KR20120000540A - Apparatus and method of resource allocation for channel in relay system - Google Patents

Abstract

PURPOSE: A device and a method of resource allocation for channel in a relay system are provided to effectively allocate the downlink backhaul subframe of a base station which is used fro transmitting a control information about the relay and a terminal. CONSTITUTION: A PRB(Physical Resource Block) area about an R-PDCCH(Relay-Physical Downlink Control CHannel) distinguishes a plurality of areas in a frequency area. The PRB information of each area is transmitted through a command R-PDCCH(common R-PDCCH). A plurality of domain frames about R-PDCCH is based on an PHICH(Physical Hybrid ARQ Indicator Channel). The R-PHICH is accepted in the PHICH based on the relay control area. The R-PHICH starts in a fifth symbol.

Description

Apparatus and method for allocating channel resource in relay system {APPARATUS AND METHOD OF RESOURCE ALLOCATION FOR CHANNEL IN RELAY SYSTEM}

The present invention relates to a relay system of an orthogonal frequency division multiple access (OFDMA) scheme, and more particularly, to transmit control information for a relay node (RN) and a user equipment (UE) in a relay system. The present invention relates to efficient resource allocation of a downlink backhaul subframe of an e-UTRAN NodeB (eNB).

 The present invention is derived from a study performed as part of the next generation communication network industrial source technology development project of the Ministry of Knowledge Economy. [Task management number: 10035300, Assignment name: Multi-hop Relay technology development].

Recently, communication standards for improving performance in terms of throughput, latency, and coverage have been developed in mobile communication systems. A widely used standard is the UMTS (Universal Mobile Telecommunications System) which was developed as part of the 3rd generation (3G) mobile communication system and is maintained by the 3rd Generation Partnership Project (3GPP). Among these, 3GPP Long Term Evolution (LTE) is a communication standard driven by 3GPP to achieve high data rate, low latency, packet optimized system performance and wide coverage in UMTS systems.

In LTE-Advanced (4th generation mobile communication) system, a signal transmission using a relay (RN) system as well as a direct communication method between a base station and a terminal in order to support a higher data rate and expand the serviceable coverage in a mobile communication system The method is being studied. This technology enables high-speed data communication by reducing the signal loss by relaying signals in the path between the base station and the terminal through a relay, and extends the service area by transmitting a signal to a mobile terminal far from the base station.

The relay of the LTE-Advanced mobile communication system is used for the purpose of eliminating the shadow area in the cell, and is installed in the cell boundary area to improve the effective cell coverage and throughput. The downlink physical layer signals transmitted from the base station to the terminal include a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), a physical control format indicator channel (PCFICH), and a physical hybrid ARQ indicator channel (PHICH). In addition, the uplink physical layer signal transmitted from the terminal to the base station includes a PUSCH (Physical Uplink Shared Channel), a PUCCH (Physical Uplink Control Channel), SRS (Sounding Reference Signal).

In an LTE-Advanced mobile communication system, a base station transmits a subframe including a signal for transmitting to a terminal through a downlink, and each subframe transmits a control channel for transmitting control information and transmits data. It consists of a data channel (data channel) for. In the case of a subframe of a downlink channel including information for transmission from a base station to a relay, it may be undesirable to allocate all of the subframes to transmission of information for relay. Accordingly, the base station can induce efficient resource utilization by allocating a channel for a mobile terminal and a channel for relay in an orthogonal frequency division multiple access (OFDM) scheme for one subframe in a downlink channel. In this case, it is necessary to allocate resources of the subframe of the downlink channel so that the information of the downlink channel transmitted from the base station can be correctly recognized by the relay and the terminal, and it is necessary to transmit and receive information through the allocated subframe.

An object of the present invention is to provide an apparatus and method for efficiently allocating resources of a downlink backhaul subframe of a base station used for transmitting control information for a relay and a terminal in a relay system.

