KR20140096945A

KR20140096945A - Method and Apparatus of Transmitting and Receiving Orthogonal Demodulation Reference Signal in carrier of New Carrier Type

Info

Publication number: KR20140096945A
Application number: KR1020130046670A
Authority: KR
Inventors: 김선우
Original assignee: 인텔렉추얼디스커버리 주식회사
Priority date: 2013-01-28
Filing date: 2013-04-26
Publication date: 2014-08-06

Abstract

The present invention relates to an NCT in which a control region including a PDCCH does not exist, and a method for transmitting a demodulation reference signal having orthogonality in a carrier in which a base station is an NCT according to an embodiment of the present invention includes: Performing code division multiplexing on a demodulation reference signal to be mapped to a symbol overlapping with the PSS and the SSS to be allocated using an orthogonal code, and transmitting a downlink including the demodulation reference signal to which the code division multiplexing is applied .

Description

[0001] The present invention relates to a method and apparatus for transmitting and receiving a demodulation reference signal having orthogonality in a carrier which is a NCT (New Carrier Type)

The present invention relates to an NCT in which a control region including a PDCCH does not exist. And more particularly to a method and apparatus for transmitting and receiving a demodulation reference signal having orthogonality in a carrier which is an NCT.

As communications systems evolved, consumers, such as businesses and individuals, used a wide variety of wireless terminals. In a mobile communication system such as the current 3GPP family Long Term Evolution (LTE) and LTE-A (LTE Advanced), a high-speed and large-capacity communication system capable of transmitting and receiving various data such as video and wireless data, , It is required to develop a technology capable of transmitting large-capacity data based on a wired communication network. As a method for transmitting a large amount of data, a method of efficiently transmitting data through a plurality of element carriers can be used.

In this system, the time-frequency resource is divided into a region for transmitting a control channel (for example, a physical downlink control channel (PDCCH)) and a region for transmitting a data channel (for example, a Physical Downlink Shared CHannel (PDSCH) .

In order to improve the performance of a wireless communication system, technologies such as Multiple-Input Multiple-Output (MIMO) and Coordinated Multi-Point Transmission / Reception (CoMP) have been considered.

In the NCT (New Carrier Type) where there is no control area including PDCCH added as a new work item to 3GPP Rel-12, RRM measurement for NCT, DM-RS collision problem with PSS / SSS, (Radio Resource Management measurement, synchronized new carrier).

The present invention proposes a position change or a transmission pattern change method in order to avoid a collision with a DM-RS when a PSS / SSS exists in the NCT.

Also, the present invention proposes a method for avoiding a collision between the PSS / SSS and the DM-RS while maintaining the same position of the PSS / SSS and the DM-RS.

A method for transmitting a demodulation reference signal having orthogonality in a carrier in which a base station is an NCT according to an embodiment of the present invention is a method for transmitting a demodulation reference signal for a demodulation reference signal to be mapped to a symbol overlapped with a PSS and an SSS disposed in a downlink sub- Performing code division multiplexing using an orthogonal code, and transmitting a downlink including a demodulation reference signal to which the code division multiplexing is applied.

A method for receiving a demodulation reference signal having orthogonality in a carrier that is a NCT according to another embodiment of the present invention includes receiving a downlink including a demodulation reference signal, Wherein the demodulation reference signal is mapped to a symbol superimposed with a PSS and an SSS placed in a downlink subframe of the carrier and the demodulation reference signal is mapped to the PSS and the SSS and the demodulation reference signal, And the reference signal is code division multiplexed.

A base station for transmitting a demodulation reference signal having orthogonality in a carrier, which is an NCT according to another embodiment of the present invention, includes a receiver for receiving a signal from a terminal, a PSS and an SSS And a transmitter for transmitting a downlink signal including a demodulation reference signal to which the code division multiplexing is applied. The demodulation reference signal is demodulated by using a code division multiplexing method.

