KR20130118726A - Method for transmitting sounding reference signal in wireless communication system and apparatus therefor - Google Patents

Abstract

PURPOSE: A method for transmitting a sounding reference signal in a wireless communication system and an apparatus for the same are provided to efficiently use downlink resources in the wireless communication system. CONSTITUTION: A base station (BS) (110) comprises a processor (112), a memory (111), and a radio frequency (RF) unit (116). The memory is connected to the processor to store various information associated with the operation of the processor. The RF unit is connected to the processor to transmit or receive a radio signal. A relay (120) comprises a processor (122), a memory (124), and an RF unit (126). The RF unit of the relay is connected to the processor to transmit or receive a radio signal. User equipment (UE) (130) comprises a processor (132), a memory (134), and an RF unit (136). The RF unit of the UE is connected to the processor to transmit or receive a radio signal. [Reference numerals] (110) Base station (BS); (111,124,134) Memory; (112,122,132) Processor; (116,126,136) RF unit; (120) Relay (RN); (130) Terminal (UE)

Description

Method and apparatus for receiving downlink signal

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

Background of the Invention [0002] Wireless communication systems are widely deployed to provide various types of communication services such as voice and data. Generally, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Examples of multiple access systems include a code division multiple access (CDMA) system, a frequency division multiple access (FDMA) system, a time division multiple access (TDMA) system, an orthogonal frequency division multiple access (OFDMA) system, a single carrier frequency division multiple access (MC-FDMA) system, and a multi-carrier frequency division multiple access (MC-FDMA) system.

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

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

In one aspect of the present invention, a method for receiving a downlink signal in a wireless communication system, the method comprising: receiving a downlink control channel signal having a carrier indication field (CIF) and resource allocation information; And receiving a downlink shared channel signal from at least one resource block indicated by the resource allocation information in a subframe, wherein the downlink shared channel signal exists in the subframe. Multiplexing) is provided, the start position of the symbol is indicated using the bit information of the CIF.

In another aspect of the present invention, a communication apparatus configured to receive a downlink signal in a wireless communication system, comprising: a radio frequency (RF) unit; And a microprocessor, wherein the microprocessor receives a downlink control channel signal having a carrier indication field (CIF) and resource allocation information and is downward from one or more resource blocks indicated by the resource allocation information in a subframe. A communication device configured to receive a link shared channel signal, wherein a start position of an orthogonal frequency division multiplexing (OFDM) symbol in which the downlink shared channel signal is present in the subframe is indicated using bit information of the CIF Is provided.

Preferably, some of the bit information of the CIF indicates a carrier in which the downlink shared channel signal exists, and the remaining of the bit information of the CIF indicates a start position of an OFDM symbol in which the downlink shared channel signal exists. .

Preferably, some of the bit information of the CIF indicates a resource use state in the second slot of the subframe, and the remaining of the bit information of the CIF indicates the start position of an OFDM symbol in which the downlink shared channel signal is present. Instruct.

Preferably, the bit information of the CIF indicates a difference between a start position of an OFDM symbol in which a downlink control channel signal exists and a start position of an OFDM symbol in which the downlink shared channel signal exists in the subframe.

Preferably, the start position of the OFDM symbol in which the downlink shared channel signal is present is indicated using bit information of the CIF and a control format indicator (CFI) value.

Preferably, the CFI value is received using a Radio Resource Control (RRC) signal.

Preferably, the downlink control channel signal is a relay physical downlink control channel (R-PDCCH) signal, and the downlink shared channel signal is a relay physical downlink shared channel (R-PDSCH) signal.

According to an embodiment of the present invention, downlink resources can be efficiently used in a wireless communication system.

The effects obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 illustrates a structure of a radio frame of a 3GPP system.
2 illustrates a resource grid for a downlink slot.
3 illustrates a structure of a downlink subframe.
4 illustrates a structure of an uplink subframe used in a system.
5 illustrates a wireless communication system including a relay.
6 illustrates backhaul communication using a Multi-Media Broadcast over a Single Frequency Network (MBSFN) subframe.
7 illustrates a Carrier Aggregation (CA) communication system.
8 shows an example of indicating a carrier using a CIF field.
9 shows an example of informing the control region size of each carrier.
10 to 14 illustrate a method of notifying a starting point of a (R-) PDSCH (or R-PDCCH) in a backhaul subframe according to an embodiment of the present invention.
15 illustrates a base station, a relay, and a terminal applicable to the present invention.

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

The following embodiments are mainly described in the case where the technical features of the present invention is applied to the 3GPP system, but this is by way of example and the present invention is not limited thereto.

