KR20180137355A - Method, apparatus, and system for transmitting downlink control signal in wireless communication system - Google Patents

Abstract

The present invention relates to a method for efficiently transmitting a preemption indicator to indicate information whether downlink resources are preempted and related preemption information when the preemption of downlink resources already used in a mobile communication system occurs. More specifically, a terminal determines a CORESET for monitoring a preemption indicator according to PDSCH allocation of the terminal and performed blind decoding the preemption indicator in the corresponding CORESET.

Description

Technical Field [0001] The present invention relates to a method, apparatus, and system for transmitting downlink control information in a wireless communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a terminal apparatus for transmitting a preemption indicator in a wireless communication system.

3GPP LTE (-A) defines uplink / downlink physical channels for physical layer signal transmission. For example, a physical uplink shared channel (PUSCH) which is a physical channel for transmitting data in the uplink, a physical uplink control channel (PUCCH) for transmitting a control signal, and a physical random access channel (PRACH) A physical downlink shared channel (PDSCH) for transmitting data in downlink, a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), a physical hybrid ARQ indicator channel (PHICH) ).

A downlink control channel (PDCCH / EPDCCH) of the channels is a channel for transmitting uplink / downlink scheduling assignment control information, uplink transmission power control information, and other control information to one or a plurality of terminals. Since there is a limitation on the resources available for the PDCCH that can be transmitted at one time, it is not possible to allocate different resources to each terminal, and the control information should be transmitted to any terminal by sharing resources. For example, in 3GPP LTE (-A), four Resource Elements (REs) are grouped together to form REGs (Resource Element Groups), nine CCEs (Control Channel Elements), and one or a plurality of CCEs And informs the UE of a resource, and a plurality of UEs can share the CCE. Here, the number of CCEs to be combined is called CCE coupling level, and the resource to which CCE is allocated according to the possible CCE coupling level is called a search space. The search space may include a common search space defined for each base station and a terminal-specific or UE-specific search space defined for each terminal. The UE performs decoding on the number of possible CCE combining cases in the search space and can determine whether it corresponds to its own PDCCH through the UE identifier included in the PDCCH. Therefore, it takes a long time to decode the PDCCH and energy consumption is inevitable.

Efforts are underway to develop an improved 5G or pre-5G communication system to meet the growing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G network) communication system or after a LTE system (Post LTE). To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In order to mitigate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave, in the 5G communication system, beamforming, massive MIMO, full-dimension MIMO (FD-MIMO ), Array antennas, analog beam-forming, and large scale antenna technologies are being discussed. In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Have been developed. In addition, in the 5G system, the Advanced Coding Modulation (ACM) scheme, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), the advanced connection technology, Filter Bank Multi Carrier (FBMC) (non-orthogonal multiple access), and SCMA (sparse code multiple access).

On the other hand, the Internet is evolving into an Internet of Things (IoT) network in which information is exchanged between distributed components such as objects in a human-centered connection network where humans generate and consume information. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired / wireless communication, network infrastructure, service interface technology and security technology are required. In recent years, sensor network, machine to machine , M2M), and MTC (Machine Type Communication). In the IoT environment, an intelligent IT (Internet Technology) service can be provided that collects and analyzes data generated from connected objects to create new value in human life. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, and advanced medical service through fusion of existing information technology . ≪ / RTI >

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as a sensor network, a machine to machine (M2M), and a machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antennas It is. The application of the cloud RAN as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

Generally, a mobile communication system has been developed to provide voice service while ensuring the activity of a terminal. However, the mobile communication system is gradually expanding not only to voice but also to data service, and now it has developed to the extent of providing high-speed data service. However, in a mobile communication system in which services are currently provided, a lack of resources and terminals require higher-speed services, and therefore, a more advanced mobile communication system is required.

As mentioned above, the 3GPP NR (New Radio) system is a 5G candidate system for supporting various future service scenarios. 3GPP NR (New Radio) can provide services such as Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communication (URLLC) and Enhanced Machine-type communication (eMTC) to users with bandwidths up to 400 MHz.

