JP2015164340A - Method and device for receiving downlink signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for efficiently utilizing downlink resources in a radio communication system.SOLUTION: The present invention relates to a method and a device for receiving a downlink signal in a radio communication system, specifically, relates to the method comprising the steps of: receiving first control information for downlink scheduling in the first slot of a resource block (RB) pair in which the first control information includes allocation information on one or more resource units; receiving data at the second slot of the RB pair when the allocation information on a resource unit including the RB pair with the first control information has a first value; and attempting to detect second control information for uplink scheduling at the second slot of the RB pair when the allocation information on the resource unit including the RB pair with the first control information has a second value, and relates to the device for the same.

Description

  The present invention relates to a wireless communication system, and more particularly, to a method for receiving a downlink signal and an apparatus for receiving the downlink signal.

  Wireless communication systems are widely deployed to provide various communication services such as voice and data. Generally, a wireless communication system is a multiple access system that can share available system resources (bandwidth, transmission power, etc.) and support communication with multiple users. Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) system, Single Carrier Frequency Division Multiple Access (SC-FDMA) system, Multi Carrier Frequency Division Multiple Access (Multi Carrier Frequency Division Multiple Access) : MC-FDMA) system.

  An object of the present invention is to provide a method for efficiently using downlink resources in a wireless communication system and an apparatus for efficiently using downlink resources in a wireless communication system.

  The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned are those described below, which are normal in the technical field to which the present invention belongs. It will be clearly understood by those who have knowledge.

  As one aspect of the present invention, in a method for receiving a downlink signal in a wireless communication system, first control information for downlink scheduling is received in a first slot of a resource block (RB) pair; Here, when the first control information includes allocation information regarding one or more resource units, and the allocation information regarding a resource unit including an RB pair with the first control information has a first value, When data is received in the second slot of the RB pair, and the allocation information related to the resource unit including the RB pair with the first control information has a second value, the second slot of the RB pair A method is provided that attempts to detect second control information for uplink scheduling.

  As another aspect of the present invention, in a communication device configured to receive a downlink signal in a wireless communication system, a radio frequency (RF) unit and a microprocessor are provided, and the microprocessor includes: First control information for downlink scheduling is received in a first slot of a resource block (RB) pair, wherein the first control information is allocation information related to one or more resource units. And the first control information is received in the second slot of the RB pair when the allocation information regarding the resource unit including the RB pair having the first control information has a first value, and the first control information If the allocation information for the resource unit including a certain RB pair has a second value, the second slot of the RB pair Configured in such attempts to detect the second control information for uplink scheduling, the communication device is provided.

  Preferably, the resource unit allocation information includes a bitmap for resource allocation, and each bit indicates whether to allocate a resource to a corresponding RB or resource block group (RBG).

  Preferably, the second control information is present in the second slot of the RB pair when the allocation information regarding the resource unit including the RB pair with the first control information has a second value.

  Preferably, the first value is 1 and the second value is 0.

  Preferably, the detection of the second control information is performed under an assumption that an aggregation level of the second control information is lower than a control level of the first control information. .

  Preferably, the detection of the second control information includes the search space set in advance for the second control information and the resource unit in which the allocation information has a second value. Only done on overlapping resources.

  Preferably, the communication apparatus receives information on the arrangement of the second control information on the resource of the second slot through higher layer signaling.

  According to the embodiment of the present invention, it is possible to efficiently use downlink resources in a wireless communication system.

  The effects obtained by the present invention are not limited to the effects mentioned above, and other effects that are not mentioned will be apparent to those having ordinary knowledge in the technical field to which the present invention belongs from the following description. Will be understood.

It is a figure which shows the structure of the radio | wireless frame in 3GPP system. It is a figure which shows the resource grid (resource grid) of a downlink slot. It is a figure which illustrates the structure of a downlink sub-frame. It is a figure which shows the structure of the uplink sub-frame used by a system. It is a figure which shows the process which transmits a signal by a multi-antenna system. It is a figure which shows the structure of a demodulation reference signal (DeModulation Reference Signal: DMRS). It is a figure which shows the mapping with a virtual resource block (Virtual Resource Block: VRB) and a physical resource block (Physical Resource Block: PRB). It is a figure which shows type 0 resource allocation (Resource Allocation: RA). It is a figure which shows RA of type 1. It is a figure which shows type 2 RA. It is a figure which shows the radio | wireless communications system containing a relay. It is a figure which shows the backhaul communication using a multimedia broadcast single frequency network (Multi-Media Broadcast over a Single Frequency Network: MBSFN) sub-frame. It is a figure which divides and shows the resource comprised by frequency-time arbitrarily. It is a figure which divides and shows the resource comprised by frequency-time arbitrarily. It is a figure which shows the example which arrange | positions and demodulates R-PDCCH / (R-) PDSCH. It is a figure which shows the example which arrange | positions and demodulates R-PDCCH / (R-) PDSCH. It is a figure which shows the example which arrange | positions and demodulates R-PDCCH / (R-) PDSCH. It is a figure which shows the example which divided | segmented RB pair into several RE group. It is a figure which shows the example which divided | segmented RB pair into several RE group. It is a figure which shows the other example which arrange | positions and demodulates R-PDCCH / (R-) PDSCH. It is a figure which shows the other example which arrange | positions and demodulates R-PDCCH / (R-) PDSCH. It is a figure which shows the other example which arrange | positions and demodulates R-PDCCH / (R-) PDSCH. It is a figure which shows the other example which arrange | positions and demodulates R-PDCCH / (R-) PDSCH. It is a figure which shows the case where UL grant is transmitted only when a DL RA bit is set to 0. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the format of downlink control information (Downlink Control Information: DCI). It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the various method of alert | reporting the resource usage condition of a 2nd slot. It is a figure which shows the method of ordering the index of the physical downlink control channel (Relay Physical Downlink Control Channel: R-PDCCH) of a relay, and the example of resource allocation by it. FIG. 5 is a diagram illustrating a method for arranging indexes of physical downlink control channels of relays and resource allocation examples based thereon. FIG. 5 is a diagram illustrating a method for arranging indexes of physical downlink control channels of relays and resource allocation examples based thereon. FIG. 5 is a diagram illustrating a method for arranging indexes of physical downlink control channels of relays and resource allocation examples based thereon. It is a figure which shows the base station, relay, and terminal which can be applied to this invention.

  The accompanying drawings, which are included as part of the detailed description to assist in understanding the present invention, provide examples of the present invention and together with the detailed description, explain the technical idea of the present invention.

  The configuration, operation, and other features of the present invention will be readily understood from the embodiments of the present invention described below with reference to the accompanying drawings. Embodiments of the present invention can be used for various wireless access technologies such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, MC-FDMA. CDMA may be a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA is a global system for mobile communications (GSM (registered trademark)) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSME Evolution: Wireless technology such as EDGE). OFDMA may be a radio technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Evolved UTRA (E-UTRA), and so on. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project long term evolution (3GPP LTE) is part of Evolved UMTS (E-UMTS) using E-UTRA. LTE-Advanced (LTE-A) is an advanced version of 3GPP LTE.

  The following examples will be described with a focus on the case where the technical features of the present invention are applied to a 3GPP system, but these are examples and are not intended to limit the present invention.

  FIG. 1 illustrates the structure of a radio frame used in the 3GPP system.

Referring to FIG. 1, a radio frame has a length of 10 ms (307200 · T _s ) and is composed of ten equally sized subframes. Each subframe has a length of 1 ms and is composed of two slots. Each slot has a length of 0.5 ms (15360 · T _s ). T _s represents a sampling time, and is expressed as T _s = 1 / (15 kHz × 2048) = 3.2552 × 10 ⁻⁸ (about 33 ns). A slot includes a plurality of OFDM or SC-FDMA symbols in the time domain, and includes a plurality of resource blocks (RBs) in the frequency domain. In the LTE system, one resource block includes 12 subcarriers × 7 (6) OFDM or SC-FDMA symbols. A transmission time interval (TTI), which is a unit time for transmitting data, can be defined as one or more subframes. The structure of the radio frame described above is merely an example, and the number of subframes or subslots and the number of OFDM / SC-FDMA symbols in the radio frame may be variously changed.

  FIG. 2 illustrates a resource grid of a downlink slot.

  The downlink slot structure illustrated in FIG. 2 is similarly applied to the uplink slot structure. However, the uplink slot structure includes SC-FDMA symbols instead of OFDM symbols.

  FIG. 3 illustrates a structure of a downlink subframe used in the 3GPP system.

  Referring to FIG. 3, one or a plurality of OFDM symbols from the top of the subframe are used for the control region, and the remaining OFDM symbols are used for the data region. The size of the control area can be set independently for each subframe. The control region is used to transmit scheduling information and other L1 / L2 (layer1 / layer2) control information. The data area is used to transmit traffic. The control channel includes a physical control format indicator channel (Physical Control Format Indicator CHannel: PCFICH), a physical HARQ indicator channel (Physical Hybrid-automatic repeat request (ARQ) Indicator CHannel: PHICH), and a physical downlink control channel (Physical Downlink Control CHannel: PDCCH). The traffic channel includes a physical downlink shared channel (PDSCH).

  The PDCCH includes information related to resource allocation of a paging channel (PCH) and a downlink shared channel (DL-SCH), which are transmission channels, an uplink scheduling grant, and HARQ information. Etc. to each terminal or terminal group. A paging channel (Paging CHannel: PCH) and a downlink shared channel (Downlink-shared CHannel: DL-SCH) are transmitted through the PDSCH. Therefore, the base station and the terminal generally transmit and receive data through the PDSCH except for specific control information or specific service data. Control information transmitted through the PDCCH is referred to as downlink control information (DCI). DCI refers to uplink resource allocation information, downlink resource allocation information, an uplink transmission power control command to an arbitrary terminal group, and the like. A base station determines a PDCCH format based on DCI sent to a terminal, and adds a cyclic redundancy check bit (Cyclic Redundancy Check: CRC) to control information. In the CRC, a unique identifier (for example, a radio network temporary identifier (RNTI)) is masked according to the owner or use of the PDCCH.

  FIG. 4 illustrates an uplink subframe structure used in the 3GPP system.

  Referring to FIG. 4, a 1 ms long subframe 500, which is a basic unit of LTE uplink transmission, includes two 0.5 ms slots 501. Assuming the length of a normal cyclic prefix (CP), each slot is composed of seven symbols 502, and one symbol corresponds to one SC-FDMA symbol. A resource block (RB) 503 is a resource allocation unit corresponding to 12 subcarriers in the frequency domain and 1 slot in the time domain. The structure of the LTE uplink subframe is roughly divided into a data area 504 and a control area 505. The data area means communication resources used to transmit data such as voice and packets transmitted to each terminal, and includes a physical uplink shared channel (PUSCH). The control region refers to a communication resource used to transmit an uplink control signal, for example, a downlink channel quality report from each terminal, a reception ACK / NACK for the downlink signal, an uplink scheduling request, and the like. A link control channel (Physical Uplink Control CHannel: PUCCH) is included. A sounding reference signal (SRS) is transmitted through an SC-FDMA symbol positioned last on the time axis in one subframe. The SRSs of a plurality of terminals transmitted in the last SC-FDMA in the same subframe can be distinguished by the frequency position / sequence.