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

Referring to FIG. 1, a radio frame has a length of 10 ms (307200 · T _s ) and consists of 10 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 the 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 a plurality of resource blocks (RBs) in the frequency domain. In the LTE system, one resource block includes 12 subcarriers x 7 (6) OFDM or SC-FDMA symbols. A transmission time interval (TTI), which is a unit time at which data is transmitted, may be determined by one or more subframes. The structure of the above-described radio frame is only 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.

2 illustrates a resource grid for a downlink slot.

개의 RE로 구성되어 있다.

은 하향링크 슬롯에 포함된 OFDM 심벌의 개수이고

는 자원블록에 포함된 부반송파의 개수이다. 하향링크 슬롯에 포함되는 자원블록의 수(N^DL _RB)는 셀에서 설정되는 하향링크 전송 대역폭(bandwidth)에 종속한다.Referring to FIG. 2, the downlink slot includes a plurality of OFDM symbols in the time domain and includes N ^DL _RB resource blocks in the frequency domain. Since each resource block includes 12 subcarriers, the downlink slot includes N ^DL _RB × 12 subcarriers in the frequency domain. FIG. 2 illustrates that the downlink slot includes 7 OFDM symbols and the resource block includes 12 subcarriers, but is not limited thereto. For example, the number of OFDM symbols included in the downlink slot may be modified according to the length of the cyclic prefix (CP). Each element on the resource grid is called a resource element (RE). The RE is a minimum time / frequency resource defined in a physical channel, indicated by one OFDM symbol index and one subcarrier index. One resource block

It consists of two REs.

Is the number of OFDM symbols included in the downlink slot

Is the number of subcarriers included in the resource block. The number N ^DL _RB of resource blocks included in the downlink slot depends on a downlink transmission bandwidth set in a cell.

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

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

Referring to FIG. 3, at least one OFDM symbol is used as a control region from the beginning of a subframe and the remaining OFDM symbols are used as a data region. The size of the control region may be set independently for each subframe. The control region is used to transmit scheduling information and other L1 / L2 (layer 1 / layer 2) control information. The data area is used to carry traffic. The control channel includes a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid-automatic Repeat Request (ARQ) Indicator CHannel (PHICH), and a Physical Downlink Control CHannel (PDCCH). The traffic channel includes a Physical Downlink Shared CHannel (PDSCH).

The PDCCH notifies each terminal or group of terminals of information related to resource allocation of a paging channel (PCH) and a downlink-shared channel (DL-SCH), an uplink scheduling grant, and HARQ information. A paging channel (PCH) and a downlink-shared channel (DL-SCH) are transmitted through the PDSCH. Therefore, the BS and the MS generally transmit and receive data via the PDSCH, except for specific control information or specific service data. Control information transmitted through the PDCCH is called downlink control information (DCI). DCI indicates uplink resource allocation information, downlink resource allocation information, and uplink transmission power control command for arbitrary UE groups. The base station determines the PDCCH format according to the DCI to be transmitted to the UE, and attaches a CRC (Cyclic Redundancy Check) to the control information. In the CRC, a unique identifier (eg, a Radio Network Temporary Identifier (RNTI)) is masked according to an owner or a purpose of the PDCCH.

4 illustrates a structure of an uplink subframe used in a 3GPP system.

Referring to FIG. 4, a subframe 500 having a length of 1 ms, which is a basic unit of LTE uplink transmission, is composed of 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 one slot in the time domain. The structure of an uplink subframe of LTE is largely divided into a data region 504 and a control region 505. The data area means a communication resource used in transmitting data such as voice and packet transmitted to each terminal, and includes a PUSCH (Physical Uplink Shared Channel). The control region means a communication resource used to transmit an uplink control signal, for example, a downlink channel quality report from each terminal, a received ACK / NACK for an uplink signal, an uplink scheduling request, and a PUCCH (Physical Uplink). Control Channel). The sounding reference signal (SRS) is transmitted through the SC-FDMA symbol located last on the time axis in one subframe. The SRSs of the UEs transmitted in the last SC-FDMA of the same subframe can be classified according to the frequency location / sequence.

5 illustrates a communication system including a relay (or relay node (RN)). The relay extends the service area of the base station or installs it in the shadow area to smooth the service. Referring to FIG. 5, a wireless communication system includes a base station, a relay, and a terminal. The terminal performs communication with the base station or the relay. For convenience, a terminal communicating with a base station is referred to as a macro UE, and a terminal communicating with a relay is referred to as a relay UE. The communication link between the base station and the macro terminal is referred to as a macro access link, and the communication link between the relay and the relay terminal is referred to as a relay access link. The communication link between the base station and the relay is also referred to as a backhaul link.