The 3GPP NR system defines uplink / downlink physical channels for physical layer signal transmission. For example, a physical uplink shared channel (PUSCH) which is a physical channel for transmitting data in the uplink, a physical uplink control channel (PUCCH) for transmitting a control signal, and a physical random access channel (PRACH) A physical downlink shared channel (PDSCH) for transmitting data in the downlink, and a physical downlink control channel (PDCCH) for transmitting an L1 / L2 control signal. A downlink control channel (PDCCH) among the channels is a channel for transmitting uplink / downlink scheduling assignment control information, uplink transmission power control information, and other control information to one or a plurality of terminals. In order that one or a plurality of UEs can easily receive a downlink control channel (PDCCH), the PDCCH may be located in the first part OFDM symbol of one slot as a time domain resource and may be located in some resource in the frequency domain. A resource monitored by the UE in order to receive the PDCCH may be referred to as a control resource set (CORESET). The CORESET may assign one or more CORESET to one UE.

 In the structure of the PDCCH located in the CORESET in the 3GPP NR system, one CCE (Control Channel Element) is formed by grouping six REGs (Resource Element Groups) composed of one OFDM symbol and one PRB (Physical Resource Block) One or a plurality of CCEs are combined and transmitted. Here, the number of CCEs combined is referred to as a CCE aggregation level, and a resource to which a PDCCH is allocated according to a possible CCE coupling level is referred to as a search space. The search space may include a common search space defined for each base station and a terminal-specific or UE-specific search space defined for each terminal. The UE performs blind decoding on the number of possible CCE combining cases in the search space and can determine whether it corresponds to its own PDCCH through a user equipment (UE) identifier included in the PDCCH.

Generally, the amount of the PDCCH that needs to be transmitted may vary with time depending on the traffic environment of the user and the channel condition. If the size of the time-frequency resource of the CORESET to which the PDCCH can be transmitted is fixed, a plurality of PDCCHs can not be simultaneously allocated in the network, or a time-frequency resource of CORESET can be wasted by allocating only a small number of PDCCHs. Therefore, in order to use the CORESET time-frequency resources effectively, the size of the CORESET time-frequency resource can be changed according to the traffic environment and the channel conditions of the user and can be varied with time.

As mentioned earlier, future 5G technologies require lower latency data transmission due to the emergence of new applications such as real-time control and tactile internet, The delay is expected to be reduced to 1ms. 5G aims to provide a data delay that is about 10 times lower than the conventional one. To solve this problem, 5G is expected to propose a communication system using a mini-slot having a shorter TTI period (e.g., 0.2ms) in addition to the existing slot (or subframe).

In mobile communication, a base station simultaneously uses a slot and a mini-slot to simultaneously support terminals having various requirements. In particular, it is expected to use slot / mini-slot multiplexing method to puncture a resource to be used as a slot to provide a low-delay service and to transmit a mini-slot. In a slot-based terminal, puncturing causes not only the information of one or more CBs (code blocks) of the slot to be transmitted, but also the performance of other terminals is transmitted to the corresponding CBs.

In the 3GPP NR system, when a time / frequency resource already allocated to a terminal as a downlink resource and a part of a time / frequency resource already allocated to the terminal are reassigned to the same or another terminal and used, This section describes how to send a preemption indicator to tell When the UE is configured to monitor CORESETs of a plurality of bandwidth parts, the UE always monitors all the CORESETs, which may cause a problem in terms of energy consumption of the UE. Therefore, instead of monitoring all CORESETs, some CORESET monitoring is required depending on the preemption possibilities.

The objects that can be achieved by the present invention are not limited to those specifically described herein.

In order to solve the above technical problem, the technical aspect of the present invention is that when a base station configures a plurality of bandwidth parts to a terminal, the base station constructs a CORESET corresponding to each bandwidth part, and a corresponding time of a bandwidth part corresponding to each CORESET / A preemption indicator transmission method of a base station transmitting information on a preemption occurred in a frequency domain.

SUMMARY OF THE INVENTION In order to solve the above technical problems, a technical aspect of the present invention is that when a terminal has a plurality of bandwidth parts configured from a base station, the terminal monitors a CORESET corresponding to each bandwidth part, To a preemption indicator reception method of a terminal and a CORESET monitoring method of a terminal for monitoring information about a preemption occurring in a corresponding time / frequency domain of the terminal.

SUMMARY OF THE INVENTION In order to solve the above technical problem, a technical aspect of the present invention is to provide a method and apparatus for transmitting a preamble generated in a corresponding time / frequency domain of a Bandwidth part to a CORESET (s) corresponding to a Bandwidth part To a preemption indicator transmission method of a base station transmitting the preemption indicator.