According to an aspect of the present invention, an apparatus and method for efficiently allocating resources of a downlink backhaul subframe of a base station used for transmitting control information for a relay and a terminal in a relay system are disclosed. According to this apparatus and method, a transmission unit resource (PRB) region for an RN control channel (R-PDCCH) is divided into a plurality (for example, three) in the frequency domain, and PRB information of each region is divided into a common RN control channel ( Common R-PDCCH). At this time, three regions for each R-PDCCH are based on PHICH. As an example of the division, the PRB region for the R-PDCCH may be divided into three regions based on the PHICH in the frequency domain. In this case, the Common R-PDCCH may use three legs (REGs) as information that all RNs in the base station should simultaneously recognize. In addition, the common R-PDCCH is a channel to be recognized first in the backhaul subframe, and starts from a fixed position and is recognized without a special signal for the position. The PRB information included in the common R-PDCCH can be changed for every backhaul subframe.

According to the present invention, Dedicated R-PDCCH detection overhead of RN through full frequency diversity of backhaul resources and dynamic optimal allocation of resources to R-PDCCH through efficient common signals in FDM + TDM for backhaul resources of LTE system There is an advantage that can easily accommodate the reduction and future introduction of Mobile RN. It also has the advantage of providing effective backward compatibility.

1 illustrates the configuration of an exemplary relay system in which the present invention may be practiced.
2 illustrates an LTE DL frame structure.
3 illustrates an LTE UL frame structure.
4 illustrates the structure of a backhaul subframe for SI avoidance in a relay system;
5 is a diagram illustrating a PRB in a normal subframe type.
6A and 6B illustrate an FDM + TDM scheme and an FDM scheme in a backhaul subframe.
7 is a diagram illustrating a channel resource allocation process according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions will not be described in detail if they obscure the subject matter of the present invention.

1 is a diagram illustrating a configuration of an exemplary relay system in which the present invention may be implemented.

As shown in FIG. 1, the relay system includes a base station (eNB) 10, a relay (RN) 20, and a terminal (UE) 30.

The base station 10 may provide a communication service through a radio link to a relay region and a terminal 30 in a coverage region or a cell in which the base station 10 provides a network access service.

The relay 20 may be configured to replace a repeater, and a frequency band A used for a backhaul link between the base station 10 and the relay 20 is a link between the relay 20 and the terminal 30. The same band as the frequency band B used for the (access link) can be used. That is, the relay 20 may be an inband half-duplex relay in which the frequency band A and the frequency band B are the same and apply separate transmission / reception intervals in time. In addition, the relay 20 may be an outband relay having different frequency bands A and B.

The relay 20 includes a donor antenna for communicating with the base station 10 and a service antenna for communicating with the terminal 30, thereby communicating between the base station 10 and the terminal 30. It acts as a communications mediator. Since the relay 20 uses a wireless backhaul rather than a wired backhaul link, there is no need to add a new base station or install a wired backhaul.

The relay 20 receives a signal at a predetermined time and frequency from the base station 10 (/ terminal 30) at the time of downlink (uplink) and DL / UL at the received signal. After removing the SI component, it modulates according to the transmission structure and performs retransmission to the terminal 30 (/ base station 10).

The relay 20 is located anywhere within the coverage of the base station 10 via a wireless backhaul and is perceived as a base station eNB for the UE (Macro UE), while one for the base station 10. Recognized as a terminal (Macro UE), it is possible to extend the communication coverage area by relaying a signal between the base station 10 and the terminals (30a ~ 30c).

In general, since the base station 10 has a fixed position, the flexibility of the mobile communication network configuration is low, and thus, it is difficult to provide an efficient communication service in a wireless environment in which traffic distribution or call demand is severely changed. In order to overcome this disadvantage, the relay system is a fixed relay (fixed RN) (20a, 20c) fixedly located at one point, or a mobile relay (mobile RN) (20b) mounted on a train or bus, etc. By configuring the mobile communication network in a multi-hop manner, the communication service area of the relay system can be expanded and the system capacity can be increased. In addition, the relay 20 may be a Nomadic RN mounted on a vehicle to support eventful subscriber congestion.