Relays can be classified into L1 (layer 1) relays, L2 (layer 2) relays, and L3 (layer 3) relays depending on how much function they perform in multi-hop transmission. The brief features of each are as follows. The L1 relay normally performs the function of a repeater and simply amplifies the signal from the base station / terminal and transmits it to the terminal / base station. Since it does not perform decoding in the relay, it has a merit of short transmission delay. However, since it can not distinguish between a signal and noise, it has a disadvantage that it is amplified to noise. In order to overcome such disadvantages, an advanced repeater (smart repeater) having functions such as UL power control or self-interference cancellation may be used. The operation of the L2 relay may be expressed as decode-and-forward and may transmit user plane traffic to L2. There is an advantage that the noise is not amplified but the delay due to decoding increases. The L3 relay is also referred to as self-backhauling and can transmit IP packets to L3. It also includes Radio Resource Control (RRC) functionality, which acts like a small base station.

The L1 and L2 relays may be described as a case where the relay is part of a donor cell covered by the corresponding base station. When the relay is part of the donor cell, the relay cannot have its own cell ID because the relay does not control the cell of the relay itself and the terminals of the cell. However, the relay ID, which is the ID of the relay, can be obtained. In this case, some functions of RRM (Radio Resource Management) 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 is when the relay can control its own cell. In this case, the relay can manage more than one cell, and each cell managed by the relay can have a unique physical-layer cell ID. It may have the same RRM mechanism as the base station, and from the terminal's point of view, there is no difference between connecting to a cell managed by a relay or a cell managed by a general base station.

Relays are classified as follows according to mobility.

- Fixed Relay (Fixed RN): It is permanently fixed and used for shadow area or cell coverage increase. The function of a simple repeater is also possible.

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

- Mobile Relay (RN): Relays that can be mounted on public transit such as buses and subways. Relay mobility should be supported.

In addition, the following distinction is possible depending on the link between the relay and the network.

In-band connection: The network-to-relay link and the network-to-end link in the donor cell share the same frequency band.

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

In addition, the following classification is possible according to whether the terminal recognizes the presence of a relay.

Transparent relay: The terminal cannot know that communication with the network is performed through the relay.

Non-transparent relay: The terminal knows that communication with the network is performed through the relay.

6 shows an example of performing backhaul transmission using an MBSFN subframe. In in-band relay mode, the base station-relay link (ie, backhaul link) operates in the same frequency band as the relay-end link (ie, relay access link). In a case where a relay transmits a signal to a terminal while receiving a signal from a base station and vice versa, the transmitter and the receiver of the relay cause interference with each other, so that transmission and reception of the relay at the same time may be restricted. To this end, the backhaul link and the relay access link are partitioned in a TDM manner. LTE-A establishes a backhaul link in the MBSFN subframe (fake MBSFN method) to support the measurement operation of the legacy LTE terminal in the relay zone. When an arbitrary subframe is signaled as an MBSFN subframe, the UE receives only the control region (ctrl) of the corresponding subframe, so that the relay can construct a backhaul link using the data region of the corresponding subframe. As an example, the relay PDCCH (R-PDCCH) may be transmitted using a specific resource region in the last OFDM symbol from a specific OFDM symbol of the MBSFN subframe.

7 illustrates a Carrier Aggregation (CA) communication system. The LTE-A system uses a carrier aggregation or bandwidth aggregation technique that uses a larger uplink / downlink bandwidth by aggregating a plurality of uplink / downlink frequency blocks for a wider frequency band. Each frequency block is transmitted using a component carrier (CC). CC may be understood as a carrier frequency (or center carrier, center frequency) for a corresponding frequency block.

Referring to FIG. 7, respective CCs may be adjacent to each other or non-adjacent in the frequency domain. The bandwidth of each component carrier can be determined independently. It is also possible to merge asymmetric carriers in which the number of UL CCs and the number of DL CCs are different. For example, in case of two DL CCs and one UL CC, the configuration may be configured to correspond to 2: 1. The DL CC / UL CC link can be fixed to the system or semi-static. Also, even if the entire system band consists of N CCs, the frequency band that a specific terminal can monitor / receive can be limited to M (<N) CCs. The various parameters for carrier merging may be set in a cell-specific, UE group-specific or UE-specific manner. Meanwhile, the control information may be set to be transmitted and received only through a specific CC. This particular CC may be referred to as a primary CC (or PCC) (or anchor CC), and the remaining CC may be referred to as a secondary CC (SCC).

