier transmission is a Type A method of channel access for downlink multi-carrier transmission, wherein each set of carriers, which is a combination of carriers for which the base station intends to perform transmission on the LAA SCell, 4 According to the method used in single carrier channel access using LBT, channel access for each carrier is followed, and according to the base station's judgment, the back-off counter is reduced in a specific carrier in order to align transmission time for transmission of multiple carriers A self-deferral time is set so as to set the transmission time point for multiple carriers. Similarly to the method used in Wi-Fi as a Type B method for downlink multi-carrier transmission, a carrier c_j is randomly selected from among carriers intended to be transmitted by the base station, or the carrier c_j ) To perform channel access using the cat-4 LBT in the corresponding carrier (c_j). When the channel access in the corresponding carrier is successful, the other carriers (c_i) immediately before the transmission time of the carrier, And performs channel sensing for at least T_mc = 25us at T_mc. If the signal is idle for T_mc, the base station performs transmission on multiple carriers including other carriers.

In a scheme in which a base station transmits multiple carriers in a downlink, carriers with intent to transmit the base station basically perform channel access by assuming a cat-4 LBT having a back-off. However, in the case of Type-B, only the cat-4 LBT is performed in the specific carrier defined by the base station, and the carriers carrying the cat-4 through the channel sensing of the 25us interval in the other carriers are subjected to channel- And if cat-4 in a specific carrier determined by the base station fails, transmission of multiple carriers is not possible regardless of the result of sensing in other carriers. However, in the case of an uplink in which the terminal performs transmission to the base station, the LBT type, i.e., Cat-4 LBT, or Cat-2 LBT that performs only sensing of a single interval (for example, 25us The LBT based only on the CCA) through the UL grant. Therefore, there may be a case where transmission on all carriers that perform transmission to the UE according to the LBT type indication of the base station through the UL grant is not always cat-4 LBT with back-off. That is, some of the carriers that the base station intends to transmit for the terminal to transmit may have one or multiple carriers indicating cat-4 LBT and one or multiple carriers indicating cat-2 LBT have. The present invention relates to a multi-carrier transmission method that can be transmitted in a terminal in the case, which will be described below.

FIG. 34 relates to the case where a base station intends to transmit on the LAA SCell on a multi-carrier from a mobile station to instruct each carrier to have a different UL LBT type by self-carrier scheduling of the UL grant (s).

First, when the Type-B scheme as a multi-carrier channel access scheme in the downlink is reused as an uplink multiple carrier access scheme, the number of carriers for instructing the UL cat- 4 LBT on the uplink, if the number of carriers instructed to perform the UL cat-4 LBT based on the UL grant received from the base station is multiple, It is necessary to select one of the carriers to be performed. This is because even in the Type-B scheme as a multi-carrier channel access scheme used in the downlink, the cat-4 DL LBT scheme is performed only on one carrier and the transmission is allowed only on the remaining carriers by Tmc . The following method can be used as a method for selecting one of the carriers that the UE should perform UL cat-4 LBT.

First, the UE selects one of the carriers to perform the UL cat-4 LBT through the signaling. In the case where the BS defines and designates one carrier to perform the UL cat-4 LBT, the BS can not perform channel access for transmission on the multiple carriers when the UE misses the corresponding UL grant. Therefore, the BS assigns a priority value of the carrier to the terminal in order to give priority to the cat-4 LBT, and signaling the terminal to the terminal. A method of signaling from the base station to the UE may be a method of instructing the UL grant to indicate the priority of the corresponding carrier. In other words, the UL grant (s) for performing the UL cat-4 LBT is signaled by including a priority value, so that the terminal can see the value indicated by the priority of the base station, 4 LBT, and if successful, only the Tmc is sensed for the remaining carriers, and the UL transmission on the multiple carriers is performed when the channel is idle. This is because even if the UL grant for the UL transmission in the carrier set to the highest priority is missed by the base station, the cat-4 LBT for UL transmission can be performed according to the next higher priority value. Lt; / RTI &gt;

One of the following methods may be used to select one of the carriers to be subjected to the UL cat-4 LBT according to a pre-defined rule between the BS and the MS.

1) Select the carrier having the lowest index among the carriers indicated by UL Cat-4 LBT. That is, the terminal selects cat-4 LBT as a carrier to perform UL cat-4 LBT among the carriers receiving the UL grant with UL Cat-4 LBT and performs at least Tmc for the remaining carriers And transmits it when it is idle. This can be a robust method when the UL grant is missed by selecting a carrier based on the received UL grant of the UE.