SUMMARY OF THE INVENTION In order to solve the above technical problem, a technical aspect of the present invention is to provide a preemption that occurs in a corresponding time / frequency domain of a bandwidth part in a CORESET (s) corresponding to a bandwidth part (s) allocated to a PDSCH from a base station To a method for receiving a preemption indicator of a terminal and a method for monitoring a CORESET of the terminal.

In order to solve the above technical problem, a technical aspect of the present invention is to provide a preemption that occurs in a corresponding time / frequency domain of a bandwidth part in a CORESET (s) commanded by a base station irrespective of a bandwidth part (s) To a method for receiving a preemption indicator of a terminal and a method for monitoring a CORESET of the terminal.

It will be understood by those skilled in the art that various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the following detailed description of the invention, do.

According to the embodiment of the present invention, since the terminal can perform blind decoding in the terminal by limiting the CORESET to which the preemption indicator is likely to be transmitted, the number of blind decodings can be reduced, thereby reducing energy consumption of the terminal .

1 shows an example of a radio frame structure used in a wireless communication system.
2 shows an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system.
3 is a view for explaining a physical channel used in a 3GPP system and a general signal transmission method using the same.
FIG. 4 illustrates a radio frame structure for transmission of a synchronization signal (SS).
5 is a diagram illustrating a structure of a downlink radio frame used in an LTE system.
6 illustrates a configuration of a cell specific common reference signal.
FIG. 7 shows an example of a UL subframe structure used in a wireless communication system.
8 is a conceptual diagram illustrating a carrier aggregation (CA) technique.
FIG. 9 is a diagram for explaining Single Carrier Communication and Multiple Carrier Communication. FIG.
10 is a diagram showing an example in which a cross carrier scheduling technique is applied.
11 is a diagram illustrating a deployment scenario of a UE and a BS in an LTE and LAA service environment.
12 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention.
13 is a diagram of a control region of a PDCCH for control channel transmission in LTE (-A).
Fig. 14- (a) is a diagram of a procedure for transmitting control information in LTE (-A).
FIG. 14- (b) is a diagram for CCE aggregation of PDCCH and multiplexing of PDCCH in LTE (-A).
FIG. 15 is a diagram showing a search space allocation by CCE aggregation for a common search space in the LTE (-A) and a UE specific (or terminal specific) search space.
16 is a diagram showing a CORESET to which a PDCCH in a 3GPP NR system can be transmitted.
17 is a diagram relating to a bandwidth part.
18 is a diagram showing a bandwidth part and CORESET corresponding thereto.
FIG. 19 is a diagram illustrating a bandwidth part and corresponding CORESET and preemption indicator. FIG.
FIG. 20 is a diagram illustrating a preemption indicator according to allocation of a PDSCH when bandwidth parts are configured not to overlap. FIG.
FIG. 21 is a diagram illustrating a preemption indicator according to allocation of a PDSCH when bandwidth parts are configured to overlap. FIG.
22 is a diagram illustrating a preemption indicator transmitted on a specific-terminal PDCCH according to allocation of a PDSCH when bandwidth parts are configured not to overlap.
FIG. 23 is a diagram illustrating a preemption indicator transmitted on a specific-terminal PDCCH according to allocation of a PDSCH when bandwidth parts are configured to overlap. FIG.
24 is a diagram illustrating transmission and reception of a preemption indicator in a CORESET to which a PDCCH for scheduling a PDSCH is transmitted.

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 "

FIG. 1 shows an example of a radio frame structure used in a wireless communication system.

Particularly, FIG. 1 (a) shows a frame structure for a frequency division duplex (FDD) used in a 3GPP LTE / LTE-A system and FIG. 1 Time division duplex (TDD) frame structure.

Referring to FIG. 1, a radio frame used in the 3GPP LTE / LTE-A system has a length of 10 ms (307200 Ts) and is composed 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.

[Table 1]

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.

[Table 2]

2 illustrates an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, Figure 2 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. 2, a slot includes a plurality of OFDM symbols in a time domain and a plurality of resource blocks (RB) in a frequency domain. The OFDM symbol also means one symbol period. Referring to FIG. 2, 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. 2 illustrates a subframe in which one slot is composed of seven OFDM symbols for convenience of description, embodiments of the present invention may be applied to subframes having a different number of OFDM symbols in a similar manner. Referring to FIG. 2, 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.