3GPP uses the concept of a cell for the management of radio resources. A cell is defined as a combination of a downlink resource and an uplink resource, and an uplink resource is not essential. Therefore, the cell can be composed of downlink resources alone or downlink resources and uplink resources. If carrier merging is supported, the linkage between the carrier frequency (or DL CC) of the downlink resource and the carrier frequency (or UL CC) of the uplink resource may be indicated by the system information. A cell operating on the primary frequency (or PCC) may be referred to as a primary cell (PCell), and a cell operating on the secondary frequency (or SCC) may be referred to as a secondary cell (SCell). The PCell is used by the terminal to perform an initial connection establishment process or to perform a connection re-establishment process. The PCell may refer to the cell indicated in the handover process. The SCell is configurable after the RRC connection is established and can be used to provide additional radio resources. PCell and SCell may be collectively referred to as a serving cell. Therefore, in the case of the UE that is in the RRC_CONNECTED state, but carrier aggregation is not configured or does not support carrier aggregation, there is only one serving cell configured only with the PCell. On the other hand, in the case of the UE in the RRC_CONNECTED state and the carrier aggregation is configured, one or more serving cells exist, and the entire serving cell includes the PCell and the entire SCell. For carrier aggregation, after the initial security activation process is initiated, the network may configure one or more SCells for the UE supporting carrier aggregation in addition to the PCell initially configured in the connection establishment process.

As described with reference to FIG. 7, the 3GPP LTE-A system is designed to use multiple carriers and can introduce up to five carriers to the downlink / uplink. For example, the system may be configured with two downlink carriers and two uplink carriers. One of the two carriers is the primary carrier and the other is the secondary carrier. If cross carrier scheduling is set, the primary carrier may perform scheduling for the secondary carrier. For cross carrier scheduling, the downlink control information (DCI) transmitted on the primary carrier has a Carrier Indication Field (CIF) field. The CIF field is used to indicate which carrier the DCI on the primary carrier schedules. For example, when the CIF field is 3 bits, 8 carriers may be indicated.

8 shows an example of indicating a carrier using a CIF field. Suppose there are five carriers (CC # 1 to # 5) and CC # 1 is the primary carrier. Referring to FIG. 8, when cross-carrier scheduling is set, the base station transmits a DCI having a CIF field on the primary carrier CC # 1 to the terminal. DCI includes DCI for UL scheduling or DCI for DL scheduling. The DCI transmitted on CC # 1 is applied to CCs (eg, CC # 3 and CC # 5) indicated by the CIF field.

9 shows an example of informing the control region size of each carrier. The control region size (e.g., the number of OFDM symbols) of each carrier is indicated using a control format indicator (CFI). The CFI for the carrier may be delivered to the terminal by a higher layer signal (eg, an RRC signal). The figure shows one downlink subframe for each carrier and the number in the box represents the OFDM symbol index.

Referring to FIG. 9, CFI may be independently provided for each CC. In a 3GPP system, a control region (eg, PDCCH) and a data region (eg, PDSCH) are separated by a TDM scheme. Accordingly, the terminal interprets the left side as the control region and the right side as the data region based on the OFDM symbol indicated by the CFI. When the control area and the data area are identified, the terminal decodes the control information (eg, PDCCH signal) and data (eg, PDSCH signal) in each area.

In the backhaul link CIF Using Signaling

The DCI format with the CIF field can also be used for the relay backhaul link. DCI format for multi-carrier is useful when carrier aggregation is introduced in the backhaul link. However, even when only a limited number of carrier merges are introduced into the backhaul link (eg, 2) or no carrier merge is performed, the DCI format having the CIF field may be used. In this case, the CIF field defined in the DCI format may be used not only for its original purpose but also for conveying other meanings. For example, if only two carriers are used for the backhaul link, the cross carrier scheduling information only needs 2 bits. In addition, it can be assumed that the primary carrier is always scheduled in the backhaul link. In this case, 1 bit is sufficient for information for cross-carrier scheduling. Therefore, the extra 1 bit or 2 bits in the CIF field can be used for other purposes.

Hereinafter, a method of signaling a usage state of a backhaul resource using a CIF field will be described with reference to the drawings. In the following description, eNB PDCCH indicates a PDCCH transmitted by the base station to the terminal. The RN PDCCH indicates a PDCCH transmitted by the relay to the UE. R-PDCCH represents a PDCCH transmitted by the base station to the relay. The (R-) PDSCH indicates a PDSCH transmitted by a base station to a relay. Resource allocation for the PDSCH may be made in resource block units, resource block group units or on one or more consecutive resource blocks according to a resource allocation type.