1 shows a communication system to which embodiments of the present invention are applied.
FIG. 2 shows a control region in which a control channel including a PDCCH, a PCFICH, and a PHICH are transmitted in one subframe, and a data region in which a data channel including a PDSCH is transmitted.
3 is an ePDCCH implementation scheme to which one embodiment of the present disclosure is applied.
4 shows the distributed transmission and the centralized transmission of the ePDCCH.
FIG. 5 shows the positions of PSS / SSS on a symbol of OFDM in the case of FDD and TDD.
FIG. 6 shows the positions of PBCHs on OFDM symbols.
FIG. 7 shows positions of subcarriers (resource elements) of PSS / SSS, PBCH for the entire bands of 20 MHz, 10 MHz, 5 MHz, 3 MHz and 1.4 MHz, respectively.
8 shows a symbol-based cyclic shifted eREG indexing for a PRB pair for a PRB pair when CRS port 0 is set when EPDCCH is used as an NCT structure.
Figure 9 shows the collision of PSS / SSS and DM-RS.
FIG. 10 illustrates code divisional multiplexing of PSS / SSS and DM-RS according to an embodiment of the present invention.
11 is a flowchart illustrating an operation of a base station according to an embodiment of the present invention.
12 is a flowchart illustrating an operation procedure of a terminal according to an embodiment of the present invention.
13 is a diagram illustrating a configuration of a base station according to an embodiment of the present invention.
14 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 shows a communication system to which embodiments of the present invention are applied.

Communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.

1, a communication system includes a user equipment (UE) 10 and a transmission point 20 for performing uplink and downlink communication with the terminal 10. [

The terminal 10 or user equipment (UE) in the present specification is a comprehensive concept of a user terminal in wireless communication. The terminal 10 or UE is a mobile terminal in the GSM, a mobile station (MS) in UT, User Terminal, SS (Subscriber Station), wireless device, and the like.

A transmission terminal 20 or a cell generally refers to a station that communicates with the terminal 10 and includes a base station, a Node-B, an evolved Node-B (eNB), a base transceiver station (BTS) System, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and the like.

In this specification, a transmission terminal 20 or a cell should be interpreted in a generic sense to indicate a partial area covered by a BSC (Base Station Controller) in a CDMA, a NodeB of a WCDMA, etc., and a RRH Which means any type of device capable of communicating with one terminal, such as a cell, a cell, a head, a relay node, a sector of a macro cell, a site, a microcell such as another femtocell, Used as a concept.

Herein, the terminal 10 and the transmission terminal 20 are used in a broad sense as a transmitting / receiving entity used to implement the technical or technical idea described in the present specification and are not limited to a specific term or word.

Although one terminal 10 and one transmission terminal 20 are shown in Fig. 1, the present invention is not limited thereto. One transmission terminal 20 can communicate with a plurality of terminals 10 and one terminal 10 can communicate with a plurality of transmission terminals 20. [

There is no limitation on a multiple access technique applied to a communication system, and the present invention is applicable to a CDMA (Code Division Multiple Access), a TDMA (Time Division Multiple Access), an FDMA (Frequency Division Multiple Access), an OFDMA (Orthogonal Frequency Division Multiple Access) -FDMA, OFDM-TDMA, and OFDM-CDMA.

In addition, the present invention can be applied to a TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, a Frequency Division Duplex (FDD) scheme in which different frequencies are used, It is applicable to the hybrid duplexing method.

In particular, embodiments of the present invention provide asynchronous wireless communications that evolve into LTE (Long Term Evolution) and LTE-Advanced (LTE-A) over GSM, WCDMA, and HSPA and synchronous wireless communications that evolve into CDMA, CDMA- Wireless communication field, and the like. It should be understood that the present invention is not limited to or limited to a particular wireless communication field and should be construed as including all technical fields to which the spirit of the present invention may be applied.

Referring to FIG. 1, a terminal 10 and a transmission terminal 20 can perform uplink and downlink communications.

The transmission terminal 20 performs downlink transmission to the terminal 10. The transmission unit 20 may transmit a Physical Downlink Shared Channel (PDSCH), which is a primary physical channel for unicast transmission. In addition, the transmission terminal 20 transmits scheduling approval information for transmission on the uplink data channel (for example, a physical uplink shared channel (PUSCH)), downlink control information such as scheduling required for PDSCH reception, A Physical Downlink Control Channel (PDCCH) for transmitting information, a Physical Control Format Indicator Channel (PCFICH) for transmitting an indicator for distinguishing between PDSCH and PDCCH regions, an uplink transmission And a physical HARQ indicator channel (PHICH) for transmission of HARQ (Hybrid Automatic Repeat reQuest) acknowledgment to the BS. Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

The transmission terminal 20 transmits a cell-specific reference signal (CRS), a MBSFN reference signal (MBSFN-RS), a UE-specific reference signal (DM-RS), a position reference signal (PRS), and a CSI reference signal (CSI-RS).

Meanwhile, one radio frame or radio frame is composed of 10 subframes, and one subframe is composed of two slots. The radio frame has a length of 10 ms and the subframe has a length of 1.0 ms. In general, a basic unit of data transmission is a subframe unit, and downlink or uplink scheduling is performed in units of subframes.