3 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 a base station when power is increased or newly enters a 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. 4 illustrates a radio frame structure for transmission of a synchronization signal (SS). In particular, FIG. 4 illustrates a radio frame structure for transmission of a synchronous signal and a PBCH in a frequency division duplex (FDD). FIG. 4A illustrates a radio frame in a normal CP (normal cyclic prefix) SS and PBCH. FIG. 4 (b) shows transmission positions of SS and PBCH in a radio frame configured with 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. 4, 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. 4, 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. 4, 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.

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

Referring to FIG. 5, 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 ".

FIG. 6 illustrates the configuration of a cell specific common reference signal. In particular, Figure 6 illustrates a CRS structure for a 3GPP LTE system supporting up to four antennas.

[Equation 1]

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

&Quot; (2) "

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

&Quot; (3) "

Referring to FIG. 6 and Equations 1 and 2, the current 3GPP LTE / LTE-A standard defines a cell-specific CRS used for demodulation and channel measurement among the various RSs defined in the corresponding system, 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.

FIG. 7 shows an example of a UL subframe structure used in a wireless communication system.

Referring to FIG. 7, 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. 8 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. 8, the total system bandwidth (System BW) has a 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. 8, 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 of the component carriers are physically adjacent in FIG. 8, 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 .

9 is a diagram for explaining single carrier communication and multiple carrier communication. Particularly, FIG. 9A shows a subframe structure of a single carrier and FIG. 9B shows a subframe structure of multiple carriers.

Referring to FIG. 9A, 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. 9 (b), three 20 MHz CCs can be grouped into UL and DL, respectively, so that a bandwidth of 60 MHz can be supported. Each CC may be adjacent or non-adjacent to one another in the frequency domain. FIG. 9B 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 determined 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. 6 over the entire band regardless of the DL BW of the eNB. Accordingly, when the number of antenna ports of the eNB is 1, REs indicated by '0' in FIG. 6 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. 6 and may have a smaller density in the time axis or frequency axis than the existing 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 data demodulation 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).

10 is a diagram showing an example in which a cross carrier scheduling technique is applied. In particular, in FIG. 10, 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.

11 is a diagram illustrating a deployment scenario of a UE and a BS in an LTE and 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. 11 and the overlay model shown in the right side of FIG. or a co-located model.

In the case of the overlay model shown in the left side of FIG. 11, 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. 11, the pico / femto eNB can perform wireless communication with the Y terminal simultaneously using an authorized carrier and an 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.

12 is a block diagram showing the 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 wireless communication using a wireless 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. 12, 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 in 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. [

12, the base station 200 according to an exemplary 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. 12, 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 in 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 wireless signal to at least one of the terminal 100, the external device, and the server through the wireless LAN connection, 2 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. 12 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.

FIG. 13 shows a control region in which a PDCCH is transmitted in an LTE (-A) system. The control resign may be composed of 1 to 3 OFDM symbols (s) and may extend to 4 OFDM symbols when the system BW is 1.4 MHz. The PDCCH of the control region can be transmitted over 1 to 3 OFDM symbols (s) according to the size of the control region. And the PDCCH may be transmitted over the frequency axis or time axis within the control region.

Fig. 14- (a) relates to a procedure for control information and control channel transmission in LTE (-A). Each control information is subjected to rate matching according to the amount of resources (s) used for PDCCH transmission after attaching CRC according to the RNTI value according to the purpose and tailed biting convolutional coding. The PDCCHs (s) to be transmitted in a given subframe are multiplexed with PDCCHs using the CCE-based PDCCH structure to map resources to be transmitted. The number of CCEs used for one PDCCH is defined as the aggregation level. In LTE (-A), 1, 2, 4, and 8 can be used. FIG. 14- (b) is a diagram of CCE aggregation and multiplexing of a PDCCH, and shows a type of a CCE aggregation level used for one PDCCH and a CCE (s) transmitted in the corresponding control region.

15 is a diagram for setting up a PDCCH search space in the LTE (-A) system. In order to transmit the PDCCH to the UE, at least one search space per UE may exist in the control region. In the present invention, the search space refers to all the time-space resource combinations to which the PDCCH of the UE can be transmitted, and includes a common search space common to all terminals of 3GPP LTE (-A) Specific or UE-specific search space to which a specific UE must search. The common search space is set to monitor a PDCCH that is set so that all terminals in a cell belonging to the same base station are commonly found. A specific terminal search space is defined as a PDCCH allocated to each terminal in search space positions However, the search space between the UEs may be partially overlapped due to the limited control region to which the PDCCH can be allocated.