R-PDCCH is classified into a DL grant (DG) and an UL grant (Uplink Grant, UG). The DL grant includes information on time / frequency / spatial resources of the (R-) PDSCH corresponding to data to be received by the relay and information for decoding (in other words, scheduling information). The UL grant includes information on time / frequency / spatial resources of the (R-) PUSCH corresponding to data to be transmitted by the relay in uplink and information for decoding (in other words, scheduling information). The DL grant is in the RB of the first slot and the UL grant is in the RB of the second slot.

According to the present invention, the extra bits in the CIF field may be used for indicating, for example, what information exists in the relay backhaul subframe. Specifically, when the R-PDCCH exists in the first slot / region, an extra bit in the CIF field is used to indicate what information (eg, R-PDCCH or (R-) PDSCH) exists in the second slot / region. Can be used as More specifically, the extra bit in the CIF field may be used to indicate what information (eg, UL grant, (R-) PDSCH) is present in the second slot of the RB pair in which the R-PDCCH is detected.

As another example, according to the present invention, the CIF field may be used to designate a starting point of the (R-) PDSCH (or R-PDCCH) in a subframe. The following cases are possible.

A. Some or all of the CIF fields in the R-PDCCH (DCI format) dynamically change the number of symbols of the start symbol of the (R-) PDSCH or the symbol number of the eNB PDCCH (or RN PDCCH) (e.g., subframe-by-subframe). Can be used to specify. When the CIF field is used to indicate the number of symbols of the eNB PDCCH (or RN PDCCH), the relay may determine the start position of the (R-) PDSCH based on the number of symbols of the eNB PDCCH (or RN PDCCH). For example, the relationship between the start position of the (R-) PDSCH and the number of symbols in the eNB PDCCH (or RN PDCCH) is specified in advance (e.g., in the form of an offset), so that the relay can be configured from the CIF field to the eNB PDCCH (or RN PDCCH). It is possible to determine the number of symbols and determine the starting position of the (R-) PDSCH from the number of symbols of the eNB PDCCH (or RN PDCCH). The following situations may exist.

(a) The case where the R-PDCCH start symbol is fixed: The case where the position of the R-PDCCH is fixed in the time domain and only the start position of the (R-) PDSCH is changed. Since the resource region of the R-PDCCH is fixed in the time domain, the relay only needs to perform blind decoding for receiving the R-PDCCH only within the corresponding time resource region. When an R-PDCCH (DL grant) is detected, the relay receives (R-) PDSCH signal from one or more resource blocks indicated by the DL grant and performs decoding. At this time, the time resource region in which the (R-) PDSCH signal is present is indicated using bit information of the CIF.

i. Carrier merge case

For example, some bits (eg 2 bits) in the CIF field may be used for the original CIF purpose and the remaining bits (eg 1 bit) may be used to specify the (R-) PDSCH start position. Since the number of RN PDCCH symbols can be fixed to 1 or 2, there are only two significant positions where there can be a start symbol of (R-) PDSCH (eg, OFDM symbols # 2, # 3) (when indexing from # 0). In this case, the (R-) PDSCH start position may be designated as 1 bit.

ii. Non-CA case

Even if a CA is not set, if a DCI format with CIF is predetermined to be used, all bits of the CIF may be used for specifying a (R-) PDSCH start position.

Alternatively, one bit may be used for specifying a (R-) PDSCH start position in the CIF field, and the remaining bits may be used for resource allocation (RA). For example, if downlink resource allocation is made in RBG (Resource Block Group) units, and one RBG consists of three RBs, the remaining two bits in the CIF field are the first and second of three RB pairs constituting the RBG. It can be used to indicate what information is transmitted in the resource area (eg, slot). Here, the RBG associated with the CIF field may be limited to the RBG from which the DL grant is detected.

If the DCI format without CIF is used, some bits in the existing RA bits may be used to inform (R-) PDSCH start position and / or information about the second slot (eg, usage state).

(b) When the R-PDCCH start symbol is changed (semi-static / semi-dynamically): The start position of the R-PDCCH / (R-) PDSCH in the time domain may be changed. However, a period in which the start position of the R-PDCCH and the start position of the (R-) PDSCH are varied may be different. For example, in order to reduce system complexity, the variation of the R-PDCCH start symbol may be semi-static / semi-dynamic. When the variable of the R-PDCCH start symbol is indicated using the CIF, the R-PDCCH start symbol may not be known until the R-PDCCH is received. Accordingly, the relay must perform blind decoding for R-PDCCH reception in a plurality of candidate time resource regions. If an R-PDCCH (DL Grant) is detected, the relay can identify the start symbol of the R-PDCCH therefrom. The relay then receives the (R-) PDSCH signal from one or more resource blocks indicated by the DL grant and performs decoding. At this time, the time resource region in which the (R-) PDSCH signal is present is indicated using bit information of the CIF.

i. Carrier merge case

As described above, some bits (eg 2 bits) in the CIF field may be used for the original CIF purpose and the remaining bits (eg 1 bit) may be used to specify the (R-) PDSCH start position.

ii. Non-CA case

Even if a CA is not set, if a DCI format with CIF is predetermined to be used, all bits of the CIF can be used to specify the (R-) PDSCH start symbol position.