2) Select the carrier with the largest contention window size (CWS) among the carriers directed to UL Cat-4 LBT. That is, the UE selects the carrier having the largest CWS among the carriers receiving the UL grant with the UL Cat-4 LBT as a carrier to be subjected to the UL cat-4 LBT and performs the cat-4 LBT and performs at least Tmc is detected and transmitted in the case of idle. This is a method for maximally ensuring coexistence with Wi-Fi, and may be a robust method in case of missing a UL grant by selecting a carrier based on a received UL grant of the terminal.

3) Select the carrier with the smallest contention window size (CWS) among the carriers directed to UL Cat-4 LBT. That is, the UE selects the carrier having the smallest CWS among the carriers receiving the UL grant with the UL Cat-4 LBT as a carrier to be subjected to the UL cat-4 LBT and performs cat-4 LBT and performs at least Tmc is detected and transmitted in the case of idle. This is a method for maximizing the transmission of the LAA which performs schedule access based on the schedule grant, unlike Wi-Fi, which allows coexistence with Wi-Fi. This is because if a UL grant is missed by selecting a carrier based on the received UL grant It can be a robust way to.

4) Let the random back-off counter among the carriers pointed to the UL Cat-4 LBT select the largest back-off counter carrier. That is, the UE selects the carrier having the largest random back-off counter among the carriers receiving the UL grant with the UL Cat-4 LBT as a carrier to be subjected to the UL cat-4 LBT and performs the cat-4 LBT, For example, at least Tmc is sensed, and if it is idle, transmission is performed. This is a method for maximally ensuring coexistence with Wi-Fi, and may be a robust method in case of missing a UL grant by selecting a carrier based on a received UL grant of the terminal.

5) Let the random back-off counter of the carriers pointed to UL Cat-4 LBT select the smallest back-off counter carrier. That is, the UE selects the carrier having the smallest random back-off counter among the carriers receiving the UL grant with the UL Cat-4 LBT as the carrier to be subjected to the UL cat-4 LBT and performs the cat-4 LBT, For example, at least Tmc is sensed, and if it is idle, transmission is performed. . This is a method for maximizing the transmission of the LAA which performs schedule access based on the schedule grant, unlike Wi-Fi, which allows coexistence with Wi-Fi. This is because if a UL grant is missed by selecting a carrier based on the received UL grant It can be a robust way to.

FIG. 35 illustrates a case where a base station intends to transmit on the LAA SCell on a multi-carrier from the terminal to instruct each carrier to have a different UL LBT type by self-carrier scheduling of the UL grant (s) And an uplink multi-carrier transmission operation in case of LBT failure in LBT carrier (s).

If the UL LBT in the carriers performing the UL cat-2 LBT succeeds even if the UL LBT fails in the carrier (s) performing UL cat-4 LBT in FIG. 35, the corresponding UL cat- To perform multi-carrier transmission of only the carriers to be performed. In the case of downlink, if cat-4 in a specific carrier determined by the base station fails in channel access of multiple carriers such as Type-B, LBT is not performed in other carriers, Regardless of the result of the sensing, transmission to multiple carriers that do not include a carrier carrying cat-4 LBT is impossible. However, in the case of the uplink, the UL grant (s) transmitted from the base station is set to indicate the UL LBT type for each carrier, and the LBT in the carrier performing cat- LBT failure may occur according to the corresponding interference condition or channel state. However, when the UL cat-2 LBT is instructed to perform the indicated UL cat-2 LBT according to the intention from the base station, It is possible to allow channel access on the corresponding multiple carriers and to perform transmission on the uplink multiple carriers. FIG. 35 exemplifies a case of receiving UL scheduling of a single subframe as an embodiment, but the same can be applied to the case of scheduling multiple subframes through one UL grant as shown in FIG. 36, Likewise, the present invention can be applied to the case of scheduling multiple subframes through UL grants transmitted from different downlink subframes and performing uplink transmission. In addition, as shown in FIG. 38, each UL scheduled subframe of the UL transmission burst includes one (S) in the DL subframe.

36 shows a case in which a base station performs transmission on an LAA SCell on a multi-carrier from a mobile station and instructs each carrier to have a different UL LBT type for multiple subframes by self-carrier scheduling of an UL grant (s) .