One slot may have a plurality of OFDM symbols in the time domain and at least one subcarrier in the frequency domain. For example, the slot may include 7 OFDM symbols in the time domain (in case of Normal Cyclic Prefix) or 6 (in case of Extended Cyclic Prefix) and 12 subcarriers in the frequency domain. The time-frequency domain defined by one slot may be referred to as a resource block (RB), but is not limited thereto.

2 shows a control region 201 in which a control channel including a PDCCH, a PCFICH, and a PHICH are transmitted in one subframe, and a data region 202 in which a data channel including a PDSCH is transmitted. In Fig. 2, the horizontal axis represents time and the vertical axis represents frequency. FIG. 2 shows one sub-frame (1 ms) on the time axis and one channel (for example 1.4, 3, 5, 10, 15, or 20 MHz) on the frequency axis.

The PCFICH consists of 2 bits of information corresponding to the OFDM symbol, which is the size of the control area 201, and is encoded into a 32-bit code word. The encoded bits are scrambled using cell-specific and sub-frame-specific scrambling codes to randomize intercell interference and then modulated with Quadrature Phase Shift Keying (QPSK) to form 16 resource elements Lt; / RTI > The PCFICH is always mapped to the first OFDM symbol of each subframe. When the PCFICH is mapped to the first ODFM symbol of the subframe, it is divided into four groups, and the groups are well separated and mapped in the frequency domain to obtain excellent diversity as a whole.

The PDCCH (control information) is used to transmit downlink control information (DCI) such as scheduling decisions and power control commands. As an example, in LTE / LTE-A, DCI format 0 and DCI format 4 are used for uplink grant. The DCI format 1 / 1A / 1B / 1C / 1D / 2 / 2A / 2B / 2C is used for downlink scheduling assignment. And DCI format 3 / 3A is used for power control.

Each DCI message payload is accompanied by a cyclic redundancy check (CRC), and an RNTI (Radio Network Temporary Identifier) for identifying the UE is included in the CRC calculation process. After appending the CRC, the bits are encoded into a tail-biting convolutional code, and are matched to the amount of resources used for PDCCH transmission through rate matching.

The PDCCH may be transmitted in a common search space or a UE specific search space of the control domain 201. [ Each terminal 10 searches for a PDCCH through blind decoding in a common search space commonly allocated to UEs in a cell and in a UE-specific search space assigned to itself, and upon confirming PDCCH reception, It is possible to perform control based on the control information transmitted through the network.

Meanwhile, the LTE / LTE-A system defines the use of a plurality of unit carriers (Component Carriers) as a scheme for expanding the bandwidth to satisfy the system requirements, that is, a high data rate. In this case, one CC can have a maximum bandwidth of 20 MHz, and resources can be allocated within 20 MHz according to the corresponding service. However, this is only one example according to the process of implementing the system. .

In order to increase the data transmission speed, technologies such as a Multiple Input / Multiple Output (MIMO), a Coordinated Multiple Point (CoMP), and a relay node have been proposed. It is necessary to transmit more control information in the same transmission terminal as the base station.

However, when the size of the control region in which the PDCCH is transmitted is limited, a method of increasing the transmission capacity of the PDCCH can be considered as a method of transmitting control information to be transmitted through the PDCCH in the data area in which the PDSCH is transmitted. This method can support a large PDCCH capacity without reducing the reception reliability of the PDCCH. Control information corresponding to a PDCCH transmitted in a data region, for example, a PDSCH region, may be referred to as extended control information (Extended PDCCH, ePDCCH, X-PDCCH) or PDCCH-A (PDCCH-Advanced) Hereinafter, ePDCCH will be collectively described. The ePDCCH is also used for the R-PDCCH, which is the control channel for the relay. That is, the ePDCCH is a concept including both a control channel for relay and a control channel for inter-cell interference control. According to an embodiment of the present invention, the ePDCCH can be allocated to a data area (data channel area) of an arbitrary subframe.

The above-described ePDCCH is a new type of PDCCH considered in the Rel-11 LTE system, and it is necessary to allocate uplink control information (i.e., PUCCH) that can be caused by introducing the new PDCCH.

3 is an ePDCCH implementation scheme to which one embodiment of the present disclosure is applied.

The legacy PDCCH for the existing Rel-8/9/10 UE is transmitted to the legacy PDCCH region and the upper layer signaling or the SI information is transmitted from the Rel-11 UE to the legacy PDCCH region. A mode in which blind decoding is performed for only the e-PDCCH region (E-PDCCH region) can be considered.