16 is a diagram showing a CORESET to which a PDCCH in a 3GPP NR system can be transmitted.

CORESET is a time-frequency domain in which a PDCCH, which is a control signal of a UE, is transmitted. A search space set for transmitting a PDCCH to a UE can be mapped into a CORESET. That is, the UE can receive only the time-frequency domain defined by CORESET and decode the PDCCH mapped therein without receiving the entire frequency band and attempting PDCCH decoding. Referring to FIG. 16, there can be only one CORESET in a cell. Accordingly, all the UEs connected to the corresponding cell can perform PDCCH decoding by receiving one CORESET configured to the UE. Multiple CORESETs can exist in a cell. When there are multiple CORESETs in a cell, each terminal can be configured to monitor one or more CORESET (s). The CORESET (s) allocated to a UE can be configured to overlap with each other over time-frequency resources. The UE can know the time-frequency domain occupied by the CORESET (s) configured in the UE itself from the Node B in the current slot. However, the area of the time-frequency occupied by the CORESET (s) not configured for the UE from the base station by the current slot may be unknown or may be known through additional signaling. Also, the UE can not know the time-frequency resource occupied by the PDCCH (s) dynamically allocated to the CORESET (s) configured to itself in the future slot (s) from the base station.

For convenience of description of the present invention, a PDCCH scrambled with a group common RNTI (or common control RNTI, CC-RNTI) already known by the UEs is referred to as a UE group common PDCCH or a common PDCCH for transmission to one or more UEs , And describes a PDCCH scrambled with a specific-UE RNTI that a specific UE already knows in order to transmit uplink scheduling information or downlink scheduling information to a specific UE, as a specific-UE PDCCH. RNTI, P-RNTI, RA-RNTI, and TPC-RNTI may be used as RNTIs used by one or more UEs in LTE (-A). There may be C-RNTI, SPS C-RNTI, etc. in the specific-terminal RNTI. Also, the resources that the UE performs blind decoding to find the UE group common PDCCH are called the group common search space, and the resources for which the UE performs the blind decoding to find the specific-terminal PDCCH are called the specific-terminal search space.

Referring to FIG. 17, in the 3GPP NR system, terminals can perform transmission / reception using a bandwidth that is smaller than or equal to the bandwidth of a carrier (or cell). For this purpose, the terminal can have a plurality of bandwidth parts by dividing the bandwidth of the carrier. Referring to Fig. 17- (a), the bandwidth parts can be divided without overlapping. One or more of the bandwidth parts that are not overlapped can be allocated and configured to the terminals. The terminals can transmit / receive to / from the base station by using allocated and configured bandwidth parts. Referring to FIG. 17- (b), Bandwidth parts can be divided by overlapping the bandwidth of carriers. At this time, one Bandwidth part may be configured to be included in another Bandwidth part. One or more bandwidth parts of the overlapping bandwidth parts may be allocated and configured to the terminals. The terminals can transmit / receive to / from the base station using one of the allocated and configured bandwidth parts.

Referring to FIG. 18, when a terminal receives a plurality of Bandwidth parts, at least one CORESET may be configured or assigned to each Bandwidth part. Referring to FIGS. 18- (a) and 18 (b), when Bandwidth parts are configured so as not to overlap with each other and Bandwidth parts are configured to overlap, the CORESET for each Bandwidth part is the time / Frequency resource region. In other words, CORESET # 1 for Bandwidth part # 1 exists within the PRB in the time / frequency resource area occupied by Bandwidth part # 1, and CORESET # 2 for Bandwidth part # It can exist within the PRB in the resource area. Referring to FIG. 18- (b), when the bandwidth parts are configured to overlap with each other, the PRBs occupied by the CORESET are located within a bandwidth part time / frequency resource area but may be located in different bandwidth parts. In other words, CORESET # 2 for Bandwidth part # 2 may overlap PRB in the time / frequency resource area occupied by Bandwidth part # 1.