FIG. 37 shows a case where a base station performs self-carrier scheduling of an UL grant (s) by intending to transmit on a LAA SCell on a multi-carrier from a mobile station, and performs multiple subframe scheduling. For each subframe of multiple subframes, the UL grant (s) is transmitted from the subframe to indicate the UL LBT type which may be the same or different in each carrier and in different UL subframes.

According to FIG. 37, the number of multiple carriers that can be transmitted according to the UL transmission time and the success of the LBT performed before the transmission time of each subframe may be changed for each subframe, and UL cat-4 LBT In the case where the UL cat-4 LBT is performed in the subframe of the carrier, when the channel access type of the multiple carriers set to be executable to the UE is signaled in Type-B, the UL cat- UL LBT can perform UL transmission in multiple carriers by performing Tmc sensing at a time immediately before LBT completion of the carrier in which Tmc = 25us sensing, i.e., UL cat-4 LBT is performed.

FIG. 38 shows a case where a base station performs self-carrier scheduling of an UL grant (s) by intending to transmit on the LAA SCell on a multi-carrier from a mobile station, and performs multiple subframe scheduling. For each subframe of a multiple subframe, (S) from a different UL subframe or from a different DL subframe to indicate UL LBT types that may be the same or different in each carrier and in different UL subframes.

38, the number of multiple carriers that can be transmitted according to the UL transmission timing and the success of the LBT performed before each subframe transmission time is the same as that described in FIG. 37 except for the scheduling method with multiple subframes, When UL CAC-4 LBT is performed in a subframe of a carrier configured to perform UL cat-4 LBT, when a channel access type of a multi-carrier set to be executable to a UE is signaled in Type-B, UL The UL LBT in a carrier other than the cat-4 LBT carrier performs Tmc sensing just before the LBT finish of the carrier in which the UL cat-4 LBT is performed, UL transmission can be performed.

This is because, in the case where the UE performs transmission to the UL, transmission in the uplink is performed in units of subframes even if the scheduling indicated in the UL grant is a scheduling of a single subframe or a scheduling of multiple subframes, To enable UL transmission to carriers capable of transmission at the time of transmission.

Although UL transmission in each carrier has shown FIGS. 35 to 38 as an example of a diagram for self-carrier transmission, it is also possible to designate UL cat-4 LBT / UL cat-2 LBT as another embodiment of the present invention The UL grant may be cross-carrier scheduling from the PCell or SCell using the licensed band, or cross-carrier scheduling from the LAA SCell using the license-exempt band. The cat-4 LBT can be directed via cross-carrier scheduling. The scheduling method for UL transmission in each carrier can be self-carrier scheduling or cross-carrier scheduling. Therefore, even if two scheduling methods are applied differently for each carrier, Accordingly, the application of the channel access method over multiple carriers can be equally applied according to the method proposed by the present invention.

In another embodiment of the present invention, LBT gaps for performing LBT are not specified and are not described between consecutive UL subframes in the drawings of FIGS. 36 to 38. However, in the case where a gap exists, Can be applied.

The present invention relates to an uplink CWS adaptation method in a base station and a mobile station for PUSCH transmission when transmitting a PUSCH scheduled on a multicarrier in an uplink. When scheduling PUSCH transmission by a base station, UL-cat-4 LBT or UL cat-2 LBT as the LBT type to be performed by the terminal, unlike in the downlink for performing the cat-4 LBT, , LBT that performs CCA for 25us duration) through the UL grant, and the receiving terminal transmits the PUSCH by performing the LBT according to the designated LBT type. Therefore, a scheme different from the CWS adaptation scheme in the channel access scheme used for multi-carrier transmission in the downlink assuming only the cat-4 LBT is needed.

The following two methods are used as a method for accessing a channel on a multi-carrier where a base station transmits on the LAA SCell to the downlink.

A Type A method of channel access for downlink multi-carrier transmission is a Type A method of channel access for downlink multi-carrier transmission, wherein each set of carriers, which is a combination of carriers for which the base station intends to perform transmission on the LAA SCell, 4 In order to match the transmission time point for the transmission of multiple carriers according to the judgment of the base station, the back-off (BO) is performed in a specific carrier according to the method used in the single carrier channel access using the LBT, the self-deferral time is set so as not to reduce the counter so that the transmission time point for the multiple carriers is matched. There are two methods of CWS adaptation in the Type A method for downlink multicarrier transmission. The first method is to manage the CWS in each carrier according to the method used in Type A1, single carrier channel access, and to extract the BO counter independently for each carrier. The second scheme manages CWS in each carrier according to the method used in Type A2, single carrier channel access, but sets a common BO counter for multi-carrier transmission, which selects the largest CWS (largest CWS) among the CWS of each carrier And setting the selected BO counter in the CWS to the common BO counter.