As shown, the base station 10 transmits data directly or via a relay 20a to the terminals 30a, 30b included in the communication coverage area of the base station 10, and the communication coverage area of the base station 10. The terminal 30c, which is located outside and cannot directly communicate, transmits data through the relay 20c. In addition, since the terminal 30c located outside the communication coverage area of the base station 10 cannot directly communicate with the base station 10 due to the limitation of the transmission power, the terminal 30c transmits data to the base station 10 through the relay 20c.

Terminals 30a-30c may include any type of portable wireless communication device or system, including, for example, a mobile phone, a portable computer having a mobile communication function, a PDA having a mobile communication function, or another device. Although FIG. 1 illustrates that one base station 10 supports only three relays 20a to 20c and three terminals 30a to 30c, the base station 10 includes more or fewer relays and Note that the terminal may be supported.

Although not specifically illustrated, the relays 20a to 20c or the terminals 30a to 30c transmit signals to the base station 10 through an uplink channel, and the base station 10 may be a relay 20a to 20c or the terminal ( 30a to 30c) transmit a signal through a downlink channel. In particular, the subframe of the downlink channel including information transmitted from the base station 10 through the relays 20a to 20c includes a control channel and data for transmitting control information for the relays 20a to 20c. It is configured to include a data channel for transmission, a control channel for transmission of control information for the terminals 30a to 30c, and a data channel for transmission of data. Each control channel for the relays 20a to 20c and the terminals 30a to 30c is positioned in advance of the remaining data channels on the time axis. This is to allow the relays 20a to 20c and the terminals 30a to 30c to determine whether to perform the data channel reception operation by first receiving the control channel and recognizing whether or not the data channel transmitted to the relay channel is transmitted. Therefore, when the relay 20a to 20c and the terminal 30a to 30c determine that there is no data channel transmitted from the control channel, the relays 20a to 20c do not need to receive subsequent data channels. You can save.

The relays 20a to 20c will be described based on a Long Term Evolution (LTE) system using the OFDMA method.

The 3GPP LTE system defines multiple bandwidths, which are shown in Table 1 below.

LTE is a mobile communication system using the OFDMA scheme, and the transmission frame structure is shown in FIGS. 2 and 3. FIG. 2 is an LTE DL (DownLink) frame structure having a transmission bandwidth of 10 MHz, and FIG. 3 is an LTE UL (UpLink) frame structure having a transmission bandwidth of 10 MHz.

Referring to FIG. 2, the horizontal direction of the subframe represents the time axis and the vertical direction represents the frequency axis. The subframe includes a predetermined number of symbols along the time axis and spans a predetermined bandwidth along the frequency axis. Each region in the subframe represents a radio resource determined in the time and frequency domain.

The minimum transmission unit in the LTE DL frame structure is a transmission time interval (TTI). Each TTI (subframe) is composed of two consecutive slots (even-numbered slots and odd-numbered slots constitute 1TTI, that is, a pair of Physical Resource Blocks (PRBs)). Is done. One slot consists of 50 resource blocks (RBs). For example, one RB consists of a time axis of 7 symbols (l = 0, ... 6) and a frequency axis of 12 subcarriers. In this case, each RB consists of 84 resource elements (7x12 = 84). DL data transmission from the eNB to the UE is performed in units of RBs. In the LTE DL frame structure, DL data is transmitted through a physical downlink shared channel (PDSCH), and DL control information is transmitted through a physical downlink control channel (PDCCH), a physical control format indicator channel (PCFICH), and a physical hybrid ARQ indicator (PHICH). Channel). DL synchronization channels include a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH). In addition, RS is used as a signal for coherent detection and measurement of DL data and DL control information.

PCFICH is a physical channel for transmitting control format indicator (CFI) information. CFI is 2-bit length information indicating the number of OFDM symbols in which a PDCCH is located in a corresponding subframe. The UE must first receive the CFI to determine the number of OFDM symbols of the PDCCH as a ratio. Accordingly, the PCFICH is located at the first OFDM symbol position of the subframe so that the UE receiving the subframe can receive the PCFICH first of the subframes. The PCFICH is located over a plurality of divided regions in terms of frequency, thereby obtaining a gain due to frequency diversity.