  FIG. 5 illustrates processing for transmitting a signal using the multi-antenna method.

  Referring to FIG. 5, the codeword is scrambled by the scramble module 301. The code word includes an encoded bit string corresponding to the transmission block. The scrambled codeword is input to the modulation mapper 302, and is modulated into complex symbols by the BPSK, QPSK, 16QAM, or 64QAM system according to the type of transmission signal and / or the channel state. The modulated complex symbol may be mapped to one or a plurality of layers by the layer mapper 303. The codeword-to-layer mapping can be different according to the transmission scheme. The layer-mapped signal may be multiplied by a predetermined precoding matrix selected according to the channel state by the precoding module 304 and assigned to each transmission antenna. Each antenna-specific transmission signal processed in this way is mapped to a time-frequency resource element used for transmission by the resource element mapper 305, and thereafter transmitted from each antenna via the OFDMA signal generator 306. Is possible.

  FIG. 6 illustrates a demodulation reference signal (DeModulation Reference Signal: DM RS) structure. The DM RS is a terminal-specific reference signal used for demodulating a signal of each layer when a signal is transmitted using a multi-antenna. DM RS is used for demodulation of PDSCH and R (Relay) -PDSCH. Since the LTE-A system considers up to 8 transmit antennas, a maximum of 8 layers and their respective DM RSs are required. For convenience, DM RSs for layers 0-7 are referred to as DM RSs (layers) 0-7, respectively.

  Referring to FIG. 6, in the DM RS, two or more layers share the same RE, and are multiplexed by a Code Division Multiplexing (CDM) scheme. Specifically, the DM RS for each layer is spread using a spreading code (for example, an orthogonal code such as a Walsh code or a DFT code) and then multiplexed on the same RE. For example, DM RSs for layers 0 and 1 share the same RE, but are spread using orthogonal codes on two REs of OFDM symbols 12 and 13, for example, with subcarrier 1 (k = 1). That is, in each slot, DM RSs for layers 0 and 1 are spread along the time axis using a spreading factor (SF) = 2 code and then multiplexed on the same RE. For example, the DM RS for layer 0 can be spread using [+1 +1], and the DM RS for layer 1 can be spread using [+1 -1]. Similarly, DM RSs for layers 2 and 3 are spread on the same RE using different orthogonal codes. The DM RSs for layers 4, 5, 6, and 7 are spread on the REs acquired by DM RSs 0 and 1 and 2 and 3 with codes orthogonal to the existing layers 0, 1, 2, and 3. The The code of SF = 2 is used for DM RS up to 4 layers, and the code of SF = 4 is used for DM RS when 5 or more layers are used. In LTE-A, the antenna ports for DM RS are {7, 8,..., N + 6} (n is the number of layers).

  Table 1 shows a spreading sequence for antenna ports 7 to 14 defined in LTE-A.

  From Table 1, it can be seen that the orthogonal codes for the antenna ports 7 to 10 have a structure in which an orthogonal code of length 2 is repeated. Therefore, as a result, up to four layers were used with a length 2 orthogonal code at the slot level, and when 5 or more layers were used, a length 4 orthogonal code was used at the subframe level. To be the same.

Hereinafter, resource block mapping will be described. A physical resource block (PRB) and a virtual resource block (VRB) are defined. The physical resource block is as illustrated in FIG.

The virtual resource block has the same size as the physical resource block. A local type virtual resource block (Localized VRB: LVRB) and a distributed type virtual resource block (Distributed VRB: DVRB) are defined. Regardless of the type of virtual resource block, a pair of resource blocks are allocated together by a single virtual resource block number (n _VRB ) across two slots in a subframe.

  FIG. 7 illustrates a method for mapping virtual resource blocks to physical resource blocks.

  Hereinafter, resource allocation defined in the existing LTE will be described with reference to the drawings. FIG. 8 to FIG. 10 are diagrams showing a control information format for type 0 resource allocation (Resource Allocation: RA), type 1 RA, and type 2 RA, and resource allocation examples based thereon.

  The terminal analyzes the resource allocation field based on the detected PDCCH DCI format. The resource allocation field in each PDCCH includes two parts: a resource allocation header field and actual resource block allocation information. PDCCH DCI formats 1, 2 and 2A for type 0 and type 1 resource allocation have the same format and are distinguished from each other by a single bit resource allocation header field present by the downlink system band. Specifically, type 0 RA is indicated by 0, and type 1 RA is indicated by 1. PDCCH DCI formats 1, 2 and 2A are used for Type 0 or Type 1 RA, while PDCCH DCI formats 1A, 1B, 1C and 1D are used for Type 2 RA. The PDCCH DCI format with Type 2 RA does not have a resource allocation header field.

  Referring to FIG. 8, in the type 0 RA, the resource block allocation information includes a bitmap indicating a resource block group (RBG) allocated to the terminal. An RBG is a set of consecutive PRBs. The size (P) of RBG depends on the system bandwidth as shown in Table 3.

Referring to FIG. 10, in the type 2 RA, the resource block allocation information indicates a set of LVRBs or DVRBs continuously allocated to the scheduled terminals. When signaling resource allocation in PDCCH DCI format 1A, 1B or 1D, a 1-bit flag indicates whether LVRB or DVRB is allocated (eg, 0 represents LVRB allocation, 1 is DVRB allocation) Represents). On the other hand, when signaling resource allocation in the PDCCH DCI format 1C, only DVRB is always allocated. The type 2 resource allocation field includes a resource indication value (RIV), and the RIV corresponds to a start resource block (RB _start ) and a length. The length represents the number of resource blocks allocated so as to be virtually contiguous.

  FIG. 11 illustrates a communication system including a relay (Relay or relay node (RN)). The relay expands the service area of the base station or is installed in the shadow area to facilitate the service. Referring to FIG. 11, the wireless communication system includes a base station, a relay, and a terminal. The terminal communicates with the base station or the relay. For convenience, a terminal that communicates with a base station is called a macro terminal (macro UE), and a terminal that communicates with a relay is called a relay terminal (relay UE). A communication link between the base station and the macro terminal is called a macro access link, and a communication link between the relay and the relay terminal is called a relay access link. A communication link between the base station and the relay is called a backhaul link.

  Relays can be classified into L1 (Layer 1) relays, L2 (Layer 2) relays, and L3 (Layer 3) relays according to the number of functions executed in multi-hop transmission. The simple features of each are as follows. The L1 relay normally has a repeater function, and simply amplifies a signal from the base station / terminal and transmits it to the terminal / base station. Since there is no decoding in the relay, there is an advantage that the transmission delay is short, but since there is no distinction between the signal and the noise, there is a disadvantage that the noise is amplified. In order to compensate for these drawbacks, an improved repeater (advanced repeater or smart repeater) having functions such as UL power control and self-interference cancellation may be used. The operation of the L2 relay can be expressed as decoding-and-forward, and user plane traffic can be transmitted to L2. Although there is an advantage that noise is not amplified, there is a disadvantage that a delay due to decoding increases. L3 relay, also called self-backhauling, can send IP packets to L3. Since it also has a radio resource control (RRC) function, it plays a role like a small base station.

  It can be said that the L1 and L2 relays correspond to a case where the relay is a part of a donor cell covered by the corresponding base station. If the relay is part of a donor cell, the relay cannot control its own cell and the terminal of that cell, and the relay cannot have its own cell ID. However, it is possible to have a relay ID that is an ID (Identity) of the relay. In such a case, some functions of radio resource management (RRM) are controlled by the base station of the donor cell, and a part of the RRM may be located in the relay. The L3 relay corresponds to a case where the relay can control its own cell. In such a case, the relay can manage one or a plurality of cells, and each cell managed by the relay can have a unique physical layer cell ID (unique physical-layer cell ID). It can have the same RRM mechanism as the base station, and for the terminal, there is no difference between connecting to a cell managed by a relay and connecting to a cell managed by a general base station.

  Relays are classified according to mobility as follows.

    -Fixed RN: permanently fixed and used to increase shadow area and cell coverage. A simple repeater function is also possible.

    -Nomadic RN: A relay that can be temporarily installed when a user suddenly increases, or can be moved arbitrarily within a building.

    -Mobile RN: A relay that can be mounted on public transportation such as buses and subways, and the mobility of the relay must be supported.

  The following classification is also possible according to the link between the relay and the network.

    In-band connection: In the donor cell, the network-to-relay link and the network-to-terminal link share the same frequency band.

    Out-band connection: The network-to-relay link and the network-to-terminal link use different frequency bands in the donor cell.

  Further, the following classification is possible depending on whether the terminal recognizes the presence of the relay.

    -Transparent relay: The terminal does not know that communication with the network is performed via the relay.

    -Non-transparent relay: The terminal knows that communication with the network takes place via the relay.

FIG. 12 shows an example in which backhaul transmission is performed using the MBSFN subframe. In in-band relay mode, the base station-relay link (ie, backhaul link) operates in the same frequency band as the relay-terminal link (ie, relay access link). When a relay transmits a signal to a terminal while receiving a signal from a base station or vice versa, the relay transmitter and receiver induce interference with each other, so that the relay transmits and transmits simultaneously. There may be restrictions on receiving. Therefore, the backhaul link and the relay access link are partitioned by the TDM method. LTE-A sets up a backhaul link in the MBSFN subframe in order to support the measurement operation of legacy LTE terminals existing in the relay zone (fake MBSFN method). When an arbitrary subframe is signaled as an MBSFN subframe, the terminal receives only the control region (ctrl) of the subframe, so the relay configures the backhaul link using the data region of the subframe. can do. As an example, a relay PDCCH (Relay PDCCH: R-PDCCH) is transmitted using a specific resource region in the last OFDM symbol from the third OFDM symbol of the MBSFN subframe.
Example

  FIG. 13 and FIG. 14 are diagrams showing arbitrarily divided resources configured by frequency-time. FIG. 13 shows the case of a single antenna port, and FIG. 14 shows the case of a multi-antenna port. The drawing may mean a part of a downlink subframe.

  In FIG. 13, the size of the frequency-time domain represented by XY can be variously configured. In the LTE system, each of the resource region X-1 (X = 1, 2, 3) can be composed of 12 subcarriers in the frequency domain and 4 OFDM symbols in the time domain. Each of the resource region X-2 (X = 1, 2, 3) can be composed of 12 subcarriers in the frequency domain and 7 OFDM symbols in the time domain. The number of symbols may vary depending on the length of the cyclic prefix. The number of symbols and the number of subcarriers described above may have different values depending on the system. In other words, the resource area X-1 can mean a part of the first slot, and the resource area X-2 can mean the second slot. Such a resource configuration typically appears in the backhaul link subframe between the base station and the relay. In this case, FIG. 13 may correspond to the remaining part other than the control information area in the MBSFN subframe of FIG.