According to the present embodiments, a new type carrier (NTC), Coordinated Multipoint Transmission / Reception (CoMP), and a downlink MIMO (Multi-input) are used in Carrier Aggregation (CA) in 3GPP LTE / EPDCCH for multi-output can be allocated to a PDSCH (Physical Downlink Shared Channel) which is a data area.

In this specification, allocation of control information is used in the same sense as allocation of a control channel. In other words, the allocation of control channels in this specification means allocating control information to resource elements.

At this time, the control channel is allocated in units of PRB (Physical Resource Block) pairs corresponding to two slots, i.e., one subframe, and PDSCH and ePDCCH can not be simultaneously allocated to one PRB pair. In other words, PDSCH and ePDCCH can not be multiplexed in one PRB pair.

Meanwhile, control information or control channels of two or more UEs may be allocated to two or more PRB pairs or may be allocated in one PRB pair to multiplex control information of UEs.

4 shows the distributed transmission and the centralized transmission of the ePDCCH.

Referring to FIG. 4, when multiplexing the control information of the UEs, one eCCE may be allocated to two or more PRB pairs in a distributed manner or localized in one PRB pair. The former case is referred to as a distributed transmission or distributed type (410 in FIG. 4), and the latter case is referred to as a centralized transmission or centralized type (420 in FIG. 4).

Localized transmission improves performance in low-speed movement. Distributed transmission increases control information in the control area during high-speed movement. Performance is improved over the transmitted PDCCH.

Meanwhile, it may support a common search space (CSS) in connection with a search space. RNTI, P-RNTI, RA-RNTI, TPC-PUCCH-RNTI, and TPC-PUSCH-RNTI, which can transmit a common RNTI (Common RNTI).

According to the trend of standardization of 3GPP LTE-Advanced, various discussions about carriers are proceeding. One of them is a new type of carrier (NCT).

The NCT is a primary CC of a component carrier (CC) (hereinafter referred to as "CC") merged through a carrier aggregation (CA) Refers to a sub CC that reduces overhead to increase the payload size in a secondary CC, that is, an element carrier that does not include a control region.

These NCTs are divided into Standalone NCT (S-NCT) and Non-standalone NCT (NS-NCT) types. Non-standalone NCT (NS-NCT) In the NCT, a Physical Downlink Control Channel (PDCCH), a Physical HARQ Indicator Channel (PHICH), a Physical Control Format Indicator Channel (PCFICH), and a Cell-Specific Reference Signal (CRS) ) Will not be transmitted.

The transmission terminal 20 transmits a cell-specific reference signal (CRS), a MBSFN reference signal (MBSFN-RS), a terminal-specific reference signal (DM-RS), a Positioning Reference Signal (PRS), and a CSI-reference signal (CSI-RS).

The transmission terminal 20 transmits a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) for synchronization with a base station and cell identification of a corresponding base station, (Hereinafter referred to as 'SSS') to at least one specific RB (Resource Block) in at least one subframe of one radio frame. At this time, the transmission terminal 20 has side effects such as interference with the user equipment (UE) (ICIC), conflict with setting of DM-RS (Demodulation Reference Signal, DMRS) The position of the PSS / SSS for the asynchronous NCT, which is one of the CCs not including the control region, can be changed on the time axis (symbol axis) as described below.

Meanwhile, the transmission terminal 20 will not transmit a cell-specific reference signal (CRS) in the downlink of the NCT. Instead, the transmitting end 20 may transmit a tracking reference signal (TRS). TRS can be regarded as a reduced CRS (CRS) which is transmitted in 5ms cycle based on the existing antenna port 0 and Rel.8 sequence of CRS. The transmission terminal 20 can also transmit a UE-Specific Reference Signal (DM-RS) and a CSI-RS (CSI-RS) signal in the NCT.

Therefore, since the CRS is not transmitted, the basic demodulation can be performed based on the DM-RS, so that the position of the PSS / SSS can be moved to another OFDM symbol in order to solve the collision problem between the PSS / SSS and the DM- have. The PBCH transmission pattern based on the DM-RS will be described in detail below.

FIG. 5 shows the positions of PSS / SSS on a symbol of OFDM in the case of FDD and TDD.

Referring to FIG. 5, in the case of FDD, the PSS is transmitted to the last symbol of the first slot of the subframes 0 and 5, and the SSS is transmitted to the second symbol at the end of the same slot.

In case of TDD, the PSS is transmitted in the third symbol (i.e., DwPTS) of subframes 1 and 6, and the SSS is transmitted in the last symbols of subframes 0 and 5.

FIG. 6 shows the positions of PBCHs on OFDM symbols.