The PDCCH is a control channel for transmitting information on allocation of a data channel to be received or information on power control. QPSK is commonly used as a modulation scheme for the PDCCH. When the channel coding rate is changed according to the channel state of the UE, the amount of resources used for the PDCCH may be changed. Therefore, a high channel coding rate may be applied to a UE having a good channel state to reduce the amount of resources used. On the other hand, even if the amount of resources used is increased for a UE having a poor channel state, the reception accuracy can be improved by applying a low channel coding rate.

PDSCH is a data channel for transmitting data delivered to a UE.

Although not shown in the figure, the subframes of the downlink channel may also include a relay node physical control format indicator channel (R-PCFICH) and a relay node physical downlink control channel (R-PDCCH), which are channels for control information for the RN in the eNB. It includes a relay node Physical Downlink Shared Channel (R-PDSCH), which is a channel for data for RN. R-PDCCH, R-PDSCH, and R-PDSCH are different only in that they are information for RN, respectively, and their functions and roles are similar to those of PCFICH, PDCCH, and PDSCH described above with respect to UE.

The R-PCFICH is a physical channel for transmitting relay control format indicator (R-CFI) information. R-CFI is information indicating the number of OFDM symbols used by the R-PDCCH, which is a control channel for an RN in an eNB. Since the accurate transmission of the R-CFI is very important in securing the stability of the mobile communication system, it is required to be transmitted using a code having a very low coding rate in order to minimize an error in the transmission process.

The R-PDCCH is a control channel for transmitting information on allocation of a data channel for RN or information on power control.

R-PDSCH is a data channel for transmitting data delivered to the RN.

Meanwhile, referring to FIG. 3 for better understanding, the definition of TTI, Slot, RB, and RE in the LTE UL frame structure is the same as in the LTE DL frame structure. In the LTE UL frame structure, UL data is transmitted through a PUSCH (Physical Uplink Shared Channel), and UL control information is performed through a PUCCH (Physical Uplink Control Channel). The SRS (Sounding Reference Signal) is used for UL channel measurement, and the SRS transmission position may be located at the last symbol (l = 6) of the second slot (odd-numbered slot) in the TTI. Shown). In addition, RS is used as a signal for coherent detection and measurement of UL data and UL control information.

Physical layer signals transmitted from uplink (UE to eNB) in LTE Release 8 include PUCCH, PUSCH, and SRS. PUCCH is a channel of a physical layer for transmitting an uplink control signal, and through this channel, uplink scheduling request information (SR), response information according to downlink data transmission (HARQ ACK / NACK), and channel quality information (CQI / PMI / RI) and the like are transmitted. PUSCH is mainly a physical channel for transmitting data of a UE, and when one UE needs to simultaneously transmit data and control signals, it is multiplexed and transmitted through this channel. The SRS is used for measuring timing information for measuring channel quality of uplink at the eNB or time synchronization between the eNB and the UE.

The wireless backhaul interface between the eNB and the RN is referred to as an "un interface (backhaul link)", and the access interface between the RN and the UE in the RN cell is referred to as an "access link". Also, in order to prevent self interference (SI) existing on the backhaul like a general wireless repeater, the RN on the Un interface performs a backhaul timing as shown in FIG. 4 to separate the time for data reception from the eNB and data transmission to the UE. MBSFN (MBMSN Single Frequency Network) subframe is used for backhaul timing to receive backhaul data from eNB, which is the CQI measurement error of Legacy UE. In order to avoid the problem, the cell specific reference signals (R0: ANT Port 0, R1: ANT Port 1, R2: ANT Port 2, R3: ANT Port 3) for each antenna port are placed in the control part where the first and second symbols are located. Transmit to access interval. In addition, the RN performs processing switching for data transmission on the backlink data reception and access link, and has a guard period of 1 ms or less therebetween to switch between data transmission and reception. Also, in order to effectively use DL backhaul subframes in 3GPP, FDM + TDM schemes and FDM schemes that simultaneously support DL data and control for the UE and RN for each backhaul subframe timing are considered.