  FIG. 13 shows a resource block (RB) and a resource block group (RBG) in order to represent the size of the resource in the frequency domain. RB is originally a resource defined in slot units as shown in FIG. Therefore, each XY corresponds to one resource block, and [X-1, X-2] corresponds to a resource block pair. Unless otherwise stated, RB may refer to [X-1] or [X-2] or [X-1, X-2] depending on the context. The RBG is composed of one or a plurality of continuous RBs. Although the number of RBs constituting the RBG is three in FIG. 13, this is merely an example, and the number of RBs constituting the RBG may be changed according to the system band as shown in Table 3. Here, RB means PRB or VRB.

  In FIG. 14, the size of the frequency domain and the time domain of the resource domain represented as Px-yy (x, y = 0, 1, 2, 3,...) Can be variously configured. The basic resource configuration is as described with reference to FIG. In the drawing, Pn (n = 0, 1, 2, 3,...) Means a port or layer used in a multi-layer transmission system (for example, a MIMO system). A port or layer means a distinguishable resource area where different information can be transmitted. The meaning of ports or layers may be analyzed separately for each system. In the case of 3GPP LTE system as an example, if P0-12 is one RB, the frequency domain can be composed of 12 subcarriers, the time domain can be composed of 7 OFDM symbols, and 1 RBG (for example, If RBG = 4), the size of the frequency domain can be increased by a factor of four. The Px-y1 region is configured by the same or a smaller number of REs as the Px-y2 region. For example, if the Px-y1 resource region is RB, it can be configured with 12 subcarriers and 4 OFDM symbols, and if it is RBG, the frequency region is increased by a multiple of RBG units. Px-y1 may mean the first slot or part thereof, and Px-y2 may mean the second slot or part thereof. The number of symbols may vary depending on the length of the cyclic prefix. The number of symbols and the number of subcarriers described above may have other values depending on the system.

  Hereinafter, it will be proposed how to allocate and transmit control information and data in the resource configuration in the form shown in FIGS. Unless otherwise specified, the description will focus on the case of a single antenna port, and the display of the resource area will also follow the method of FIG. This is for convenience of explanation, and it will be obvious to those skilled in the art that the description for a single antenna port is also applicable to a multi-antenna port.

  Control information (for example, R-PDCCH) used in the link between the base station and the relay is preferably transmitted on a predetermined specific resource region. According to an example of the present invention, a specific resource region (referred to as R-PDCCH search space) to which control information can be transmitted when LTE type 0 resource allocation (RA) is used is allocated. It can be limited to the Kth RB of the RBG. Here, K represents an integer smaller than the number of RBs constituting the RBG. In this case, the K-th RB of all assigned RBGs may transmit R-PDCCH. K may be the first RB of the RBG or the last RB. The type 1 and 2 RA can also share the concept of RBG, and a specific RB of the RBG can be used as a resource area for R-PDCCH transmission by the same logic.

In addition, when the R-PDCCH search space is specified as any one subset of the RBG set, a method is proposed in which the RBs for the R-PDCCH search space are positioned apart by the square of P in the RBG set. . Here, P is the number of RBs in the RBG. For example, assuming 32 RBs, 11 RBGs can be defined, and one RBG can be composed of 3 RBs (P = 3). Therefore, the R-PDCCH search space is preferably arranged at intervals of 3 ² = 9 RBs. The above-described example is an example in the case of using one RBG subset, and when there are two RBG subsets, it means that the interval between RBs is the square of P in the corresponding subset. The spacing between the subsets may vary depending on how many subsets are selected.

R-PDCCH / (R-) PDSCH allocation and demodulation control information is transmitted through R-PDCCH, and data is transmitted through (R-) PDSCH. R-PDCCH is roughly classified into two categories. One category is DL grant (Downlink Grant: DG), and the other category is UL grant (Uplink Grant: UG). The DL grant includes information on R / PDSCH time / frequency / space resources corresponding to data to be received by the relay and information for decoding (that is, scheduling information). The UL grant includes information on time / frequency / space resources of the R-PUSCH corresponding to data to be transmitted by the relay in the uplink and information for decoding (that is, scheduling information). Hereinafter, a method for arranging a DL / UL grant in a resource area of a backhaul subframe and demodulating the DL / UL grant will be described with reference to the drawings.

  FIG. 15 shows an example in which R-PDCCH / (R-) PDSCH is arranged and demodulated. In this example, it is assumed that resources for (R-) PDSCH are allocated using LTE type 0 RA (RBG unit allocation). However, this is an example, and this example is applied in the same / similar manner when using LTE type 1 RA (RB unit allocation). In addition, this figure illustrates the case where the RBG in which the DL grant exists is assigned to the corresponding relay. However, this is an example, and even if the RBG in which the DL grant exists is not assigned to the corresponding relay. Good.

  FIG. 15 shows that when the DL grant of RN # 1 exists in the resource region 1-1, (a) data ((R-) PDSCH) exists in the resource region 1-2, or (b) UL grant Or (c) a UL grant for another relay exists.

  In FIG. 15, it can be known from RA information (for example, RBG or RB allocation information) which information of (a) to (c) exists in the resource area 1-2. For example, if both RBGs are assigned to RN # 1, RN # 1 analyzes the RA information of the DL grant, and resource region 1-2 corresponds to either (a) or (b). Can be determined. Specifically, when data exists in the RB or RBG in which the first R-PDCCH (for example, DL grant) for itself is detected in the resource region X-1, the RN # 1 is in the RB or RBG. It can be assumed that the resources other than that occupied by the first R-PDCCH have their own data. Therefore, when the RA information indicates that data exists in the RB or RBG, the RN # 1 can determine that no other R-PDCCH other than the detected DL grant exists in the RB or RBG. That is, the relay can determine that the resource area 1-2 corresponds to (a). On the other hand, when the RA information indicates that there is no data in the RB or RBG, the relay determines that the second R-PDCCH exists as shown in (b) or (c), and appropriately starts the data start point. (For example, the resource area 2-1) can be searched. At this time, the base station and the relay can assume that the size of the second R-PDCCH is constant. In case (c), it can be seen that the second R-PDCCH is not a UL grant for RN # 1 by attempting RN ID based CRC detection. On the other hand, even if RA information is used to distinguish (a), (b) or (c), the RBG where the DL grant exists is always a resource allocated for the data of RN # 1. , Can be implied in advance.

  FIG. 15 shows a case where the DL grant exists in the entire resource region X-1 (for example, 1-1), but this is an example, and the DL grant is only in a part of the resource region 1-1. Even if it exists, the above method can be applied equally. FIG. 15 shows a case where a DL grant is present in the resource region X-1, but a UL grant may be present in the resource region X-1 instead of the DL grant. In this case, the relay includes a process of first decoding the UL grant instead of the DL grant. FIG. 15 shows that the second R-PDCCH is a UL grant, but this is an example, and the second R-PDCCH may be a DL grant.

  16 and 17 show another example in which R-PDCCH / (R-) PDCCH is arranged and demodulated. In this example, it is assumed that resources for (R-) PDSCH are allocated using LTE type 0 RA (RBG unit allocation). However, this is an example, and this example is applied in the same / similar manner when using LTE type 1 RA (RB unit allocation). In addition, this figure illustrates the case where the RBG in which the DL grant exists is assigned to the corresponding relay. However, this is an example, and even if the RBG in which the DL grant exists is not assigned to the corresponding relay. Good.

  FIGS. 16 and 17 show that when the DL grant of RN # 1 exists in the resource area 1-1 / 1-2, (a) data ((R-) PDSCH) in the resource area 2-1 / 2-2 (B) There is a UL grant for RN # 1 in the resource area 2-1 (FIG. 16), (c) RN in the resource area 2-1 / 2-2 The case where the UL grant for # 1 exists (FIG. 17) is illustrated.

  In this case, RN # 1 can distinguish (a), (b), or (c) by performing blind decoding. This is preferable when there is data or control information of RN # 1 in the resource area 2-X.

  Also, RN # 1 can distinguish (a), (b), or (c) using DL grant RA information (for example, RBG allocation bits). For example, the RN # 1 uses the RA information to distinguish whether the data in the resource area 2-1 is the data of the RN # 1 or the UL grant allocated exclusively to the resource area 2-1. (Ie (a) or (b)) (Case A). Also, RN # 1 is assigned only to resource area 2-1 / 2-2 using RA information, whether the data in resource area 2-1 / 2-2 is the data of RN # 1 It can be distinguished whether it is a UL grant (ie (a) or (c)) (Case B). Therefore, the base station-relay operation must be set to either case A or case B. That is, RN # 1 can distinguish (a) or (b), or (a) or (c) using RA information (for example, RBG allocation bits). It is necessary to set in advance which of the two uses the RBG allocation bit. For example, it must be determined in advance whether the UL grant is assumed to be limited to the resource area 2-1 or to the resource area 2-1 / 2-2.

  Further, when the DL grant of RN # 1 exists in the resource area 1-1 / 1-2, (a) RN # 1 data (not shown), (b) in the resource area 2-1 / 2-2 ) A DL or UL grant of another RN may exist in the resource area 2-1 (FIG. 16), and a DL or UL grant of another RN may exist in the resource area 2-1 / 2-2 (FIG. 17). ). In this case, it is possible to distinguish (a) or (b) using the RBG allocation bits, or to distinguish (a) or (c). It is necessary to set in advance which of the two uses the RBG allocation bit.

  If only the DL / UL grant size that is the same as the DL grant size is present in the above-described method, the RBG allocation bit indicates whether the value existing in the resource area 2-1 or 2-1 / 2-2 is data, or control information. The DL / UL grant size (i.e., the resource region 2-1 or 2-1 / 2-2) can be determined by the detected DL grant size.

  The above-described method is equally applied when the DL grant extends over the resource regions 1-1, 1-2, and 1-3. Further, the above-described method is equally applied to the case where all or part of the UL grant exists in the resource areas 1-1, 2-1, 3-1 instead of the DL grant. In this case, in the above method, the relay first blind-decodes the UL grant instead of the DL grant.

Demodulation method using the same DM RS port When the grant (for example, DL grant) for RN # 1 is successfully demodulated in the resource region 1-1, another DM RS corresponding to the successful DM RS port is used. We propose a method of demodulating the DL transmission signal in the resource area, and otherwise demodulating the DL transmission signal in another resource area using a DM RS different from the DM RS port used in the resource area 1-1. For example, when the DL grant of the RN # 1 is successfully demodulated in the resource region 1-1, the DL transmission signal (eg, UL grant) of the resource region 1-2 is transmitted using the DM RS corresponding to the successful DM RS port. Otherwise, the DL transmission signal (for example, UL grant) in the resource region 1-2 can be demodulated using a DM RS different from the DM RS port used in the resource region 1-1. Specifically, if the resource region 1-1 is successfully demodulated at the DM RS port 0, the DL transmission signal (eg, UL grant) of the resource region 1-2 is also transmitted to the DM of the same DM RS port 0. Demodulate using RS, otherwise (if unsuccessful), it can be demodulated using DM RS port 1 DM RS.