In the NR system, slots and mini-slots are defined to satisfy various latency conditions. The definitions of slots and mini-slots are as follows. First, the basic transmission unit on the time axis in NR can be defined as a slot, and the number of OFDM symbols that can be allocated to one slot can be set differently according to the subcarrier spacing. When 15kHz is used as the reference subcarrier spacing The number of OFDM symbols in the slot of the slot may be 7 or 14. If the reference subcarrier spacing is different in the reference frame structure, for example, subcarrier spacing of 30 kHz is considered, the number of OFDM symbols per slot may be 14.

When the URLLC transmission and the eMBB data are transmitted to the scheduled time / frequency resource, transmission in mini-slot units can be performed. Here, the length of the mini-slot may be from "1 OFDM symbol" to "OFDM symbol length occupied in the slot-1". When the data length of URLLC is considered to be transmitted in units of 7 OFDM symbols considering two OFDM symbol units or slot sizes, the length of mini-slots in 2 OFDM symbols or 7 OFDM symbol units A multiplexing method of eMBB data transmission and URLLC transmission can be considered.

The base station may multiplex the eMBB data and the URLLC data to different UEs to transmit data suitable for the UE requesting the eMBB service less sensitive to the delay time and the UE requesting the delay time sensitive URLLC service . A UE requesting an eMBB service has a relatively large delay time required to be transmitted, and the data payload size to be transmitted is large, so that data can be received by scheduling based on a slot basis. However, since the UE requesting the URLLC service has a relatively small delay time and the data payload size to be transmitted is small, slot-based scheduling is inefficient or can not satisfy the delay time requirement. Therefore, a UE requesting a URLLC service can receive data by scheduling based on a mini-slot having a scheduling period shorter than a slot. To increase frequency efficiency, resources for URLLC and resources for eMBB can be dynamically allocated. That is, some of the resources used for eMBB transmission can be punctured and reused as resources for URLLC. The multiplexing scheme of eMBB data and URLLC data can be called preemption scheme. At this time, a UE punctured with resources is called an impacted UE, and a UE allocated resources for URLLC is called a preempting UE.

If the preemption for the transmission of the URLLC data described above occurs, the performance of the UE affected by the preemption may be seriously affected. For this purpose, the base station can inform the impacted UEs of a preemption indicator for indicating which time-frequency resource is preempted through the group common PDCCH or the specific-terminal PDCCH. When the preemption indicator is included in the group common PDCCH and transmitted, the group common PDCCH is scrambled with the group common RNTI, and the group common RNTI may be a value shared by a plurality of terminals monitoring the group common PDCCH. When the preemption indicator is included in the specific-terminal PDCCH, the specific-terminal PDCCH is scrambled with the specific-terminal RNTI, and the specific-terminal RNTI may be a unique value of the terminal monitoring the specific-terminal PDCCH.

The UE can apply the preemption information indicated by the preemption indicator indicated through the group common PDCCH only to the bandwidth segment mapped with the CORESET in which the group common PDCCH exists. In other words, in order to check whether the data channel or control channel transmitted in a certain bandwidth part of the UE is affected by the preemption, the group common PDCCH for finding the preemption indicator in the CORESET of the bandwidth part should be blind decoded. If the UE does not need to check whether the data channel or control channel transmitted in a specific bandwidth part is affected by the preemption, the UE does not have to search for the preemption indicator in the CORESET of the corresponding bandwidth part and thus can prevent energy waste caused by blind decoding have.

19 (a), when the Bandwidth parts are configured so as not to overlap with each other, the UE transmits the Bandwidth part (s) in the CORESET (s) of the scheduled Bandwidth part It can be assumed that a group common PDCCH for transmitting a preemption indicator to know the preemption of the UE and the related preemption information is transmitted. That is, the PDCCH for monitoring the preemption indicator for CORESET # 1 can be monitored on the assumption that the group common PDCCH that transmits the preemption indicator for knowing the preemption information of Bandwidth part # 1 is transmitted in CORESET # 1. The group common PDCCH that transmits a preemption indicator to know the preemption information of Bandwidth part # 2 can monitor the PDCCH to find a preemption indicator in CORESET # 2, assuming that it is transmitted in CORESET # 2. In an embodiment of the present invention, when a terminal has overlapping Bandwidth parts, a preemption indicator for knowing preemption information in the Bandwidth part is transmitted from a CORESET of each Bandwidth part it is assumed that the group common PDCCH is transmitted. That is, when the Bandwidth part # 1 is included in the Bandwidth part # 2, the group common PDCCH for transmitting the preemption indicator for knowing the preemption information of the Bandwidth part # 1 is assumed to be transmitted in the CORESET # 1 and the preemption indicator is found in the CORESET # The PDCCH for monitoring the preemption indicator of the bandwidth part # 2 can be monitored, and the PDCCH for the group common PDCCH for monitoring the preemption indicator for the CORESET # 2 can be monitored on the assumption that the PDCCH is transmitted in the CORESET # 2 .