As a Type B method for downlink multi-carrier transmission, similar to the method used in Wi-Fi, a carrier (c_j) is randomly selected from among carriers intended to be transmitted by the base station, or the carrier (c_j) To perform channel access using the cat-4 LBT in the corresponding carrier (c_j), and when the channel access in the corresponding carrier is successful, the channel access is performed on the other carriers (c_i) The BS performs channel sensing for at least T_mc = 25us, and if the channel is idle for T_mc, the base station performs transmission on multiple carriers including other carriers c_i. Also, there are two methods of CWS adaptation in the Type B method for downlink multicarrier transmission. The first scheme is to have a single CW in Type B1, a set of carriers for multicarrier transmission (set C), and a method for managing one CWS, in a reference subframe transmitted from all carriers in set C If the HARQ-ACK values considered as NACK based on the HARQ-ACK feedback corresponding to the PDSCH transmission are at least 80% or more, the CW is increased. Otherwise, the CW is reset to the minimum value. The second scheme is to set the BO counter for the carrier (c_j) that performs CWS for each carrier but performs cat-4 for multiple carrier Type B transmissions in the manner used in Type B2, i.e., single carrier channel access, The largest CWS (the largest CWP) among the CWS of the CWS is selected and set to the BO counter selected in the CWS.

As described in the present invention, in a scheme in which a base station transmits multiple carriers in a downlink, carriers with intent to transmit by the base station basically perform channel access by assuming a cat-4 LBT having a back-off. However, in the case of Type-B, only the cat-4 LBT is performed in the specific carrier defined by the base station, and the carriers carrying the cat-4 through the channel sensing of the 25us interval in the other carriers are subjected to channel- And if cat-4 in a specific carrier determined by the base station fails, transmission of multiple carriers is not possible regardless of the result of sensing in other carriers. However, in the case of an uplink in which the terminal performs transmission to the base station, the LBT type, i.e., Cat-4 LBT, or Cat-2 LBT that performs only sensing of a single interval (for example, 25us The LBT based only on the CCA) through the UL grant. Therefore, there may be a case where transmission on all carriers that perform transmission to the UE according to the LBT type indication of the base station through the UL grant is not always cat-4 LBT with back-off. That is, some of the carriers that the BS intends to transmit to perform the transmission at a particular transmission time may have one or multiple carriers indicating the cat-4 LBT, and one or multiple There may be carriers. The present invention relates to a CWS adaptation method in case of multi-carrier transmission in a terminal in the case, which will be described below.

Unlike the downlink multi-carrier transmission method, in an uplink transmission in each carrier in which a UE performs transmission, the corresponding sub-carrier is dynamically UL transmitted by a base station to a subframe level or a multiple subframe level, UL cat-4 LBT or UL cat-2 LBT for UL can be designated, so that the UE can set up to manage CWS for each carrier as an uplink multi-carrier transmission method. The terminal shall manage the CWS for each carrier regardless of whether it is UL cat-4 LBT or UL cat-2 LBT for PUSCH transmission on each carrier as the LBT type indicated by the UL grant by the base station for each carrier Therefore, when the base station requests simultaneous transmission of multiple carriers to the mobile station, or when it is necessary to transmit multiple carriers in the mobile station, the mobile station transmits the PUSCH on the multiple carriers until the simultaneous transmission can start within the interval allowing the LBT It can be set to have a self-deferral time according to the needs of each carrier.

As an example of setting up a carrier capable of having a self-deferral time, the LBT type in all carriers intended for multi-carrier transmission has a self-deferral time regardless of whether it is cat-2 LBT or cat-4 LBT There may be a way to enable multi-carrier transmission. As an example, if the channel sensing on the carrier performing cat-4 LBT ends after the channel sensing period on the carrier performing cat-2 LBT, the self-deferral time Lt; RTI ID = 0.0 &gt; a &lt; / RTI &gt; multiple carrier transmission.