In the TDM + FDM method, the RB pair is filled with the UL grant (or DL grant), and if the UL grant of RN # 1 exists in the resource region 1-1 (that is, if the DL grant of RN # 1 does not exist), the resource There is a case where the area 1-2 is not used. In order to solve this, a method for filling the resource region 1-2 with the UL grant of the relay in which only the UL grant exists is proposed. If there are a large number of relays in which only the UL grant exists, waste of resources can be minimized by satisfying all of X-1 and X-2 with the UL grant.

  Similarly, when only DL grant exists, it is proposed to operate by assigning DL grant to both resource region 1-1 and resource region 1-2.

RS Port Assignment Method FIGS. 18 and 19 show an example in which an RB pair is divided into a plurality of RE groups. In the examples of FIGS. 18 and 19, it is assumed that the whole or a part of the symbol period of the subframe can be defined at the start and end portions of the resource region.

  FIG. 18 illustrates a case where one RB pair is divided into two RE groups (Xa, Xb). In FIG. 18, the sizes of Xa and Xb (X = 1, 2, 3) may be the same or different. Here, the resource regions 1-a and 1-b are used to transmit the DL grant and UL grant of RN # 1, respectively, and the resource region 2-a transmits the DL grant of RN # 2 and resource region 2- It is assumed that b and 3-a are used to transmit the DL grant of RN # 3, and the resource region 3-b is used to transmit the UL grant of RN # 3. In this case, the resource areas 1-a and 1-b are configured to demodulate based on one DM RS port, and the resource areas 2-a and 2-b demodulate based on different DM RS ports. It is proposed that the resource areas 3-a and 3-b are configured to demodulate based on the same DM RS port. By doing this, DL / UL grants transmitted to the same RN can obtain better performance using one same DM RS port, and for DL / UL grants transmitted to different RNs, A DM RS port suitable for each RN can be assigned.

  FIG. 19 illustrates a case where one RB pair is divided into three RE groups (Xa, Xb, Xc). FIG. 19 is the same as the description in FIG. 18 except that the number of RE groups is changed. Refer to FIG. 18 for the detailed description.

The R-PDCCH mapping and detection relay at a high aggregation level may change the R-PDCCH R-CCE aggregation level (eg, 1, 2, 4, 8,...) Depending on the channel environment. This is similar to LTE PDCCH CCE aggregation. For convenience, R-CCE is defined to distinguish CCEs for relay, and R-CCE is mixed with CCE in the following description. Assume that the DL grant of R-PDCCH exists over three RBs as shown in FIG. 20, and the UL grant is transmitted over the second slot of two RB pairs. In this case, if the DL grant is blind-decoded and an R-CCE aggregation as shown in FIG. 20 is found, the relay has a UL grant or data in the second slot. I do n’t know.

Of course, a method similar to the method described above may be applied. That is, it is possible to notify whether or not there is a UL grant in the second slot with the RBG allocation bit. Preferably, it can be assumed that the RBG in which the DL grant exists is assigned to the corresponding relay. Therefore, when there is a DL grant in the first slot, the resource allocation bit for the RBG can inform that the R-PDSCH or UL grant is in the second slot. The following cases are possible:
(A) R-PDSCH exists in the second slot, or (b) UL grant for the same relay or UL grant for another relay exists in the second slot. UL grants of other RNs can be confirmed by CRC check using RN ID.

  The problem here is in which RB pair the UL grant is present. For example, the number of RB pairs in which a UL grant exists may change depending on the R-CCE aggregation level.

  The number / position of RB pairs in which the UL grant exists can be known by creating a simple relationship between the DL grant size and the UL grant size. This is illustrated with reference to FIGS.

  Referring to FIG. 21, the UL grant can always exist in the RB pair in which the DL grant exists. Thus, if a DL grant exists over two RB pairs, a UL grant can exist in two RB pairs as well. Thus, if the DL grant is successfully detected, the relay knows where the UL grant is. Therefore, the UL grant aggregation level can be set higher than the DL grant aggregation level. Alternatively, it can be defined in advance that there is a difference of N_level times between the DL grant aggregation level and the UL grant aggregation level.

  As an example, it can be defined that there is one R-CCE in the first slot of the RB pair and two R-CCEs in the second slot. In this case, the R-CCE of the first slot and the R-CCE of the second slot are different in size. According to this example, the DL grant aggregation level x2 can be defined in advance as UL grant aggregation level. Referring to FIG. 21, the DL grant aggregation level for RN # 1 is 2, and the aggregation level for UL grant is 4. Similarly, the DL grant aggregation level for RN # 2 is 3, and the aggregation level for UL grant is 6.

  As another example, the R-CCE size can be defined in units of slots. That is, it can be defined that one R-CCE exists in the first slot of the RB pair and one R-CCE exists in the second slot. In this case, the R-CCE of the first slot and the R-CCE of the second slot are different in size. According to this example, it can be defined in advance that DL grant aggregation level = UL grant aggregation level. Referring to FIG. 21, in the case of RN # 1, the aggregation level of DL grant = the aggregation level for UL grant = 2. Similarly, in the case of RN # 2, the DL grant aggregation level = UL grant aggregation level = 3.

  Referring to FIG. 22, a case where the R-CCE size is set to one and DL grant aggregation level = UL grant aggregation level is illustrated. For example, the R-CCE size may be 32 REs. In this case, since the resource area of the second slot is larger, it can be arranged as shown in FIG. In the case of RN # 2, only some resources are used for UL grant transmission in the second slot of the second RB pair. In this case, the empty space in the second slot may be used for data transmission (FIG. 22 (a)), and may not be used for data transmission (FIG. 22 (b)).

  As another method, the number of RBs occupied by the UL grant may be limited. As an example, as in the case of RN # 1 in FIG. 22, the UL grant can always be limited to be transmitted in the second slot of one RB pair. Such a restriction may be fixed as a standard, or may be transmitted from the base station to the RN through an upper layer signal. If there is such a restriction, the RN can easily grasp the position of the region occupied by the UL grant through the above-described reanalysis of the RA information, and thereby the position of the data signal can be grasped.

  In the above description, the RBG allocation bit can be reanalyzed and used to distinguish UL grant or data (R-PDSCH) on the assumption that the RBG is used only for the RN. This is because of this. However, when RBG is used as the meaning of the original value of RBG, another signal can be provided. Such a signal can be present on the R-PDCCH. Further, whether to use another signal or to reanalyze the RBG may be set in advance, or may be configured by signaling in a quasi-static method.

  On the other hand, if the UL grant is indicated in the above method and decoding of the UL grant fails, the data (including the UL grant) in the corresponding slot is retransmitted through HARQ. Data may be combined. In this case, since a serious error may occur in data that is HARQ combined by the UL grant, previous data that may include the UL grant may not be used in the HARQ combining process.

  FIG. 23 shows a scheme in which even when only the UL grant exists, the DL grant is arranged in the first slot, and the DL grant notifies the second slot that the UL grant exists.

  Referring to FIG. 23, the base station can perform UL grant even when there is no downlink data (for example, ((R-) PDSCH) to be transmitted to the relay (that is, UL grant only case). Null DL grant (or dummy DL grant) can be sent to inform the relay that is present in the second slot of the same RB pair. Because the blind decoding for the UL grant can be omitted regardless of the presence or absence of downlink data for the relay, the complexity of the relay blind decoding is reduced. In situations where the UL grant is also sent but there is no actual downlink data for the relay, the data corresponding to the DL grant (Ie, a null DL grant), so the null DL grant can indicate that all downlink transmission blocks or codewords are disabled. The DL grant may indicate that the downlink transmission block size (TBS) is TBS = 0 or TBS <K (eg, 4 RB), and the null DL grant Any specific field in the null DL grant can be set to “0” or “1.” When a null DL grant is detected, the relay It is analyzed that there is no data transmission corresponding to the null DL grant, and the second slot from the null DL grant is analyzed. The presence of the UL grant is understood that.

A method of notifying the usage status of the second slot (for example, using RA bit)
Hereinafter, using the bits (or similar information) of the DCI resource allocation (Resource Allocation: RA) field, the presence / absence of the UL grant is indicated, or the presence / absence of the (R-) PDSCH is indicated. A method for accurately performing PDSCH data decoding will be described. For convenience, the resource allocation related technology used in the description follows the LTE technology. The RA bit indicates whether the corresponding RB or RBG is allocated for PDSCH transmission. When the RA bit = 0, the corresponding RB or RBG is not allocated for (R-) PDSCH transmission, and when the RA bit = 1, the corresponding RB or RBG is allocated for R-PDSCH transmission. Assume that The meaning of the RA bit may be analyzed in reverse. The meaning of the RA bit may differ depending on the DL grant and UL grant.

  DL grant and UL grant can be implemented to exist in RBs of different slots. For example, the DL grant may exist in the RB of the first slot, and the UL grant may exist in the RB of the second slot. In this case, the resource area for DL data and the area for UL grant coexist. The resource in which DL data is actually transmitted is indicated by the DL grant RA, and the resource in which the UL grant is actually transmitted is confirmed by blind decoding. Therefore, when the UL grant is detected in the resource area to which DL data is allocated, the relay receives / decodes DL data from the remaining resources other than the resource in which the UL grant is detected (ie, rate matching). I do). For this reason, non-detection or false detection of UL grants can affect DL data decoding, which is undesirable.

To overcome this, the following restrictions can be applied to base station-relay communication.
-The relay can assume / assum no UL grant on RB or RBG with DL resource allocation (RA) bit set to 1. That is, the relay can assume that UL grants can only be transmitted on RBs or RBGs whose DL resource allocation bits are zero. In this example, some resources may be used for data transmission in the RBG in which the DL resource allocation bit is 0.
-The above limitation is that DL data (i.e. (R) is also detected if the relay fails to detect UL grant (i.e. non-detection case) or false detection (i.e. false alarm case). -Accurate rate matching can be guaranteed when decoding (PDSCH).
-Therefore, the base station does not transmit UL grant on RB or RBG with DL resource allocation bit set to 1. For example, in the case of type 0 resource allocation, the base station does not transmit the UL grant on the RBG to which DL data for relay is allocated, except for the RBG in which both the DL grant and the UL grant exist.

  FIG. 24 illustrates a case where the UL grant is transmitted only when the DL RA bit is set to 0. For convenience, this example is illustrated using type 0 resource allocation for existing LTE. In this example, RA = 1 means that the corresponding RBG has been allocated for DL data transmission by ordinary RA analysis. However, RA = 0 can have a different meaning than normal RA analysis. In this example, it is assumed that a DL grant search space and a UL grant search space exist.