Referring to FIG. 6, the PBCH is mapped to four subframes. The PBCH is mapped to the first four symbols of the second slot of subframe 0 of each radio frame in a normal CP and an extended CP.

FIG. 7 shows positions of subcarriers (resource elements) of PSS / SSS, PBCH for the entire bands of 20 MHz, 10 MHz, 5 MHz, 3 MHz and 1.4 MHz, respectively.

Referring to FIGS. 5 and 7, in the case of FDD, the PSS is matched to 72 subcarriers in the center of the entire band. Therefore, the PSS occupies 72 resource elements in the center except DC subcarriers in subframes 0 and 5. The SSS occupies 72 Resource Elements in the middle except the DC subcarriers in subframes 0 and 5.

In the case of TDD, the PSS occupies 72 resource elements in the center except DC subcarriers in subframes 1 and 6. In the same way as FDD, in the case of TDD, the SSS occupies 72 resource elements in the center excluding DC subcarriers in subframes 0 and 5.

Referring to FIGS. 6 and 7, the PBCH is transmitted over 72 subcarriers in the center of the entire band in the first four symbols of the second slot of subframe 0.

However, after the cell search process, the UE transmits a master information block (MIB), which is system information, through a physical broadcast channel (PBCH) in a control signal, and after the system information is received and decoded, the UE performs a random- To the cell.

FIG. 8 shows a symbol-based cyclic shifted eREG indexing for a PRB pair for a PRB pair when a CRS port (port) 0 is set when an EPDCCH is used as an NCT structure.

Even if another CRS port is set, a symbol-based cyclic shifted eREG indexing for a PRB pair may be performed as shown in FIG. 7 regardless of the RE position and number of CRSs.

However, since the CRS is not transmitted in the NCT, a problem may arise in reception and demodulation of a control channel such as a conventional PBCH based on CRS. However, the CRS may be transmitted at a cycle of 5 ms, or may be transmitted only in a specific frequency band, or the TRS may be transmitted in a combination of both.

Meanwhile, the PBCH is transmitted on the center 6PRB of the second slot of the subframe 0 of each radio frame.

A UE may not only access a system for the first time but also a plurality of elements merged through handover to support cell reselection and mobility and through Carrier Aggregation (CA) And carries out a cell access procedure even when it finds a synchronization for a carrier wave (hereinafter, referred to as 'CC').

The cell search process consists of PSS detection and SSS detection to obtain frequency and symbol synchronization for the cell, thereby obtaining frame / slot synchronization of the cell and determining the cell ID. On the other hand, the NCT may perform this process either in parallel with the PSS / SSS or via another signal.

If the cell synchronization is obtained and the cell ID is determined, a confirmation step of whether the corresponding cell is the NCT or the LCT is performed and the TRS is confirmed, thereby performing RRM measurement or PBCH channel demodulation. If the CRS is not transmitted as described above, PBCH channel demodulation is performed based on the DM-RS. The PBCH channel contains system information.

Therefore, PSS / SSS detection and PBCH detection are the basis for the cell access process according to the cell search.

In order to avoid collision between the PSS / SSS and the DM-RS, the position of the PSS / SSS can be moved on the time axis or DM-RS puncturing can be performed.

However, if a DM-RS is punctured, a channel estimation error may occur in a PBCH that estimates a channel based on a DM-RS, and this channel estimation error may be particularly serious for a UE moving at high speed. One way to solve this channel estimation error is to change the PBCH channel mapping position on the time axis.

In order to avoid collision with DM-RS when PSS / SSS is present in NCT, it is suggested to move to another OFDM symbol position, DM-RS puncturing, and examples of PBCH transmission pattern according to DM-RS pattern have.

In order to avoid a collision with the DM-RS when there is a PSS / SSS in the NCT, the present invention determines whether to move to another OFDM symbol position, DM-RS puncturing, and a PBCH transmission pattern according to a DM- SSS and DM-RS, while maintaining the same position as the existing PSS / SSS and DM-RS.

Figure 9 shows the collision of PSS / SSS and DM-RS.

As shown in FIG. 9, an interference / collision problem between the PSS / SSS and the DM-RS occurs due to duplication of the same location / location. That is, the DM-RS shown in 910 of FIG. 9 and the PSS / SSS in the 0/5 sub-frame of 920 are allocated to symbols on the same time axis. Meanwhile, since the location of the PSS / SSS or the DM-RS is changed, a method for avoiding such a problem is suggested. Of course, in another embodiment, it is also possible to consider transmitting a signal so that it can be discriminated instead of changing the position of the DM-RS.