In the example of FIG. 19, the preemption indicator is transmitted in the slot after the preemption is generated. However, the time relationship is not particularly limited. The transmission of the preemption indicator is performed when the slot in which the preemption occurs is referred to as slot #n Within the slot # n interval after the preemption occurs, or the next slot or slot # (n + k), where k can be a natural number greater than or equal to one.

In an embodiment of the present invention, when the Bandwidth parts are configured so as not to overlap with each other, the UE determines whether preamption of each Bandwidth part in the CORESET (s) of the Bandwidth part (s) in which the PDSCH is scheduled and preemption It can be assumed that the group common PDCCH for transmitting the indicator is transmitted. Referring to FIG. 20- (a), when the PDSCH of one UE is scheduled only in Bandwidth part # 1, the UE assumes a preemption indicator in CORESET # 1 on the assumption that a group common PDCCH that transmits a preemption indicator is transmitted only in CORESET # 1 (CORESET # 2) is configured to monitor CORESET # 2 on the assumption that the group common PDCCH that transmits information on the preemption of Bandwidth part # 1 is not transmitted in the other CORESET (for example, CORESET # 2) The UE may not monitor the PDCCH to find the preemption indicator in the corresponding CORESET # 2. Referring to FIG. 20- (b), when the PDSCH of one UE is scheduled only in Bandwidth part # 2, the UE assumes that a group common PDCCH that transmits a preemption indicator is transmitted only in CORESET # 2, and transmits a preemption indicator in CORESET # 2 The UE monitors the PDCCH for searching for the CORESET # 2, and assumes that the group common PDCCH for transmitting information on the preemption of the Bandwidth part # 2 is not transmitted in another CORESET (CORESET # 1 for example) The CORESET # 2 may not monitor the PDCCH to find the preemption indicator. Referring to FIG. 20- (c), when a PDSCH of one UE is scheduled to Bandwidth part # 1 and a bandwidth part # 2, the UE transmits a group common PDCCH for transmitting a preemption indicator for Bandwidth part # 1 in CORESET # 1 The UE monitors the PDCCH for finding the preemption indicator in CORESET # 1, assumes that the group common PDCCH for transmitting the preemption indicator for Bandwidth part # 2 is transmitted in CORESET # 2, The PDCCH for finding the indicator can be monitored.

In the example of FIG. 20, the preemption indicator is transmitted in the slot after the preemption occurs. However, the time relationship is not particularly limited. The transmission of the preemption indicator is performed when the slot in which the preemption occurs is referred to as slot #n Within the slot # n interval after the preemption has occurred or next slot or slot # (n + k), where k can be a natural number greater than or equal to 1.