Two types of subframes that can be used for the backhaul link discussed in 3GPP are defined. When the eNB does not support the MBMS service, the 'Normal subframe' is used, and when the eNB supports the MBMS service, the 'MBSFN subframe' is used for the backhaul link.

On the other hand, two schemes for multiplexing the R-PDCCH have been proposed. That is, as shown in FIG. 6A, PDSCH and RN data are multiplexed by frequency division multiplexing (FDM) and R-PDCCH and R-PDSCH are TDM (Time Division Multiplexing). 6F is divided into " FDM + TDM scheme " and " FDM scheme " using only FDM without TDM between R-PDCCH and R-PDSCH, unlike FDM + TDM as shown in FIG. 6B.

As shown in FIG. 6B, in the FDM scheme, the R-PDCCH and the R-PDSCH occupy the fourth to thirteenth symbols in the same time domain, and the R-PDCCH and the R-PDSCH correspond to the frequency domain. multiplexed in the frequency domain). That is, the eNB semi-statistically sets a PRB set that can be used as an R-PDCCH through a higher layer and transmits it to all RNs through an R-PDSCH, and when a change is required, an R-PDSCH to an individual RN. Transmit each. It is easy to apply pre-coding of R-PDCCH through DMRS (Demodulation Reference Signal), but there are two REGs in the symbol where CRS is located and three REGs in the symbol where CRS is not located, as shown in FIG. As a result, a total of 29 REGs exist in a pair of PRBs. Therefore, in case of legacy, the minimum CCE size for One PDCCH is composed of 9REGs, and the new definition of interleaving and RE mapping rule for R-PDCCH will be required, due to the size of single R-PDCCH larger than FDM + TDM. It can be a waste of resources. In addition, it is easy to support frequency selectivity scheduling due to the nature of FDM, but it is required to reset R-PDCCH semi-statistically and re-signal for not only the introduction and release of new RN but also the best frequency change for individual RN. May cause collisions with frequency selectivity scheduling for the UE. If the RN PRB region is defined to reduce the blind detection overhead of the RN's R-PDCCH, resetting may be required for each change of the RN's position, or the frequency diversity effect may be degraded. In order to increase R-PDCCH for a plurality of RNs in a pair of PRBs, blind detection overhead may be increased.

As shown in FIG. 6A, in the case of FDM + TDM, the fourth to seventh symbols in the time domain are defined as the regions of the R-PDCCH, and the resource allocation for the R-PDCCH in the frequency domain is the same as that of the FDM. In a pair of PRBs, a second slot consecutively formed in a semi-statistically-configured R-PDCCH is defined as a normal R-PDSCH.In case of insufficient resources for the R-PDSCH, the fourth to 13th symbols of the pair of PRBs are insufficient. It is defined as Extend R-PDSCH using. Of course, when assigning two types, a separate identifier is not required because all RNs recognize the PRB set previously allocated for the R-PDCCH. If semi-statistically allocated R-PDCCH is not used, the entire pair of PRBs are allocated for the PDSCH, and the interleaving is performed only in one PRB by defining the CCE size as 11 REG. The same R-PDCCH is duplicated in another PRB region semi-statistically set according to the aggregation level. In addition, when introducing and releasing a new RN, the PRB for the R-PDCCH needs to be reset and re-signaled in the upper layer semi-statistically in the frequency domain.

In both methods, an effective new rule for R-PDCCH blind detection should be defined. Particularly, the present invention focuses on the method for full frequency diversity and effective detection of blind detection for the effective R-PDCCH, dynamic allocation of the size of the R-PDCCH region and effective transmission of information on the R-PDCCH region in FDM + TDM. have.