Therefore, in one embodiment of the present invention, the PSS / SSS and the DM-RS are subjected to code divisional multiplexing without changing the positions of the PSS / SSS or the DM-RS in the NCT, And the like.

To support MU-MIMO as described in detail below, DM-RS is multiplexed using orthogonal sequences when mapping to complex demodulation symbols.

Antenna port (substantially the same applies to antenna port 5)

, The sequence r (m) of the DM-RS related to the PDSCH can be defined by the following equation (1).

In Equation (1)

May be 110 as the maximum downlink bandwidth in units of resource blocks (RBs). The pseudo-random sequence c (i) can be initialized as shown in Equation (2).

In Equation (2), n _s may have a value of 0 to 19 as a slot number. The _SCID is a scrambling identity and may have a value of 0 or 1.

The value of

Is not provided by the upper layer or DCI format 1A is used as the DCI.

), And in other cases

to be. According to

Equations

1 and 2, the DM-RS may have pseudo orthogonality when the values of n _SCID are different from each other.

Antenna port (substantially the same applies to antenna port 5)

, A part of the DM-RS in the PRB (Physical Resource Block) having the frequency domain index n _PRB

r (m) is mapped to the complex demodulation symbols of Equation (3) in a subframe according to a normal cyclic prefix (CP).

The symbol number l and the subcarrier number k of the resource element RE to which the sequence r (m) of the DM-RS related to the PDSCH is mapped can be determined as shown in Equation (4).

&Quot; (4) "

In Equation 4,

Is the resource block size in the frequency domain expressed by the number of subcarriers, n _PRB is the physical resource block number, and n _s is the slot number. In this case,

Can be given in Table 1 below.

On the other hand, a part of the DM-RS

r (m) is mapped to the complex demodulation symbols of Equation (5) in a subframe according to an extended cyclic prefix (CP).

The symbol number l and the subcarrier number k of the resource element RE to which the sequence r (m) of the DM-RS related to the PDSCH is mapped can be determined according to Equation (6).

In this case,

Can be given in Table 2 below.

The present invention can avoid collision between PSS / SSS and DM-RS by code divisional multiplexing of PSS / SSS and DM-RS without changing the position of PSS / SSS or DM-RS in NCT . For example, an orthogonal sequence may be further used when mapping the DM-RS to the complex demodulation symbols in the position duplication / collision of the PSS / SSS and the DM-RS.

FIG. 10 illustrates code divisional multiplexing of PSS / SSS and DM-RS according to an embodiment of the present invention. FIG. 10 is a diagram illustrating the orthogonality between the DM-RS signal and the PSS / SSS by applying the OCC of Table 1 to the DM-RS when the PSS / SSS and the DM-RS are mapped to the same symbols, Thereby eliminating interference. As a result, even if the DM-RS and the PSS / SSS are provided to the same symbol, the terminal can distinguish the DM-RS and the PSS / SSS.

9, since code division multiplexing is applied, interference between the DM-RS and the PSS / SSS located in the same symbol can be avoided.

Specifically, a part of DM-RS

Is mapped to the complex demodulation symbols of Equation (7) in a subframe according to a normal cyclic prefix (CP).

In Equation (7), W (l) denotes w (x, y), x denotes the position of the symbol of the corresponding slot in the corresponding subframe, and y denotes the position of the subcarrier.

Therefore, if w (x, y) is w (5,0), w (6,0), w (5,1) W (5,10), w (6,10), w (5,10), w (6,5) , 11) and w (6, 11)

The additional orthogonal sequence, e.g., [1,1, -1, -1], is further multiplied by the complex demodulation symbols, so that the DM-RS can be code division multiplexed with the PSS / SSS.

The transmission end may transmit the orthogonal code used for the code division multiplexing of the DM-RS and the PSS / SSS to the mobile station implicitly or explicitly (RRC signaling or system information), but without transmitting the orthogonal code, Orthogonal codes may be sequentially blind decoded. In other words, as shown in FIG. 10, when DM-RS and PSS / SSS are code division multiplexed using 8 orthogonal codes, 8 orthogonal codes can be sequentially used for blind decoding.

In addition, the UE may be transmitted with a scheme of sequentially blind decoding using 8 orthogonal codes for the DM-RS located at the same position as the PSS / SSS, and information on orthogonal codes to be transmitted.

The sequential blind decoding method confirms that the UE decodes the eight orthogonal codes of Table 1 one by one, which may lead to a temporal load on the UE side. An embodiment of the antenna port and the orthogonal code is as shown in Table 1, and if explicitly indicated such as RRC, an orthogonal code can be included in the RRC.