  Referring to FIG. 24, if the DL grant is successfully detected and the RA bit is “0”, for example, the UL grant is used, and the RA bit is “0” in the UL grant search space (UL SS). It can be designed to exist in either RB or RBG. Although the UL grant search space is configured regardless of the RA bit, the base station scheduler can intentionally make the UL grant exist only when the RA bit is “0”. That is, RA bit = 0 means an RBG capable of UL grant transmission, and UL grant transmission can be limited to resources that satisfy both UL SS and RA bit = 0. In this case, RA bit = 0 may be understood to indicate a partial subset in the R-PDCCH search space. Therefore, when the relay detects the DL grant, the relay can limit the UL grant search position to resources for which RA bit = 0 is set in the UL SS. Thereby, unnecessary erroneous detection of UL grant can be prevented. That is, RB or RBG with RA bit = 1 can be excluded from the search area for UL grant.

  Therefore, if the RA bit = 1, the relay assumes that UL grant is never transmitted in the RB or RBG. On the other hand, if the RA bit = 0, the relay assumes that the UL grant can be transmitted in the RB or RBG. Therefore, the base station transmits the UL grant only in RB or RBG with RA bit = 0. If the relay does not know the presence / location of the UL grant, it performs blind decoding, and if it knows the location of the UL grant, it can decode the UL grant at the specified location. According to the analysis of RA bit = 0 described above, the search space for UL grant (UL SS) can be dynamically limited (ie, assigned) using DL RA, so that the blind for UL grant Decoding times can be reduced.

  On the other hand, in the above description, the analysis of RA bit = 0 is described as a resource capable of transmitting UL grant. However, this is only an example, and RA bit = 0 may mean an RB or RBG in which a UL grant is actually transmitted in the UL SS. In this case, the analysis of RA bit = 0 can be limited to a specific RB (pair) or RBG. For example, analysis of RA bit = 0 is limited to RB (pair) or RBG in which DL grant exists.

  On the other hand, when considering data transmission, the analysis of RA = 0 can further include the following cases. As an example, an RBG with RA = 0 may include data transmission when a DL grant or any R-PDCCH exists in the RBG ((a) to (b)). As another example, RBG with RA = 0 may not transmit data regardless of the presence or absence of R-PDCCH ((c) to (d)).

  In FIG. 24, a dotted line indicates a case where type 1 resource allocation is used. In the type 1 resource allocation, the analysis of the RA bit is applied in units of RBs.

  In the following description, it is assumed that when the aggregation level of DL and UL grants is increased, R-PDCCH is extended and allocated to adjacent VRBs so as to be contiguous sequentially (non-interleaving). In this case, the R-PDCCH is not allocated in a non-contiguous manner. The actual PRB mapping may be different. The following description assumes that RA information in the DL grant conforms to LTE type 0, but the present invention is not limited to a specific type of RA information in this DL grant.

  FIG. 25 shows a method of notifying the resource allocation state of the second slot (for example, the presence or absence of UL grant) according to the present invention. FIG. 25 illustrates a case where RBG = 3RBs, 1 CCE DL grant, and 1 CCE UL grant. For convenience, one RBG having a DL grant is shown in the RBG set allocated by the DL RA. When interleaving is applied, DL grants can exist in multiple RBs or RBGs.

  Referring to FIG. 25, when transmitting 1 CCE DL grant, a method for notifying whether or not a UL grant exists in the resource area of the next slot is an existing RA bit (referred to as an RB indicator or an RBG indicator). It becomes possible by reanalyzing. For example, when the RA bit is 0, there may be a UL grant in the next slot of the RB pair where the DL grant exists in the RBG, and the R-PDSCH is allocated from the next RB pair. I can inform you. On the other hand, when the RA bit = 1, there is no UL grant in the next slot of the RB pair in which the DL grant exists in the RBG, and the R-PDSCH satisfies the resource area or the R- It may mean that PDSCH is not present. Presence / absence of R-PDSCH is set in advance as illustrated with reference to FIG. The RA bit analysis illustrated in FIG. 25 can be limited to RBs (pairs) or RBGs with DL grants.

  On the other hand, in the existing LTE, the DCI formats 0 and 1A have the same size and are distinguished using a 1-bit type instruction field. Therefore, if the DL grant and the UL grant are configured in independent spaces, the field for distinguishing the DL / UL grant is virtually meaningless. Therefore, although not shown, as another example, a type indication field for distinguishing between DCI formats 0 and 1A can be used for the applications mentioned above. For example, the type indication field may indicate presence / absence of UL grant or presence / position / placement of UL grant (eg, second slot of RB pair in which DL grant exists, 1 CCE). In this example, the type indication field can be used in addition to or independently of the existing RA bits.

  On the other hand, since the resource area of the second slot in the RB pair is larger than the resource area of the first slot, the number of CCEs included in the RB of each slot may be defined differently. For example, the RB of the first slot may be composed of one CCE, and the RB of the second slot may be composed of two CCEs. In this case, the UL grant can occupy only one of the two CCEs in the second slot. Also, the UL grant may be predetermined or signaled so as to always fill the resource area of the second slot (2CCE). Since it is very easy in terms of signaling to extend the UL grant CCE aggregation level in the form of 2, 4, and 6 levels, it is preferable to implement it in this way.

  FIG. 26A to FIG. 26C illustrate UL grant transmission according to the DL grant CCE aggregation level. 26A to 26C illustrate cases where the DL grant CCE aggregation levels are 1, 2, and 3, respectively. This figure shows a case where RBG = 3 RBs, but the number of REs constituting the RBG is not limited to this. For convenience, one RBG having a DL grant is shown in the RBG set allocated by the DL RA. When interleaving is applied, DL grants can exist in multiple RBs or RBGs.

  Referring to FIG. 26A, when 1 CCE DL grant is detected by blind decoding (BD), how the UL grant is in the second slot / resource region of the RB pair in which the DL grant is detected. It is very important to know what is arranged in. If the UL grant is decoded but fails, if this part is erroneously recognized as data and decoded, this may lead to an (R-) PDSCH decoding error. Therefore, it is preferable in terms of error case handling to know the UL grant position accurately. When the 1-CCE DL grant is detected in the first resource area, the UL resource or the (R-) PDSCH (including a free space) is notified in the second resource area, as described above, the RA bit ( RB indicator) or an RA bit for RBG (RBG indicator) can be used. Since only two cases need to be indicated, 1-bit information is sufficient.

  Referring to FIG. 26B, when 2-CCE DL grant is detected, the number of cases where UL grant and R-PDSCH are arranged in the second resource region of the corresponding RB pair is large, but the above assumption is applied. Then, as shown in the figure, it can be limited to three cases. Therefore, an instruction with 2 bits is required instead of 1 bit. Each case can be instructed by using an additional 1 bit for 1 bit of the RBG indication in FIG. 26A. One additional bit can be obtained from the DCI format. For example, in the DCI field, the size of the field that can be limited by the backhaul can be reduced, and the remaining bits can be used. Specifically, when used for backhaul, a method of using bits remaining with the length (width) of existing RA information slightly shortened is also possible. Of the fields defined additionally in the LTE-A DCI format, bits of fields that are not important or less important in the backhaul can be borrowed. For example, although the CIF field is composed of 3 bits, the maximum number of carriers in LTE-A is 5, and the number of carriers actually used may be smaller than that. Therefore, one bit or a plurality of states can be borrowed from the CIF field. A combination of RRC signaling and RA bits can also be used. Specifically, a part of the number of cases is limited by RRC signaling, and any one of the numbers remaining in the RA bit can be indicated. For example, UL grant transmission cases can be limited to (a) and (c) by RRC signaling, and (a) or (c) can be indicated by RA bits. The contents described above apply to all the drawings in common thereafter.

Referring to FIG. 26C, when 3-CCE DL grant is detected, the number of cases where UL grant and R-PDSCH are arranged in the second resource region of the corresponding RB pair is large, but the above assumption is applied. Then, as shown in the figure, it can be limited to four cases. Therefore, as illustrated in FIG. 26B, all cases can be indicated by 1 bit + 1 bit = 2 bits. Alternatively, a method in which 3-CCE DL grant allocation is not performed from the beginning is also possible. The DL grant BD complexity can be reduced by limiting the CCE aggregation level to 2 ⁿ (n = 0, 1, 2,...). For example, the relay can only perform BD for 1, 2, 4 CCE DL grants.

  27A to 27D illustrate UL grant transmission using the DL grant CCE aggregation level when the RBG is configured with four RBs. FIGS. 27A to 27D illustrate cases where the DL grant CCE aggregation levels are 1, 2, 3, and 4, respectively. For convenience, one RBG having a DL grant is shown in the RBG set allocated by the DL RA. When interleaving is applied, DL grants can exist in multiple RBs or RBGs. Since the basic matters are the same as those in FIGS. 27A to 27C, refer to FIGS. 27A to 27C for the detailed matters.

  Referring to FIG. 27A, when one CCE DL grant is detected, two transmission cases are possible, and all two cases can be indicated by the RA bit (one bit) for the corresponding RBG. Referring to FIG. 27B, when a 2CCE DL grant is detected, three transmission cases are possible, so an instruction with 2 bits is necessary. As described with reference to FIG. 26B, three cases can be indicated by using an additional 1 bit for the RA bit (1 bit) for the RBG. One additional bit can be obtained from the DCI format. For example, the remaining RA information can be used with the bit remaining slightly shorter. It is also possible to borrow one bit or multiple states from the CIF field. A combination of RRC signaling and RA bits can also be used. In this case, the number of cases is limited by RRC signaling, and any one of the numbers remaining in the RA bit can be indicated.

  Referring to FIG. 27C, four transmission cases are possible when a 3-CCE DL grant is detected. Therefore, all possible cases can be instructed by a 2-bit instruction. Further, similarly to RBG = 3RBs in FIG. 26C, the case of 3-CCE DL grant can be excluded from the beginning. Referring to FIG. 27D, five transmission cases are possible when a 4-CCE DL grant is detected. Therefore, it is not possible to indicate all cases with 2 bits. However, additional assumptions can be made here. For example, in FIG. 27D, the 3-CCE UL grant (c) having an odd CCE aggregation level may not be used. In FIG. 27D, the 4-CCE UL grant may not be used. Since there are more resources in the second slot than in the first slot, it is possible to set the CCE aggregation level of the UL grant to be lower than the CCE aggregation level of the DL grant. In this way, by excluding one or a plurality of cases (a) to (d), all cases can be indicated by a 2-bit instruction.

  In the above case, all cases can be indicated with 2 bits by limiting the UL grant aggregation level. For example, the UL grant aggregation level can be limited to 1, 2, or 1, 2, 4. In particular, since the second resource region in which the UL grant is located is large, it is meaningful to assume that only 1 RB (for example, 1-CCE) or 2 RB (2-CCE) is used. Since the CCE of the second slot includes approximately twice as many REs as the CCE of the first slot, even if the UL grant aggregation level is limited to 1 or 2, the UL grant is substantially at aggregation level 2 Or a code rate corresponding to 4 DL grants may be indicated. Of course, when the boundary between the first resource region and the second resource region is adjusted and the resource regions are the same, the method of setting the UL grant aggregation level to 1, 2, and 4 is advantageous. In this case, it is preferable to limit the DL grant aggregation level to 1, 2, and 4.

  The CCE sizes may be defined identically, and may be defined for several limited size CCEs. The CCE described above conceptually shows a unit for allocating DL / UL grant as shown in each figure.