Alternatively, one bit may be used for specifying a (R-) PDSCH start position in the CIF field, and the remaining bits may be used for RA. For example, one bit in the CFI field indicates whether the (R-) PDSCH start position is OFDM symbol # 2 or # 3, and the remaining two bits are R-PDCCH / (R-) PDSCH / empty placement ( can be used to indicate placement.

B. CIF information is used to carry semi-static information about the number of symbols of the start symbol of the (R-) PDSCH or the RN PDCCH.

(a) The start position of the (R-) PDSCH and the R-PDCCH may be transmitted using CIF. This method may be combined with the method of notifying the RRC of the starting positions of the (R-) PDSCH and the R-PDCCH or may be used separately if necessary. In particular, since the CIF field is a dynamic information field, it can be used to convey more specific information since it is sufficiently free to use it for carrying semi-static information. For example, in the case of indicating the start position of the (R-) PDSCH / R-PDCCH using 2 bits in the CIF field, the first 1 bit gives information about the start position, and the second 1 bit is semi-static. Can be toggled to In this case, whether the (R-) PDSCH and / or R-PDCCH start position is changed by toggling the second 1-bit information may be changed, and the start position may be changed by using the received 1-bit information.

Hereinafter, a method of informing a starting point of (R-) PDSCH (or R-PDCCH) using a CIF field will be described in more detail with reference to FIGS. 10 to 14. The figure corresponds to one downlink subframe (eg, MBSFN subframe) and the number in the box represents the OFDM symbol index. To help understand the invention, only the R-PDCCH for the DL grant and the corresponding (R-) PDSCH are shown in the figure.

FIG. 10 illustrates a method of dynamically informing a (R-) PDSCH start position using CIF in a state in which a start position of the R-PDCCH is fixed. Referring to FIG. 10, the location of the R-PDCCH is fixed to OFDM symbol # 3. As a method of fixing the R-PDCCH, a permanent or semi-static manner may be used. If the start position of the R-PDCCH is semi-statically fixed, RRC signaling is required to support variability. On the other hand, the start position of the (R-) PDSCH is dynamically indicated using CIF. This example illustrates the case where the start position of the (R-) PDSCH is indicated by OFDM symbol # 2. Accordingly, the relay decodes using resources of OFDM symbols # 3 to # 6 for R-PDCCH reception and decodes using resources of OFDM symbols # 2 to # 6 for R-PDSCH reception.

The indication of the start position of the (R-) PDSCH using the CIF may be variously implemented. For example, at least some bits (eg, 1 or 2 bits) in the CIF field may directly indicate a start position (eg, OFDM symbol # 2) of the (R−) PDSCH. As another example, at least some bits in the CIF field may indicate a difference (eg, an offset) from a reference position. For example, the reference position for designating the start position of the (R-) PDSCH is OFDM symbol # 2 (in this example, the offset is +1) or the start position of the R-PDCCH (in this example, the offset is − 1 applies). More specifically, the RRC signaled CFI is used to designate the start position of the R-PDCCH, and the CIF information of the DCI format is used to inform the difference between the R-PDCCH start symbol and the (R-) PDSCH start symbol. Can be.

If the CA is configured, a bit that is not used to specify the start position of the (R-) PDSCH in the CIF field is used to indicate a carrier to which the R-PDCCH is applied according to the original use. On the other hand, if the CA is not set, the bits that are not used to specify the starting position of the (R-) PDSCH in the CIF field may be used for other purposes, for example, the resource usage status of the second slot (e.g., whether the UL grant is present), or the like. Can be used to indicate.

In the above description, the start position of the R-PDCCH is fixed and the start position of the (R-) PDSCH is changed. However, the present invention is also applicable to the case where the start position of the (R-) PDSCH is fixed and the start position of the R-PDCCH is variable.

11 to 12 illustrate a method of notifying the start position of the R-PDCCH and the (R-) PDSCH start position using CIF. FIG. 11 illustrates a case in which the start position of the R-PDCCH and the (R-) PDSCH start position are independently given, and FIG. 12 illustrates a case in which the start position of the R-PDCCH and the (R-) PDSCH start position are equally limited. This scheme is basically the same as described with reference to FIG. 10 except that the location of the R-PDCCH is also changed using CIF.