As another embodiment, it is possible to set the self-deferral time only in the carriers indicated by cat-4 LBT, but it is possible to transmit on all carriers at the time of transmission regardless of the setting of cat-2 LBT / cat-4 LBT There may be a method for allowing transmission of multiple carriers. Since the UL LBT section on the carrier instructed to perform UL Cat-2 LBT is stochastically shorter than the LBT section on the carrier instructed to perform the UL cat-4 LBT, only the carriers designated cat- deferral time can be set so as to perform multi-carrier transmission.

As another embodiment, there may be a method of setting the self-deferral time only in the carriers indicated by the cat-4 LBT so as to perform transmission of multiple carriers composed only of carriers performing cat-4. This is because the UL LBT interval on the carrier instructed to perform the UL Cat-2 LBT is stochastically shorter than the LBT interval on the carrier instructed to perform the UL cat-4 LBT, -deferral time can be set so that multi-carrier transmission is possible, and when at least one carrier of the carriers performing cat-4 is busy, the cat-2 LBT is transmitted at the time of transmission of the indicated carrier This is a way to make it possible.

In addition, as a method for adjusting the CWS for performing the cat-4 LBT in the case of downlink in the uplink CWS adaptation in transmission to the downlink multi-carrier, the CWS (BO) counter from the CWS of the carrier with the largest CWS in the set of CWS of the carrier to apply the corresponding BO counter to all carriers that intend to transmit multiple carriers. However, unlike the CWS adaptation setup, which assumes the cat-4 LBT in the downlink at all times, the cat-2 LBT or the cat-4 LBT in the uplink carrier can be performed. A method of setting CWS adaptation in uplink multi-carrier transmission according to received carriers can be further considered.

In the first case, when a method such as Type-A2 in the case of downlink multi-carrier transmission is applied to the uplink, an individual managed CWS in a carrier scheduled to perform UL cat-2 LBT ambiguity arises whether to include it as a carrier set to select the largest CWS. To solve this problem, the present invention explains the following two methods. The first method is to select the largest CWS among the CWS of all scheduled carriers for UL transmission on multiple carriers, and to set the CWS to extract the common BO counter N. This is because the indication of cat-4 LBT / cat-2 LBT for each carrier is dynamically set through UL grant and is configured to manage CWS for each carrier, so that UL cat-2 LBT It is possible to extract a common back-off counter in consideration of the CWS in all carriers that are intended to transmit UL multi-carrier. The second method is to select the largest CWS among the CWS of the carriers that are instructed to perform the cat-4 LBT among the scheduled carriers for UL transmission on the multiple carriers, and to extract the common BO counter N therefrom . This is due to the fact that only CWSs for UL transmissions in the carriers that are responsible for performing the UL cat-4 LBT at the current time, even though they manage the CWS in each carrier, If the CWS for the UL transmission being managed is larger than the CWS for the UL transmission in the carriers that perform the cat-4 LBT, the possibility of unnecessarily adding back-off is excluded, and the method requires uplink multi-carrier transmission There is an advantage in terms of increasing the likelihood of acquiring the channel at the time.

As another embodiment, when a method such as Type-B2 in the case of downlink multi-carrier transmission is applied to the uplink, the individual managed CWS in the carrier scheduled to perform the UL cat-2 LBT is referred to as the largest Ambiguity arises whether to include CWS as a carrier set to select. To solve this problem, the present invention explains the following two methods. The first method is to select the largest CWS among the CWS of all scheduled carriers for UL transmission on multiple carriers and to set the BO counter N of the representative carrier to perform UL cat-4 LBT to be extracted here to be. This is because the indication of cat-4 LBT / cat-2 LBT for each carrier is dynamically set through UL grant and is configured to manage CWS for each carrier, so that UL cat-2 LBT 4 LBT is performed considering the CWS of all carriers that are intended to transmit UL multi-carrier even if the CWS is received. The second method is to select the largest CWS among the CWS of the carriers that are scheduled to perform the cat-4 LBT among the scheduled carriers for UL transmission on the multiple carriers, and then transmit the UL cat-4 LBT to the representative carrier To extract the BO counter N of the received packet. This is due to the fact that only CWSs for UL transmissions in the carriers that are responsible for performing the UL cat-4 LBT at the current time, even though they manage the CWS in each carrier, If the CWS for the UL transmission being managed is larger than the CWS for the UL transmission in the carriers that perform the cat-4 LBT, the possibility of unnecessarily adding back-off is excluded, and the method requires uplink multi-carrier transmission There is an advantage in terms of increasing the likelihood of acquiring the channel at the time.