  In the above description, the RA bit analysis is performed differently from the existing one, and the description has been focused on the example of providing information on the usage state (for example, the presence / location of the UL grant) of the second slot. However, instead of analyzing the RA bit differently from the existing one, it can be considered to add a new bit field in the DCI to provide information on the usage status of the second slot. The new bit field may be a part of a bit field defined for other existing purposes (for example, 2 bits), or may be a dedicated bit field newly defined for the corresponding purpose.

  FIG. 28 shows an example in which a field in the DCI format is used to provide information regarding the usage status (for example, presence / location of UL grant) of the second slot. The method of FIG. 28 may be used together with the analysis of the RA bit or may be used separately.

  Referring to FIG. 28, DCI format 0 / 1A includes a 1-bit flag field (0 / 1A) for distinguishing between them. DCI format 0 is for the UL grant, and DCI format 1A is for the DL grant. As illustrated in the previous drawing, when the resources for transmitting DL grant and UL grant are distinguished in the time domain, or when the UL grant size is different from the DL grant size, the DCI format 0 / 1A is distinguished. No flag field is required. Therefore, a flag field for distinguishing DCI format 0 / 1A can be used to provide information on the usage status of the second slot (eg, presence / location of UL grant). The DCI format 1A / 1B / 1D includes an L / DVRB indication field (L / DVRB). If in relay, DVRB is always disabled (OFF) and limited to support only LVRB, the L / DVRB indication field is set to the second slot usage status (eg UL grant). Can be used to provide information on DCI format 1/2 / 2A / 2B includes a resource allocation header field (RA Hdr.) For indicating RA type 0/1. If the RA type is signaled semi-statically by an upper layer (for example, RRC), a field for indicating the RA type is used for the usage status of the second slot (for example, presence / location of UL grant). ) Can be used to provide information.

RRC signal + RBG indication Next, a specific example of a method of using the RRC signal to provide information on the usage status of the second slot (for example, presence / location of UL grant) will be described. Each field of the existing DCI format is maintained as it is, and a method of notifying information related to the DL grant aggregation level or UL grant aggregation level by RRC is possible. In particular, information related to the aggregation level of the DL / UL grant is preferably transmitted RN-specifically. Since the channel quality should be unique for each RN and the channel change should not be fast due to the backhaul characteristics, at least the aggregation level may be signaled by RRC. Here, the information related to the aggregation level may mean the DL / UL grant aggregation level (for example, 1 CCE, 2 CCE, etc.), and also the resource area (or resource allocation) occupied by the DL / UL grant. it can. Of course, the existing RA bit (for example, RBG indication bit) can be reanalyzed and used as it is. By using both RRC signals and RA bit reanalysis, it is not necessary to borrow specific bits in the existing DCI format. For example, the CCE aggregation level can be notified by RRC, and the presence or absence of UL grant in the second slot or the presence or absence of data can be instructed by the DL RA bit. In this way, the presence / absence of UL grant or (R-) PDSCH can be dynamically notified on a subframe basis.

  FIG. 29 shows an example in which UL grant placement is notified by RRC. FIG. 29 illustrates a case where RBG = 4RBs and 4-CCE DL grant. FIG. 29 shows a combination of UL grant arrangements in a total of five cases, but various combinations are possible. If the combination of UL grant placement is limited to 5 cases, 5 types of placement information can be RRC-signaled for each RN. The RA bit (that is, the RBG indication bit) can be used for distinguishing the presence or absence of the UL grant in the corresponding RBG. For example, if any one of (a) to (d) is indicated by RRC signaling, the relay analyzes the use state of the second slot as (a) or (e) by RA bit analysis. be able to. If the size of the RRC signaling bits is not a problem, the arrangement for all cases can be signaled. In this way, optimized resource allocation can be made possible. In this case, when the RA bit is 0, the relay can attempt blind decoding for (a) to (d) in the corresponding RBG. Alternatively, the DCI field (or bit) described with reference to FIG. 28 (eg, type indication bit) may be used in conjunction with or separately from the RA bit analysis to inform the actually transmitted UL grant constellation. it can.

  FIG. 30 shows all the numbers of cases where UL grants can be arranged when RBG = 3 RBs and 2-CCE DL grant. Similarly to FIG. 29, the position of the UL grant is limited using the RRC signal, and the presence or absence of the UL grant can be known from the RBG indication bit.

  FIG. 31 shows all the numbers of cases where UL grants can be arranged when RBG = 1RB and 1-CCE DL grant. Unlike FIG.29 and FIG.30, FIG. 31 has illustrated the case where the allocation unit of UL grant is smaller. 29 and 30 correspond to the case where there is one CCE in the RB of the second slot, and FIG. 31 corresponds to the case where there are two CCEs in the RB of the second slot. Also in this case, similarly to FIG. 29, the position of the UL grant is limited using the RRC signal, and the presence or absence of the UL grant can be known from the RBG indication bit.

  Although the above description has focused on the case where the RRC signaling is an RN-specific signal, this is an example, and the RRC signaling may be an RN-common signal. This is possible when an RN common channel exists. Also, RN-common signals are preferred when the channel characteristics of all relay-base station links are almost similar.

RA Bit Analysis FIG. 32 illustrates more various methods for RA bit analysis. Referring to FIG. 32, the following four methods can be considered for RA bit analysis (Alt # 1 to Alt # 4).

Method # 1 (Alt # 1)
-The RB pair (or frequency domain) that does not include the DL grant in the RBG in which the DL grant is detected is always used for transmission of data (for example, (R-) PDSCH) of the RN that is subject to the DL grant.
-The RA bit for the corresponding RBG indicates the usage of the second slot in the RB pair including the DL grant. As shown in FIG. 32, if the RA bit is 0, there can be UL grant transmission in the corresponding resource area (UL grant / free), and if the RA bit is 1, data is transmitted in the corresponding resource area. The The RA bit can be analyzed in reverse. In some cases, if the RA bit is 0, it can also be assumed that there is always a UL grant transmission in the second slot of the RB pair containing the DL grant.

Method # 2 (Alt # 2)
-The RB pair (or frequency domain) that does not include the DL grant in the RBG in which the DL grant is detected is not always used for the data (R-PDSCH) transmission of the RN that is the DL grant target.
-The RA bit for the RBG indicates the usage of the second slot in the RB pair including the DL grant. As shown in FIG. 32, if the RA bit is 0, UL grant transmission is possible in the resource area (UL grant / free). If the RA bit is 1, data is transmitted in the resource area. The RA bit can be analyzed in reverse.

Method # 3 (Alt # 3)
-In the RBG in which the DL grant is detected, the resource of the second slot in the RB pair including the DL grant is not always used for data transmission of the RN that is the target of the DL grant.
-The RA bit for the corresponding RBG indicates the use of the RB pair (or frequency domain) not including the DL grant. As shown in FIG. 32, if the RA bit is 0, data is not transmitted to the corresponding resource area, and if the RA bit is 1, data is transmitted. The RA bit can be analyzed in reverse.

Method # 4 (Alt # 4)
-In the RBG in which the DL grant is detected, the usage of the remaining resource area excluding the DL grant is indicated by the RA bit of the corresponding RBG.
-As shown in FIG. 32, if the RA bit is 0, data is not transmitted to the corresponding resource area. In this case, the second slot of the RB pair with DL grant can be used for UL grant transmission. If the RA bit is 1, data is transmitted in the entire remaining resource area excluding the DL grant in the RBG. The RA bit can be analyzed in reverse.

  The method of FIG. 32 may be used independently and may be set by higher layer (eg, RRC) signals or physical layer signals. Further, it is possible to fall back to a specific method according to the frequency region occupied by the DL grant. For example, if the number of RB pairs occupied by the DL grant is equal to or greater than a certain number (for example, 3), it is possible to operate in a predetermined method (that is, fallback mode) out of method # 1 and method # 2. . Different methods may be selected and used depending on the transmission mode, presence / absence of interleaving (ie, interleaving mode or non-interleaving mode), R-PDCCH RS type (eg, DM RS, CRS), and the like. In this case, the basic method is set like a fallback operation, and the specific method can be automatically applied according to each configuration mode.

  In the method # 1 to the method # 4 of FIG. As another example, the signal that distinguishes 0 and 1 in the method # 1 to the method # 4 may be a partial bit in DCI (for example, see FIG. 28). As yet another example, the signal that distinguishes 0 and 1 in method # 1 to method # 4 may be an RRC bit. As another example, a signal for distinguishing each state in the method # 1 to the method # 4 may be an indicator of a new format configured by RA bits + RRC bits. For example, four states can be indicated by a combination of RA 1 bit + RRC signal 1 bit. In this case, additional states can be defined for each method. In the method # 1 to method # 4, the signal for distinguishing each state can also be realized by a 2-bit signal composed of RA bits + additional bits (for example, type instruction bits).

  In FIG. 32, the location of the UL grant means a UL grant or an empty state. For the RN, when the UL grant decoding fails, the area is not used for data transmission, and therefore, it remains the same as the empty state at the time of (R-) PDSCH decoding. However, there is a difference between sending a UL grant and not sending it to the base station. Therefore, the notation of the drawings differs depending on which viewpoint is taken.

  FIG. 32 assumes that the DL grant size (aggregation level or resource region) and the UL grant size based on the DL grant size are the same, but this is just an example, and the DL grant and UL grant aggregation levels. The same method can be applied even when are different from each other. In this case, there are more cases for each method, which may require more than 2 bits of signal.

RA Bit Analysis Considering Asymmetrical or Symmetrical Subframe Assignment FIGS. 33 and 34 illustrate cases where DL grant and UL grant always exist as a pair and when they exist separately. Referring to FIGS. 33 and 34, the following six methods can be considered for the analysis of RA bits (Alt # 5 to Alt # 10). RA bits (or other fields or new bits) can be used to indicate DL / UL grant, data location / location.

  In method # 5 (Alt # 5), DL grant is detected across two RB pairs (eg, aggregation level = 2), and UL grant is also the second slot (eg, aggregation level = 2) of two RB pairs. ). In this case, if the instruction bit (for example, RA bit) is 0, it means that there is no data in the resource area where the corresponding RBG remains, and if the instruction bit (for example, RA bit) is 1, the corresponding RBG. Indicates that there is data in the remaining resource area.

  Method # 6 (Alt # 6) and Method # 7 (Alt # 7) can be applied only when only the DL grant exists, that is, when there is no UL grant. Method # 6 means that when the instruction bit (for example, RA bit) is 1, data is filled up to the second slot of the RB pair in which the DL grant exists. On the other hand, in the method # 7 (Alt # 7), when the instruction bit (for example, the RA bit) is 1, no data exists in the second slot of the RB pair in which the DL grant exists, and no DL grant exists. Indicates that data exists only in the remaining RB pairs. If the instruction bit (for example, RA bit) is 0 in the method # 6 / # 7, it means that no data exists in the remaining resources other than the resource having the DL grant in the RBG.