The present scheme can be applied to different start positions of R-PDCCH for each carrier. To specify the start position of the R-PDCCH / (R-) PDSCH, all or some bits of the CIF field may be used. If the start position of the R-PDCCH / (R-) PDSCH cannot be freely designated by using only some bits of the CIF field, some bits of the CIF field may be used in combination with other values. For example, a start position of the R-PDCCH / (R-) PDSCH may be designated by combining some bits of the CIF field and a CFI value.

Equation 2 shows a case where a combination of CFI and CIF is used.

Here, fa and fb represent functions having CFI and CIF as arguments. fa and fb can be given differently or equally. For example, fa and fb may be in the form of CFI + Δa and CFI + Δb, respectively. In this case, Δa and Δb may mean difference values (offsets) determined by CIF values. CIFa and CIFb correspond to all or some bits of the CIF field. CIFa and CIFb may have different values or the same value. When CIFa and CIFb have different values, CIFa and CIFb may correspond to different bits of the CIF field, respectively.

For example, if only one bit can be used in the CIF field and only two symbol positions can be designated, the CIF information can be used for notifying only a difference value based on the RRC signaled CFI information for each carrier. .

In the above description, the scheduler transmits using only DCI formats including a CIF field when a CA is set in the backhaul link, and transmits using only DCI formats including a CIF field when a CA is not set. May be limited. If the CA is set, the above-described methods can be applied using a limited bit CIF. In the case of non-CA, CIF is not available, so the extra bits can be used for the previously presented method by reinterpreting the existing RA bits.

Meanwhile, the backhaul may be limited to always use the DCI format including the CIF regardless of CA. In this case, the entire non-CA CIF field may be used for other purposes. This can be configured to allow more free resource allocation and R-PDCCH multiplexing in non-CA mode.

13 to 14 illustrate a method of informing the R-PDCCH and / or (R-) PDSCH start position in a situation where a plurality of CCs are configured and there are a plurality of relays.

FIG. 13 illustrates a case in which CFI is independently designated for each CC, and R-PDCCH start positions of all RNs are set / fixed to the same position in the corresponding CC. When the start position of the R-PDCCH is fixed, the start position of the R-PDCCH may always be fixed at a specific symbol position or semi-statically. When semi-statically fixed, the starting position of the R-PDCCH may be semi-statically designated using the RRC CA CFI. On the other hand, in this example, the (R-) PDSCH start position of the RN may be set differently for each RN using CIF.

FIG. 13 assumes that two carriers are merged and two relays RN1 and RN2 use both CC # 1 and CC # 2. CFI is set independently for each CC and relays using each CC may be set differently, but for convenience, it is assumed that RN1 and RN2 use both CC # 1 and CC # 2. Each RN may set the RN PDCCH size (k = 1 or 2) differently. In addition, it is assumed that the RN PDCCH size may be set differently when CC is different from one relay. For example, as shown, the RN PDCCH size of RN1 in CC # 1 is 2, the RN PDCCH size of RN2 is 1, the RN PDCCH size of RN1 in CC # 2 is 1, and the RN PDCCH size of RN2 is 2 Can be given. In this case, the start position of the (R-) PDSCH in a specific CC may be indicated using all or some bits (eg, 1 bit) of the CIF field of the DCI format supporting the CC.

In particular, since the starting position of the R-PDCCH starting position and the (R-) PDSCH are almost the same, and there may be a general difference of only one symbol between them, the R-PDCCH starting position is used by using additional information of about 1 bit. A method of informing relative information about PDCCH may be used.

Here, Δ is indicated using 1 bit information of the CIF field.

For example, in the case of RN1 in CC # 2, it can be seen that the R-PDCCH start symbol is # 3 and the (R-) PDSCH start symbol is # 2, which is calculated by 2 = 3-1 (Δ = -1). do.

FIG. 14 illustrates a case in which a CFI is independently designated for each CC and an R-PDCCH start position of each RN may be set differently in the corresponding CC. The R-PDCCH start position of each RN may be independently set using an RRC signal or may be independently set using CFI and RN PDCCH symbol number for each CC. In addition, in this example, the (R-) PDSCH starting position of the RN may be set differently for each RN using CIF as shown in FIG. 13. This scheme is basically the same as FIG. 13 except that the R-PDCCH start position of each RN in the CC may be set differently, and thus, see FIG. 13 for details.

As another example, the following constraints may be further considered. This makes resource management easier.