In an embodiment of the present invention, when a PDSCH of a UE is transmitted over several Bandwidth parts when Bandwidth parts are overlapped to one UE, the Bandwidth part of the Bandwidth part of the smallest Bandwidth part including the PDSCH it is assumed that the group common PDCCH for transmitting the preemption indicator to know the preemption information and the related preemption information is transmitted and the UE can monitor the PDCCH for searching for the preemption indicator in the corresponding CORESET and the preemption indicator is not transmitted in the other CORESET Suppose that no other CORESET (s) will monitor the PDCCH to find the preemption indicator. When a Bandwidth part # 1 and a Bandwidth part # 2 are overlapped and a Bandwidth part # 1 is included in a Bandwidth part # 2, the UE determines whether the PDSCH of the UE is a Bandwidth part # 1 , The UE can monitor the PDCCH for searching for the preemption indicator in the corresponding CORESET on the assumption that the group common PDCCH for transmitting the preemption indicator to know the preemption information of the PDSCH is transmitted in the CORESET of the Bandwidth part # On the other hand, the UE assumes that the group common PDCCH for transmitting the preemption indicator for knowing the preemption information of the PDSCH is not transmitted from the CORESET of the Bandwidth part # 2, and the UE monitors the PDCCH for the preemption indicator in the CORESET of the Bandwidth part # 2 I can not. When a Bandwidth part # 1 and a Bandwidth part # 2 are overlapped and a Bandwidth part # 1 is included in a Bandwidth part # 2, a terminal transmits a Bandwidth part # 1 And the PDSCH is included in the Bandwidth part # 2, the group common PDCCH for transmitting the preemption indicator for knowing the preemption information of the PDSCH is assumed to be transmitted in the CORESET of the Bandwidth part # 2. You can monitor the PDCCH to find the preemption indicator. On the other hand, assuming that the group common PDCCH for transmitting the preemption indicator for knowing the preemption information of the PDSCH is not transmitted in the CORESET of the Bandwidth part # 1, the UE monitors the PDCCH for the preemption indicator in the CORESET of the Bandwidth part # 1 . When the Bandwidth part # 1 and the Bandwidth part # 2 are overlapped and the Bandwidth part # 1 is included in the Bandwidth part # 2, the terminal determines that the PDSCH of the UE is the Bandwidth part # 1 2, the group common PDCCH that transmits a preemption indicator for knowing the preemption information of the PDSCH is transmitted from the CORESET of the Bandwidth part # 2, and the UE transmits a preemption indicator to the CORESET of the corresponding bandwidth part # 2 it is possible to monitor the PDCCH for searching for the preemption indicator. On the other hand, in the CORESET of the Bandwidth part # 1, the UE assumes that the group common PDCCH for transmitting the preemption indicator for knowing the PDSCH preemption information is not transmitted, In CORESET # 1, the PDCCH for finding the preemption indicator may not be monitored.

In another embodiment of the present invention, when transmitting the preemption indicator to the specific-terminal PDCCH, the specific-terminal PDCCH including the preemption indicator is always transmitted in a predetermined CORESET regardless of whether or not the PDSCH of the terminal is scheduled to a certain bandwidth part .

Referring to Figs. 22- (a), 22- (b) and 22- (c), when the Bandwidth part (s) is configured not to overlap, the Bandwidth part (s) The PDCCH containing the preemption indicator indicating the preemption information of the PDSCH can always be transmitted in CORESET # 1.

Referring to Figs. 23- (a), 23- (b) and 23- (c), when the Bandwidth part (s) is configured to overlap, regardless of the Bandwidth part , The specific-terminal PDCCH including the preemption indicator indicating the preemption information of the PDSCH can always be transmitted in CORESET # 1.

In another embodiment of the present invention, when transmitting the preemption indicator to the specific-terminal PDCCH, the DCI payload length of the specific-terminal PDCCH including the preemption indicator may vary according to the bandwidth part (s) occupied by the PDSCH of the terminal. 22 and FIG. 23, when the PDSCH of the UE is included in two bandwidth parts than the DCI payload length of the specific-UE PDCCH including the preemption indicator when the PDSCH of the UE is included in one bandwidth part, The DCI payload length of the PDCCH of the specific-terminal including the indicator may be long.

In another embodiment of the present invention, when the preemption indicator is transmitted on the specific-terminal PDCCH, the DCI payload length of the specific-terminal PDCCH including the preemption indicator may vary according to the number of PRBs (s) occupied by the PDSCH of the terminal . 22 and 22, when the PDSCH of the UE occupies X PRB (s), the DCI payload length of the specific-UE PDCCH including the preemption indicator may increase or decrease in proportion to X. [ That is, the DCI payload length of the specific-terminal PDCCH including the preemption indicator may be ceil (kX) bits. Where k is a number between 0 and 1, and ceil (a) is the smallest natural number equal to or greater than a. The MS can deduce the length of the specific-terminal PDCCH including the preemption indicator according to the length of the PRB occupied by the PDSCH allocated to the MS, and perform blind decoding using the length.

24, in a CORESET in which a PDCCH for scheduling a PDSCH is transmitted, a base station transmits a preemption indicator, and a terminal determines that a preemption indicator is transmitted in a corresponding CORESET, Lt; RTI ID = 0.0 > PDCCH < / RTI > When the preemption indicator is transmitted on the group common PDCCH or transmitted on the UE specific PDCCH, the UE assumes that the preemption indicator is transmitted from the CORESET to which the UE has previously scheduled the CORESET to which the preemption indicator is transmitted. A group common PDCCH or a UE specific PDCCH for finding an indicator can be set to be monitored.

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 and apparatus for transmitting and receiving data between a terminal and a base station

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