  Method # 8 (Alt # 8), method # 9 (Alt # 9), and method # 10 (Alt # 10) shown in FIG. 34 show a case where the DL grant and UL grant aggregation levels or resource areas do not match. Yes. It should be noted that even if the aggregation level of DL and UL grant is the same due to a single CCE size, DL grant may be placed in 2 RBs and UL grant may be placed in 1 RB. This example means RB mapping as shown rather than an aggregation level.

  The above-described RA analysis method can be applied differently depending on backhaul subframe allocation. As an example, when the DL subframe and the UL subframe are allocated to the backhaul as a pair (that is, when UL grant for the UL backhaul is transmitted in the DL backhaul subframe), the method # 5 and the method # 8 are performed. The RA analysis can be applied under the assumption that the UL grant is always transmitted. On the other hand, in DL subframes without UL subframes that transmit UL grants on the HARQ timeline (which can be referred to as DL stand alone subframes), methods # 6, # 7, # 9, # RA analysis can be applied under the assumption that there is no UL grant, such as 10. That is, according to this method, it is possible to analyze the meaning of signal 0/1 in a subframe in which DL + UL grant exists and in a DL stand alone subframe. For example, even if there is no separate signaling, the relay performs analysis as in methods # 5 and # 8 in a normal subframe, and methods # 6, # 7, # 9, and # 10 in a DL stand-alone subframe. Such an analysis can be automatically applied.

RA Analysis Considering Various Aggregation Levels FIG. 35 explains the role of RA bits in the process of blind decoding when the DL grant and UL grant aggregation levels change.

  Referring to FIG. 35, if the RA bit is 1, it means that the RBG is composed only of DL grant and (R-) PDSCH data. That is, it means that all positions other than the RB in which the DL grant is detected through blind decoding are filled with data and transmitted. On the other hand, if the RA bit is 0, it means that the UL grant always exists. The UL grant aggregation level can be known from blind decoding. That is, when the DL grant blind decoding is successful, RA bit = 0 or RA bit = 1 is applied to a region other than the corresponding RB. When the RA bit = 0, the relay can also know the area occupied by the UL grant from the blind decoding. Therefore, when the UL grant occupies only one RB through blind decoding, the remaining area is filled with data and transmitted. Similarly, when the UL grant exists over a plurality of RBs, the region other than the RB in which the UL grant obtained from the blind decoding exists is used for data. However, if the RB that exists across the UL grant is larger than the RB that exists across the DL grant, the region other than the region in which the DL grant is transmitted can be made empty in the first region. That is, in the RB pair, when only the UL grant is transmitted in the second slot, the first slot of the RB pair can always be vacant. That is, the resource of the first slot in the RB pair in which the UL grant is transmitted is used only for DL grant and not for data.

  On the other hand, although the RA bit is 0, blind grant decoding of the UL grant may fail in the second slot. In this case, the relay must decode the data in a situation where it does not know how far the UL grant exists, which may lead to data decoding failure. In this case, the data decoding can be given up because the UL grant blind decoding failures do not occur frequently. That is, it is preferable to discard the data when UL grant decoding fails.

  FIG. 36 illustrates the role of the RA bit in the process of blind decoding the DL grant and the UL grant, assuming that they are always transmitted together.

  Referring to FIG. 36, it does not occur when the RA bit corresponds to 1 as shown in FIG. In addition, the presence of the UL grant cannot guarantee that the DL grant aggregation level is the same, and the four cases listed when the RA bit is 0 in FIG. 35 are all valid. Therefore, in this example, the RA bit can be used to divide the case of 0 in FIG. 35 into two groups. For example, when the RB occupied by the UL grant is equal to or larger than the RB occupied by the DL grant, the RA bit = 0, and vice versa, the RA bit = 1. In the case of RA bit = 1, since there is always a DL grant + data combination in at least one RB pair, it can be used to indicate this case. It can be known from the blind decoding how many RBs the UL grant actually exists (ie, the aggregation level). Therefore, when blind decoding for UL grant fails, a method of discarding the RBG data can be applied. Here, if additional bits (for example, type indication bits) are further used, all four cases can be distinguished (RA bit + type bit = 2 bits). Therefore, UL grant can be detected without blind decoding. On the other hand, when there is a restriction on the arrangement of DL grant and UL grant, it is possible to signal with one bit without additional bits. For example, two cases can be excluded from the case illustrated in FIG. 36 by limiting the size ratio between the DL grant and the UL grant or by limiting the aggregation level.

Signaling for Instructing One of Resource Usage Methods FIG. 37 illustrates an example of signaling the resource usage method of the second slot. For convenience, FIG. 37 shows again the method # 1 to the method # 4 illustrated in FIG. Therefore, see FIG. 32 for matters relating to method # 1 to method # 4.

  The method # 1 (Alt # 1) will be briefly described with reference to FIG. Method # 1 always has its own data when there is a DL grant. This includes the assumption that the UL grant size is determined according to the DL grant size. For example, there may be an assumption that the UL grant size is smaller or the same as the DL grant size in the actual resource area size aspect or the CCE aggregation level aspect. Method # 1 can be said to be a preferable method in terms of resource utilization and the ability to handle UL grant decoding error cases. However, considering the RS format and interleaving, method # 4, method # 3, etc. may be advantageous. Therefore, a method for selectively applying each method according to circumstances is proposed. For example, both the method # 1 and the method # 4 can be used, and signaling (for example, RRC) for distinguishing between them can be used. Therefore, when DL grant is transmitted by multiple RBGs, it is necessary to assume / limit that the assumption that “RBs that do not include DL grant in one RBG are used for data” are extended to all RBGs equally. It may be. Otherwise, every time the RBG is increased, additional signaling information is requested bit by bit. Of course, when signaling with RRC, the restriction on the number of bits does not matter.

  As another example, methods # 1, # 3, and # 4 can be configured, respectively. Method # 3 can be useful when interleaving is applied. This is because, when interleaved, it is preferable not to use the corresponding resource area for data transmission regardless of whether or not a part of the UL grant exists in the second slot. Therefore, when interleaving is used, it is preferably configured by method # 3. A method in which a method is automatically determined according to a transmission mode may be used together. Also, different methods may be selected and used according to the presence / absence of interleaving (ie, interleaving mode or non-interleaving mode), R-PDCCH RS type (eg, DM RS, CRS), and the like. In this case, the basic method is set like a fallback operation, and the specific method may be automatically applied according to each configuration mode.

Association between DL / UL grant DCI formats
DL / UL grant DCI formats that can be transmitted together through one RB pair can be limited in view of relevance. The relevance can be set using various criteria, for example, using the DCI format size. As an example, if DCI format 1 is used for DL grant, UL grant uses DCI format 0, and if DCI format 2 or 2x is used, DCI format 3 (New UL MIMO format) is used for UL grant. Can do. By doing so, the DL grant size and the UL grant size can be maintained almost the same. In particular, there is no reason why the UL grant size exceeds the DL grant size because the resource area of the second slot in which the UL grant exists is large.

Error Case Handling FIG. 38 illustrates an error case handling method with reference to the case of FIG. Referring to FIG. 38, the presence / absence of data is notified by RA 1 bit, and blind decoding is performed on the UL grant. In this case, additional bits (L1 / L2, RRC signaling) can be used to accurately inform the UL grant size.

  39 and 40 illustrate an error case handling method with reference to FIG.

  Referring to FIG. 39, if the DL grant size is M, the number of UL grants can be limited by limiting the UL grant size N to be smaller than M. For example, when the DL grant size is 3 (= M), maintaining the UL grant size below 2 (= N) (ie, limiting to 1 or 2) may reduce the complexity of blind decoding. it can. Specifically, as shown in the figure, when the aggregation level of the DL grant is 3 CCE and the aggregation level of the UL grant is 2 CCE or less, when the signaling or RA bit is 0 (a) The number of cases from (d) to (c) or (d) is reduced, and the complexity of blind decoding can be reduced.

  40, in addition to the UL grant size limitation described in FIG. 39, is promised between the transceivers so that the case where the signaling bit (eg, RA bit) corresponds to 1 in FIG. 39 (left figure) can be excluded. An example is given. In this case, since it is sufficient to distinguish only two cases (that is, (c) and (d)), the relay can be sufficiently instructed by 1-bit signaling. In other words, as a basic assumption, when the DL grant size is M, the UL grant size (N) must be smaller than M, and the number of UL grant placements must be limited to two. . For example, when the DL grant size is 3 (= M), the UL grant size can be kept smaller than 2 (= N) (that is, limited to 1 or 2) by 1-bit instruction.

Support of “DL Grant Only Case” and “DL Grant + UL Grant Case” FIGS. 41 and 42 illustrate other types of R-PDCCH / data allocation indication rules. In particular, when DL grant + corresponding UL grant exists at the same time, the rules of method # 5 (Alt # 5) and method # 8 (Alt # 8) can be applied, and only DL grant exists (that is, corresponding UL grant) In the absence of the method), the rules of method # 6 (Alt # 6), method # 7 (Alt # 7), method # 9 (Alt # 9), and method # 10 (Alt # 10) can be applied. This will be described in two cases.
(A) When there is a DL grant and there is always a UL grant (b) When there is only a DL grant and there is no applicable UL grant

  In the case of (a), the rules of method # 5 and method # 8 are followed, and in the case of (b), the rules of methods # 6, # 7, # 9, and # 10 are followed. Assuming the case where (a) and (b) coexist, in a specific subframe where the case of (a) occurred, any one of the methods applicable to (a) was used, and (b) occurred In this case, a set can be defined in advance so as to use any one of the methods applicable to (b), and this can be configured by signaling. For example, in the situation as in (a), the arrangement form of R-PDCCH and data is grasped according to the rules of method # 5, and (b) when the situation occurs, the arrangement of R-PDCCH according to the rules presented in method # 6 I can grasp the condition. At this time, method # 5 and method # 6 can be combined into one set and configured using signaling. As another method, the mode setting can be configured using signaling by distinguishing between mode 1 in which only (a) is used and mode 2 in which (a) and (b) are mixed. In general, considering the symmetric subframe allocation, the case of (a) is likely to occur. Of course, (b) also frequently occurs in the TDD structure. In addition, a method in which mode 1 (for example, method # 5) and mode 2 (for example, method # 5 and method # 6) are mixed is also possible. Mode 1 and mode 2 can be automatically applied according to the subframe type. The subframe type can be implicitly grasped from the subframe allocation pattern or the subframe index. When a plurality of methods can be applied in one mode (for example, mode 2 -method # 5 and method # 6), the distinction between method # 5 and method # 6 in mode 2 can depend on blind decoding. In mode 2, the method # 5 and the method # 6 can be distinguished by L1 / L2 or higher layer signaling, and may be implicitly grasped from the subframe allocation pattern or the subframe index.