As an embodiment of a method of explicitly transmitting orthogonal codes, information indicating an orthogonal code may be included in the RRC. Next, only orthogonal code information of some of the eight orthogonal codes of Table 8 is included in the RRC, and the UE can perform blind decoding using only a part of the orthogonal code information. This can be seen as transmitting an orthogonal code group. That is, only orthogonal code information of a part of Table 1 can be generated as an orthogonal code group and included in the RRC, thereby reducing the number of times that the UE performs blind decoding. For example, if the base station transmits only a part of orthogonal codes to the RRC as shown in Table 3 below among eight orthogonal codes of Table 1, the terminal can perform blind decoding using only the asynch codes of Table 3. [ In this case, the number of times of blind decoding can be reduced by a maximum of four. The UE can perform blind decoding using Table 3 until the orthogonal codes are transmitted again to the RRC.

[Table 3]

Compared with Table 1 above, Table 3 contains only some orthogonal code information. The orthogonal code group information including the orthogonal code is transmitted as shown in Table 1 or Table 3, and the terminal can perform blind decoding. Also, the UE may explicitly include the information indicating the orthogonal code in the RRC so that the UE can confirm the DM-RS using the orthogonal code.

In order to calculate the group as shown in Table 1 in Table 1, the base station can perform a process of selecting a sequence allocable for a predetermined period in the base station. The sequence can be selected by selecting the DM-RS suitable for the UE, and also considering the orthogonal code to be applied to the PSS / SSS of the overlapped location. The method of selecting and transmitting a group from among the sequences of Table 1 may vary according to the promise of the BS and the MS or the MS.

11 is a flowchart illustrating an operation of a base station according to an embodiment of the present invention.

The base station of FIG. 11 shows a process of transmitting a demodulation reference signal in a carrier which is an NCT. The base station confirms the type of the carrier to which the demodulation reference signal is to be transmitted (S1110). If it is the NCT (S1120), the orthogonal code to be applied to the demodulation reference signal is selected (S1130), and the demodulation reference signal is code division multiplexed and mapped using the selected orthogonal code (S1140). This process means that code division multiplexing is performed using an orthogonal code for a demodulation reference signal to be mapped to a symbol overlapping with the PSS and SSS arranged in the downlink subframe of the carrier. The base station transmits the downlink including the mapped demodulation reference signal (S1150). That is, the base station transmits the downlink including the demodulation reference signal to which the code division multiplexing is applied. On the other hand, if not the NCT, the demodulation reference signal is mapped in a legacy manner (S1160).

11, when a base station transmits information indicating an orthogonal code, the base station may transmit information indicating the orthogonal code by including it in the RRC. Also, as described in the embodiment of Table 3, the base station can transmit orthogonal code groups. That is, when two or more orthogonal code group information including the orthogonal code is included in the RRC and transmitted, the UE can perform blind decoding using only orthogonal codes in the group.

Where the orthogonal code may be one of the orthogonal sequences of Table 1.

12 is a flowchart illustrating an operation procedure of a terminal according to an embodiment of the present invention. The terminal of FIG. 12 shows a process of receiving a demodulation reference signal in a carrier which is an NCT.

The terminal receives the downlink including the demodulation reference signal (S1210). Then, the type of the carrier to which the demodulation reference signal is transmitted is confirmed (S1220). If it is NCT (S1230), the UE confirms the orthogonal code by applying the orthogonal code to the demodulation reference signal included in the downlink subframe (S1240). Herein, the demodulation reference signal is mapped to a symbol overlapped with a PSS and an SSS disposed in a downlink subframe of the carrier, and the PSS and the SSS and the demodulation reference signal are code division multiplexed.

The process of confirming the demodulation reference signal arranged in the downlink subframe of the carrier using the orthogonal code of S1240 will be described in more detail as follows.

First, when a base station transmits information indicating an orthogonal code, the orthogonal code can be used. That is, the UE can receive the RRC including the information indicating the orthogonal code and confirm the demodulation reference signal using the orthogonal code of the indication information. If one orthogonal code is not indicated or there is no indication information, the terminal must perform blind decoding. Therefore, the checking step of S1240 includes a process in which the UE blindly decodes the demodulation reference signal using a plurality of orthogonal codes. As shown in Table 3, when the base station transmits orthogonal code groups, the number of blind decodings is reduced. That is, when the UE receives the RRC including orthogonal code group information for a plurality of orthogonal codes to be subjected to the blind decoding prior to the confirming step, the UE performs blind decoding only among the orthogonal codes in the groups Thereby confirming the demodulation reference signal.