In FDM + TDM, the eNB must inform all RNs of the R-PDCCH region semi-statistically and re-notify when a change is necessary. Therefore, in order to reduce overhead for re-notification, it is necessary to avoid resetting and re-notification at the time of new RN through sufficient R-PDCCH allocation from the beginning. will increase the number of detections. In this case, it is possible to avoid resetting the PRB set for some R-PDCCH under the assumption that all the RNs of the donor cell are fixed and the channel environment hardly changes.However, if the mobile / Nomadic RN is assumed, the PRB set can be avoided. May cause significant waste of R-PDSCH resources for reconfiguration. In addition, in the case of interleaving, the interleaving effect is deteriorated because it must be interleaved only within one PRB. When the CCE size of the R-PDCCH is not defined as 11 REGs included in the One PRB, the interleaving blinds the R-PDCCH of the RN due to the interleaving size problem. May cause decoding overhead. In addition, since the R-PDCCH having a low aggregation level is only mapped to the One PRB, it is expected to reduce the frequency diversity effect, and it may not be easy to include the R-PHICH for hybrid ACK / NACK for the UL R-PDSCH. To this end, instead of R-PHICH, transmission of Nack through R-PDCCH for UL grant may be used. However, in this case, when the Mobile RN and the backhaul CQI are unstable, NACK for the UL R-PDSCH will frequently occur, and resource consumption of the R-PDCCH is expected by signaling an unnecessary R-PDCCH for feedback.

FIG. 7 is a diagram illustrating a channel resource allocation process according to an embodiment of the present invention and shows a PHICH-based multi R-PDCCH region allocation process.

An apparatus for allocating channel resources of an eNB according to the present invention divides a transmission unit resource (PRB) region for an RN control channel (R-PDCCH) into a plurality (eg, three) in a frequency domain, and divides PRB information of each region. Transmit through common RN control channel (Common R-PDCCH). At this time, three regions for each R-PDCCH are based on PHICH.

As an example of the division, the PRB region for the R-PDCCH may be divided into three regions based on the PHICH in the frequency domain. In this case, the Common R-PDCCH may use three legs (REGs) as information that all RNs in the base station should simultaneously recognize. In addition, the common R-PDCCH is a channel to be recognized first in the backhaul subframe, and starts from a fixed position and is recognized without a special signal for the position. The PRB information included in the common R-PDCCH can be changed for every backhaul subframe.

The divided area may be treated as one logically continuous area during interleaving.

In one embodiment, the PRB information includes dynamic R-PDCCH size and PRB set information. In another embodiment, the number of PRBs, number of R-PHICH groups, and paging information for each region of the R-PDCCH is included.

In detail, in FIG. 7, in the case of legacy, that is, eNB, a corresponding PHICH is overlapped with REGs of three specific PRBs by bandwidth and PCI. Also, additional REGs are consumed in each region by the number of PHICH groups. Therefore, the RN can know the bandwidth and PCI of the eNB in advance so that they can know their location. Based on this, the PRB region for the R-PDCCH is divided into three regions based on the three PRBs for the PHICH in terms of frequency, and indicates the PRB size of each region through the Common R-PDCCH. However, the three regions can achieve the effect of full frequency diversity by performing interleaving by recognizing them as logically continuous regions during R-PDCCH interleaving, and using the same dedicated RN-RNTI based search space rule as in the legacy scheme. By applying this, effective blind detection for R-PDCCH can be achieved.

As a result, explicit signaling for the PRB set for the R-PDCCH is not required, thereby increasing the utilization of the R-PDSCH. Of course, the resource consumption for the separate Common R-PDCCH and the condition that the RN must decode the Common R-PDCCH before the detection of the dedicated R-PDCCH, but the resource for the Common R-PDCCH is 3 REGs as shown in FIG. As a result, resource consumption is not a problem as compared to the case of using R-PDSCH, and since decoding for the common R-PDCCH is also simple block coding based on BPSK, it can be ignored in terms of latency. Common R-PDCCH is a new channel that delivers information that all RNs should recognize simultaneously under one donor. Dynamic R-PDCCH size and PRB set information are reduced to reduce overhead caused by semi-statistic R-PDCCH by higher layer. Allows you to pass That is, the information included in the common R-PDCCH can be changed in every backhaul subframe, and the common R-PDCCH is a channel that all RNs should first recognize in the backhaul subframe and should always start at a fixed position. It should be recognized without special signal. As a result, when a change in the size of the R-PDCCH PRB set is required, the change can be notified dynamically without transmission through the individual R-PDSCH. The channel is based on the PHICH location. In addition, by processing three separate R-PDCCH regions as one logical region, it is easy to remove dependency on the CCE size of R-PDCCH, acquire full frequency diversity, accommodate the number of blind detects and relay control region of RN. Done. That is, R-PHICH starts at the fifth symbol and, unlike legacy, uses QPSK modulation.