Index Arrangement for Maximizing Backhaul Resources The following description assumes the following assumptions for the use of backhaul resources. For purposes of explanation, assume that there are R-PDCCH (or relay) groups 0, 1, and 2. In this case, since it is assumed that the R-PDCCH is always present in the first slot of the RB pair in the group to which the relay belongs (for example, group 1), only the second slot of the RB pair is used for the R-PDSCH. be able to. In contrast to this, when attempting to transmit R-PDSCH using an RB pair of another group (group 0 or 2) (that is, when there is an RA instruction), the first slot in addition to the second slot Also can be used for R-PDSCH transmission. This is possible by analyzing the RA indication bit by distinguishing between the group to which the relay belongs and the group to which the relay does not belong.

  FIG. 43 shows an example of allocating R-PDCCH according to the order of group indexes. FIG. 43 assumes a case where the RBG is composed of 4 RBs and the total number of R-PDCCHs is 8.

  Referring to FIG. 43, eight R-PDCCHs (RN1 to RN8) can be sequentially arranged starting from RB index 0 in accordance with the order of group indexes (for example, the order of logical RB indexes). In this case, RN4 belonging to group 1 cannot use the first slot of the RB pair belonging to group 0. This is because RBs (RB indexes 0 to 2) before RN4 of group 1 are all filled with R-PDCCHs (RN1 to RN3) of other RNs. In this case, the existing assumption described above (that is, the assumption that R-PDSCH transmission can be started from the first slot when there is an RA instruction in a group other than group 1 to which RN4 belongs) becomes incompatible. Therefore, a new rule is required when applying an array of group indexes as shown. It must also be determined how to arrange the group index.

  As one method, a high index value can be given to the RN that the base station has to send a relatively large amount of data (eg, group 2). On the other hand, a relatively low index value can be given to an RN that the base station has to send a relatively small amount of data, or an RN that has no data to send (eg, DL grant only case). At this time, in order to apply the rules correctly, it is preferable to first arrange the group indexes based on the data amount. When arranged in this way, the relay separates the RA indication bit separately when there is a resource assigned to an RB index lower than itself and when a resource assigned to an RB index higher than itself exists. Can be analyzed. The contents relating to this are shown in FIGS. Each figure illustrates a different situation.

  FIG. 44 exemplifies a case where each RB means a logical RB and an index, or a case of resource allocation in units of 1 RB. FIG. 45 illustrates a method in the case of resource allocation in units of RBGs. FIG. 45 illustrates a case where UL grants are separately packed and interleaved at a time or in units of a certain size group.

  FIG. 44 shows a case where an attempt is made to use free resources for RN6 when the second slot of the RB pair in which the DL grant of RN2 exists is free (for example, the case of only DL grant). Show. FIG. 44 shows a case where data for RN6 is transmitted to the second slot of the RB pair in which the DL grant of RN6 exists and the RB pair not used by another RN in addition to the above-described free resources. Show. That is, a larger amount of data is transmitted by RN6 than RN1 or RN2. This is because it is assumed that the array of group indexes is arranged in the size of data to be sent to the corresponding relay. In this case, the RA bit analysis must be set differently for each. That is, the RA bit for RBs (RBs in the left direction) existing before RN6 simply informs whether or not there is data in the second slot. This is because the first slot is already occupied by an RN having a low group index value such as RN2. On the other hand, when the R-PDSCH of the RN 6 is allocated to an RB (RBs in the right direction) larger than the RB index in which the RN 6 exists, the RA bit has the R-PDSCH in both the first slot and the second slot. Tell whether or not. That is, the relay may perform decoding assuming that the R-PDSCH is transmitted in the second slot of the RB pair or all slots in consideration of the group index. The above assumptions can be arranged as follows:

  1. The RA bits are data (eg, (R-) for the RB pair occupied by its own R-PDCCH (or its own R-PDCCH group) and the previous R-PDCCH (or R-PDCCH group) in the search space. When instructing (PDSCH) allocation, the relay assumes that the DL grant is transmitted in the first slot of the corresponding RB pair, and its own data is transmitted in the second slot. Therefore, the relay performs (R-) PDSCH decoding on the assumption that there is no data transmission in the first slot in the corresponding RB pair.

  2. When the RA bit indicates data (eg, (R-) PDSCH) allocation for RB pairs after the RB pair occupied by its own R-PDCCH in the search space (ie, higher index RB). The relay assumes that data is transmitted in both the first and second slots of the corresponding RB pair. Therefore, the relay assumes that there is data transmission in both the first slot and the second slot of the corresponding RB pair, and performs (R-) PDSCH decoding.

  According to the proposal, the relay does not need to know how many RBs are used by the R-PDCCH and how many R-PDCCH groups exist in a given subframe.

  FIG. 45 is an example when the RBG concept is introduced. When resources are allocated in units of RBGs, all PRBs belonging to the RBG may not be used. The more RBs that cannot be used in this way, the more efficiently the backhaul resource can be used by the above-described proposed method. FIG. 45 shows a case in which one RB of the RBG to which RN1 belongs is used for RN2, and the R-PDSCH for RN2 is transmitted even in the RB pair in which there is no R-PDCCH of RN in addition to the RBG to which RN2 belongs. Indicates. In this case, it can be seen that the RA bit analysis for the RBG index having an index lower than the RBG to which RN2 belongs is different from the RA bit analysis for the PRB when the index is larger than the RBG index to which RN2 belongs.

  FIG. 46 shows an example in which UL grant is packed together with a low index when UL grant is less than DL grant. By doing so, all RBs other than the RBs occupied by the UL grant can be used in the proposed rule.

  Although the above description has been focused on the relationship between the base station and the relay, the above description may be applied to the relationship between the relay and the terminal in the same / similar manner. For example, in the above description, the base station may be replaced with a relay, and the relay may be replaced with a terminal.

  FIG. 47 illustrates a base station, a relay, and a terminal applicable to the present invention.

  Referring to FIG. 47, the wireless communication system includes a base station (BS) 110, a relay (RN) 130, and a terminal (UE) 130. For convenience, a terminal connected to a relay is shown, but the terminal may be connected to a base station.

  The base station 110 includes a processor 112, a memory 114, and a radio frequency (RF) unit 116. The processor 112 may be configured to implement the procedures and / or methods proposed in the present invention. The memory 114 is connected to the processor 112 and stores various information related to the operation of the processor 112. The RF unit 116 is connected to the processor 112 and transmits and / or receives wireless signals. The terminal 120 includes a processor 122, a memory 124, and an RF unit 126. The processor 122 may be configured to implement the procedures and / or methods proposed in the present invention. The memory 124 is connected to the processor 122 and stores various information related to the operation of the processor 122. The RF unit 126 is connected to the processor 122 and transmits and / or receives a radio signal. The terminal 130 includes a processor 132, a memory 134, and an RF unit 136. The processor 132 can be configured to implement the procedures and / or methods proposed in the present invention. The memory 134 is connected to the processor 132 and stores various information related to the operation of the processor 132. The RF unit 136 is connected to the processor 132 and transmits and / or receives a radio signal. Base station 110, relay 120 and / or terminal 130 may have a single antenna or multiple antennas.

  In the embodiment described above, the constituent elements and features of the present invention are combined in a predetermined form. Each component or feature should be considered optional unless stated otherwise. Each component or feature may be implemented in a form that is not combined with other components or features, or some components and / or features may be combined to form an embodiment of the present invention. The order of operations described in the embodiments of the present invention can be changed. Some configurations or features of one embodiment may be included in another embodiment or may replace a corresponding configuration or feature of another embodiment. It is obvious that claims which are not explicitly cited in the claims can be combined to constitute an embodiment, or can be included as new claims by amendment after application.

  In this document, the embodiments of the present invention are mainly described with reference to data transmission / reception relationships among terminals, relays, and base stations. The specific operation assumed to be performed by the base station in this document may be performed by its upper node in some cases. That is, it is clear that various operations performed for communication with a terminal in a network including a plurality of network nodes including a base station can be performed by the base station or another network node other than the base station. . The base station may be replaced with terms such as a fixed station, Node B, eNode B (eNB), access point, and the like. Moreover, a terminal can be substituted for terms such as user equipment (User Equipment: UE), a mobile station (Mobile Station: MS), and a mobile subscriber station (Mobile Subscriber Station: MSS).

  Embodiments according to the present invention may be implemented by various means such as hardware, firmware, software, or a combination thereof. When implemented in hardware, one embodiment of the present invention includes one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), and digital signal processors (Digital). The present invention can be realized by Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

  In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, or the like that performs the functions or operations described above. The software code can be stored in a memory unit and driven by a processor. The memory unit is provided inside or outside the processor, and can exchange data with the processor by various known means.

  It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the characteristics of the present invention. Therefore, the above detailed description should not be construed as limiting in any way, and should be considered exemplary. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes that come within the equivalent scope of the invention are included in the scope of the invention.

  The present invention relates to a wireless communication system, and is specifically applicable to a base station, a relay, and a terminal.

110 base station 112 processor 114 memory 116 RF unit 120 relay 122 processor 124 memory 126 RF unit 130 terminal 132 processor 134 memory 136 RF unit 301 scramble module 302 modulation mapper 303 layer mapper 304 precoding module 305 resource element mapper 306 OFDMA signal generator 500 Subframe 501 Slot 502 Symbol 503 RB
504 Data area 505 Control area 506 SRS transmission area

Claims (8)

A method for receiving a physical downlink control channel (R-PDCCH) signal of a relay in a relay of a wireless communication system, comprising:
Receiving first control information for downlink scheduling in a first slot of a resource block (RB) pair set, wherein the first control information includes allocation information on one or more resource units; Having
Monitoring second control information for uplink scheduling in a second slot of the RB pair set;
Performing a process of receiving data corresponding to the first control information,
When the assigned resource unit or units overlap with the RB pair in which the first control information is detected, the process of receiving the data is performed in the second slot of the RB pair. A method performed under the assumption that it exists.   The resource unit allocation information includes a bitmap for resource allocation, and each bit indicates whether to allocate a resource to a corresponding RB or resource block group (RBG). Method. Monitoring the second control information comprises:
The method according to claim 1, wherein the method is performed under an assumption that an aggregation level of the second control information is smaller than an aggregation level of the first control information.   The method of claim 1, further comprising: receiving information related to an arrangement of the second control information on a resource of the second slot through higher layer signaling. An apparatus used in a wireless communication system,
A radio frequency (RF) unit;
And a processor,
The processor is
Receiving first control information for downlink scheduling in a first slot of a resource block (RB) pair set, wherein the first control information comprises allocation information for one or more resource units;
Monitoring second control information for uplink scheduling in the second slot of the RB pair set;
Configured to receive data corresponding to the first control information;
When the assigned resource unit or units overlap with the RB pair in which the first control information is detected, the process of receiving the data is performed in the second slot of the RB pair. User equipment performed under the assumption that it exists.   The resource unit allocation information includes a bitmap for resource allocation, and each bit indicates whether to allocate a resource to a corresponding RB or resource block group (RBG). apparatus. Monitoring the second control information comprises:
The apparatus according to claim 5, which is performed under an assumption that an aggregation level of the second control information is smaller than an aggregation level of the first control information. The processor further includes:
6. The apparatus of claim 5, configured to receive information regarding placement of the second control information on the resources of the second slot through higher layer signaling.

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