In the case of applying the Type B scheme used in the downlink in the uplink multi-carrier transmission, that is, cat-4 LBT is applied only to the representative carrier, and the channel access 4 terminal LBT or UL cat-2 LBT signal through the UL grant, the terminal immediately receives the T_mc, that is, the channel sensing only through the 25us CCA, just before the carrier of the representative carrier successfully accesses the channel It is necessary to solve the problem of CWS adaptation for UL transmission signaling UL cat-4 LBT or UL cat-2 LBT transmitted to the corresponding carrier in the next CWS determination for UL transmission.

In one method, when the UE performs uplink multi-carrier transmission, regardless of whether the UE has received an LBT type signaling or a LBT type from the base station in a specific carrier, It is possible to determine ACK, NACK, or DTX based on detection at the base station for UL transmission in the carrier, and apply the CWS adjustment. In case of managing one CWS for multiple carriers, it is possible to perform CWS adjustment by determining ACK, NACK or DTX for transmission in a reference subframe for all carriers that have performed UL transmission with multiple carriers.

Another method is to determine ACK, NACK or DTX based on detection at the base station for UL transmission in the carrier only for UL transmission in each carrier that has received UL cat-4 LBT signaling with LBT type, It can be applied to adjustment. This is because it is set to expect adjustment of the CWS of the terminal in the carrier set by the base station to perform cat-4 LBT. Therefore, the terminal performs channel sensing only for Tmc = 25us by actually transmitting the LBT type by Type-B It is possible to perform CWS adjustment even if it participates in multi-carrier transmission, and to perform CWS adjustment according to the determination of ACK, NACK or DTX in the transmission in the reference subframe for the carrier.

Alternatively, the UE transmits an UL cat-4 LBT signaling to the UL-4 LBT signaling and performs cat-4 LBT transmission only for the UL transmission in each carrier. For UL transmission on the carrier, NACK or DTX is determined and applied to the CWS adjustment. Considering that the carrier performing cat-2 for the transmission of a single carrier does not consider the corresponding carrier for the CWS adjustment, compared to the terminal transmitting the LAA UL in which the transmission of multiple carriers is not set, It may be difficult to obtain a channel for transmission of multiple carriers. Therefore, even if the UE has participated in multi-carrier transmission, it can be configured not to perform CWS adjustment for UL transmission to a carrier that does not actually perform cat-4.

The present invention relates to a terminal operation after LBT failure of a preceding subframe when multiple subframe scheduling is performed in transmission on a single carrier.

- Multiple subframes If there are LBT gaps or CCA gaps for performing LBT between consecutive subframes that are scheduled,

  4 UL-cat-4 LBT based on LBT type received from UL grant for multiple subframe or UL cat-4 LBT based on specified LBT type from UL grant for each subframe at multiple subframe If the LBT of the preceding subframe fails, a new BO counter for transmission to the next UL subframe is set to be extracted, and the UE is set to follow the UL channel access procedure.

  4 UL-cat-4 LBT based on LBT type received from UL grant for multiple subframe or UL cat-4 LBT based on specified LBT type from UL grant for each subframe at multiple subframe , If the LBT of the preceding subframe fails, sets the preceding BO counter to resume and sets it to follow the UL channel access procedure.

- Multiple subframes If there is no LBT gap or CCA gap to perform LBT between consecutive subframes that are scheduled,

  4 UL-cat-4 LBT based on LBT type received from UL grant for multiple subframe or UL cat-4 LBT based on specified LBT type from UL grant for each subframe at multiple subframe , The BO counter is set to resume the BO counter after the LBT failure of the preceding subframe for transmission of the next subframe, and is set to follow the UL channel access procedure.

The present invention relates to a terminal operation after LBT failure of a preceding subframe in a specific carrier when performing multiple subframe scheduling in transmission in multiple carriers.

If multi-subframe scheduling is scheduled for at least one carrier with no gap, it may not always be possible to transmit on other carriers that have failed in a particular LBT due to continuous transmission of carriers set to no gap. In order to solve this problem, when a UE is scheduled for multiple carriers and has a no gap for a specific carrier, a UE has a gap of no gap, and among the subframes in a carrier subjected to multiple subframe scheduling, A method can be considered in which multiple carrier transmission can be performed simultaneously with carriers that are currently LBT succeeded in transmission in the other carrier in which the preceding LBT failed.

While the methods and systems of the present invention have been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (1)

Method, apparatus and system for uplink channel access for license - exempt band communication.

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