Where the orthogonal code may be one of the orthogonal sequences of Table 1.

13 is a diagram illustrating a configuration of a base station according to an embodiment of the present invention.

13, a base station 1300 according to another embodiment includes a control unit 1310, a transmission unit 1320, and a reception unit 1330.

The controller 1310 controls the overall operation of the base station according to the structure and operation of the NCT necessary for performing the above-described present invention.

The transmitting unit 1320 and the receiving unit 1330 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

In more detail, the base station of FIG. 13 transmits a demodulation reference signal having orthogonality in the carrier, which is the NCT shown in FIGS. 10 and 11. The receiving unit 1330 receives a signal from the UE, and the control unit 1310 demodulates the demodulated reference signal to be mapped to a symbol overlapped with the PSS and the SSS allocated in the downlink sub-frame of the carrier using code division multiplexing . The transmitter 1320 transmits the downlink including the demodulation reference signal to which the code division multiplexing is applied.

14 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

14, a user terminal 1400, i.e., a terminal according to another embodiment includes a receiving unit 1430, a control unit 1410, and a transmitting unit 1420. Referring to FIG.

The receiver 1430 receives downlink control information, data, and a message from the base station through the corresponding channel.

In addition, the controller 1410 controls the overall operation of the terminal according to the structure and operation of the NCT in order to perform the above-described present invention.

The transmitter 1420 transmits downlink control information, data, and a message to the base station through the corresponding channel.

In more detail, the user terminal of FIG. 14 receives and confirms a demodulation reference signal having orthogonality in the carrier, which is the NCT shown in FIGS. 10 and 12. The receiver 1330 receives the downlink including the demodulation reference signal, and the controller 1410 identifies the demodulation reference signal allocated to the downlink subframe of the carrier using the orthogonal code. At this time, the demodulation reference signal is mapped to a symbol overlapped with PSS and SSS arranged in a downlink sub-frame of the carrier, and the PSS and SSS and the demodulation reference signal are code division multiplexed. The transmitter 1420 transmits a signal to the base station.

When the demodulation reference signal, which is an embodiment of the present invention, overlaps with a signal such as PSS / SSS, interference between a demodulation reference signal and a PSS / SSS signal can be solved when code division multiplexing is performed by applying an orthogonal code. That is, by implementing the present invention, collision between the PSS / SSS and the DM-RS can be avoided while maintaining the same position of the PSS / SSS and the DM-RS.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims

A method for transmitting a demodulation reference signal having orthogonality in a carrier, the carrier being a New Carrier Type (NCT)
Code division multiplexing is performed using an orthogonal code on a demodulation reference signal to be mapped to a symbol overlapping with a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) arranged in a downlink subframe of the carrier step; And
And transmitting the downlink including the demodulation reference signal to which the code division multiplexing is applied.

The method according to claim 1,
Further comprising transmitting information indicating the orthogonal code in an RRC (Radio Resource Control).

The method according to claim 1,
Further comprising: transmitting at least two orthogonal code group information including the orthogonal code in an RRC (Radio Resource Control).

The method according to claim 1,
Wherein the orthogonal code is one of the following orthogonal sequences.

A method for receiving a demodulation reference signal having orthogonality in a carrier, the carrier being a New Carrier Type (NCT)
Receiving a downlink including a demodulation reference signal; And
And checking a demodulation reference signal arranged in a downlink subframe of the carrier using an orthogonal code,
The demodulation reference signal is mapped to a symbol superimposed on a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) arranged in a downlink sub-frame of the carrier, and the PSS and the SSS and the demodulation reference signal are code division multiplexed Lt; / RTI >

6. The method of claim 5,
Further comprising receiving an RRC (Radio Resource Control) including information indicating the orthogonal code.

6. The method of claim 5,
Wherein the verifying step further comprises blind decoding the demodulation reference signal using a plurality of orthogonal codes.

8. The method of claim 7,
Before the confirming step
Further comprising receiving an RRC (Radio Resource Control) including orthogonal code group information for a plurality of orthogonal codes to be subjected to the blind decoding.

6. The method of claim 5,
Wherein the orthogonal code is one of the following orthogonal sequences.

A base station for transmitting a demodulation reference signal having orthogonality in a carrier which is a New Carrier Type (NCT)
A receiving unit for receiving a signal from the terminal;
Code division multiplexing is performed using an orthogonal code on a demodulation reference signal to be mapped to a symbol overlapping with a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) arranged in a downlink subframe of the carrier A control unit; And
And a transmitter for transmitting a downlink including a demodulation reference signal to which the code division multiplexing is applied.