(a) The same RN PDCCH size (that is, the number of OFDM symbols k) of all RNs using the CC for each CC is kept the same.

-RN1 = RN2 = k for each CC # i (i = 1, 2, 3 ...)

(b) The RN PDCCH size for each RN maintains the same value across all CCs.

-RN1 = k1 for all the CCs (CC # 1, CC # 2 ...)

-RN2 = k2 for all the CCs (CC # 1, CC # 2 ...

Although the above description has been described based on the relationship between the base station and the relay, the above description may be applied to the same / similarly to the relationship between the base station and the terminal, the relay and the terminal. For example, when applied to the relationship between the base station and the terminal, in the above description, the relay may be replaced with the terminal. In addition, when applied to the relationship between the relay and the terminal, in the above description, the base station may be replaced with a relay and the relay may be replaced with a terminal.

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

Referring to FIG. 15, a 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 a terminal may be connected to a base station.

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

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

In this document, embodiments of the present invention have been mainly described based on data transmission / reception relations between a terminal, a relay, and a base station. The specific operation described herein as being performed by the base station may be performed by its upper node, in some cases. That is, it is apparent 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 a network node other than the base station or the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. In addition, the terminal may be replaced with terms such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), and the like.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, 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, etc. that performs the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Industrial availability

The present invention relates to a wireless communication system, and specifically, may be applied to a base station, a relay, and a terminal.

Claims (14)

In the method for receiving a downlink signal in a wireless communication system,
Receiving a downlink control channel signal having a carrier indication field (CIF) and resource allocation information; And
Receiving a downlink shared channel signal from at least one resource block indicated by the resource allocation information in a subframe,
The start position of an Orthogonal Frequency Division Multiplexing (OFDM) symbol in which the downlink shared channel signal is present in the subframe is indicated using bit information of the CIF. The method of claim 1,
Some of the bit information of the CIF indicates a carrier in which the downlink shared channel signal exists, and the remaining of the bit information of the CIF indicates a start position of an OFDM symbol in which the downlink shared channel signal exists. How to. The method of claim 1,
Some of the bit information of the CIF indicates a resource usage state in the second slot of the subframe, and the remaining of the bit information of the CIF indicates the start position of an OFDM symbol in which the downlink shared channel signal is present. Characterized by the method. The method of claim 1,
The bit information of the CIF indicates a difference between a start position of an OFDM symbol in which a downlink control channel signal exists and a start position of an OFDM symbol in which the downlink shared channel signal exists in the subframe. . The method of claim 1,
And a start position of an OFDM symbol in which the downlink shared channel signal is present is indicated using bit information of the CIF and a control format indicator (CFI) value. The method of claim 1,
The CFI value is received using a Radio Resource Control (RRC) signal. The method of claim 1,
The downlink control channel signal is a relay physical downlink control channel (R-PDCCH) signal, the downlink shared channel signal is characterized in that the relay physical downlink shared channel (R-PDSCH) signal. A communication device configured to receive a downlink signal in a wireless communication system,
An RF (Radio Frequency) unit; And
Includes a microprocessor,
The microprocessor receives a downlink control channel signal having a carrier indication field (CIF) and resource allocation information, and receives a downlink shared channel signal from at least one resource block indicated by the resource allocation information in a subframe. Composed,
And a start position of an orthogonal frequency division multiplexing (OFDM) symbol in which the downlink shared channel signal is present in the subframe is indicated using bit information of the CIF. 9. The method of claim 8,
Some of the bit information of the CIF indicates a carrier in which the downlink shared channel signal exists, and the remaining of the bit information of the CIF indicates a start position of an OFDM symbol in which the downlink shared channel signal exists. Communication device. 9. The method of claim 8,
Some of the bit information of the CIF indicates a resource usage state in the second slot of the subframe, and the remaining of the bit information of the CIF indicates the start position of an OFDM symbol in which the downlink shared channel signal is present. Characterized in that the communication device. 9. The method of claim 8,
The bit information of the CIF indicates a difference between a start position of an OFDM symbol in which a downlink control channel signal exists and a start position of an OFDM symbol in which the downlink shared channel signal exists in the subframe. Device. 9. The method of claim 8,
And a start position of an OFDM symbol in which the downlink shared channel signal is present is indicated using bit information of the CIF and a control format indicator (CFI) value. 9. The method of claim 8,
Wherein the CFI value is received using a Radio Resource Control (RRC) signal. 9. The method of claim 8,
And the downlink control channel signal is a relay physical downlink control channel (R-PDCCH) signal, and the downlink shared channel signal is a relay physical downlink shared channel (R-PDSCH) signal.

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