The DL backhaul subframe excludes a subframe for paging and a subframe for transmitting System Information Blocks (SIB) 1, so that there is no way for the RN to recognize when a change occurs in the SIB of the eNB. That is, in case of legacy, the SIB change transmits paging and recognizes the changed SIB through the value tag of SIB1 in the next modification period, and reads the changed SIB based on the scheduling information. However, the eNB cannot perform paging transmission because the DL backhaul subframe does not allow paging, and even if receiving the paging, the eNB cannot receive DL subframe # 5 mapped to SIB1, so it is impossible to recognize the SIB change of the conventional scheme. Therefore, the changed contents are individually transmitted through dedicated R-PDSCH or common R-PDSCH based on common search space is indicated through information instead of paging on Common R-PDCCH to signal all RNs with one R-PDSCH. By indicating whether the common search space is applied, processing overhead can be reduced by performing blind decoding through common and dedicated search spaces only when the RN is requested.

A more detailed look at the Common R-PDCCH is as follows.

1. Obtain information of Common R-PDCCH

Common R-PDCCH specifies the number of PRBs, the number of R-PHICH groups, and paging for each of three R-PDCCH regions. The total number of PRBs available for the P-PDCCH is "100/3 = 33 PRBs" available in each region at maximum, which can be expressed in 6 bits. The three areas are the same size or differ by 1 PRB. Therefore, to specify this, a 2-bit extension is added, and a maximum of 30 RNs that can be accommodated in one eNB is considered in 3GPP. Therefore, assuming 4 R-PHICH groups, BPSK modulation is performed on "2 bits (paging) + 6 bits (33 PRB) + 2 bits (1PRB difference per sub region) + 2 bits (number of R-PHICH groups) = 12 bits". And 3 repetition to map to the RE of the Common R-PDCCH location. For example, if 100 PRBs are expected to be consumed as R-PDCCH in all specific backhaul subframes and 4 R-PHICH groups and paging are required, real data consists of "11" + "100001" + "01" + "11". do. That is, it is specified that all three areas are 33 PRBs, and only the last area is allocated 1 PRB.

If the 2bits (1PRB difference exists per sub region) are specified in detail, the corresponding bits are designated as "00" / "01" / "11" when the 9/10/11 PRB is expected as an R-PDCCH.

2. Detection of PRB number and location of R-PHICH for each region through Common R-PDCCH

Recognizing the number of PRBs for each of the three regions, the RN recognizes three regions as logically contiguous PRB regions, and the 3 REGs for the Common R-PDCCH itself and the number of R-PHICH groups through the number of R-PHICH groups. It performs CCE numbering based on CCE size with REGs except REGs and REGs for CRS, and performs blind detection like legacy UE by RN dedicated specific space based on RN-RNTI to recognize its dedicated R-PDCCH. .

If paging is indicated, the channel coding information and the PRB number for the Common R-PDCSH are recognized through non-blind decoding at fixed aggregation level 2 up to the highest CCE 0-2, similar to legacy.

3. R-PHICH recognition

If waiting for ACK / NACK by UL backhaul data transmission in previous UL backhaul subframe, it detects its ACK / NACK based on its Group ID and UL grant and Orthogonal sequences for its R-PHICH like legacy UE. detection

4. Acknowledgment of the change of the number of PRBs for each area through Common R-PDCCH

When introducing and releasing a new RN or changing the number of PRBs for the R-PDCCH by the RN active UE, the eNB dynamically signals the appropriate content of the Common R-PDCCH in every DL backhaul subframe, and all RNs always recognize this. can do.

5. If 2 slots are not allocated to the R-PDSCH in a pair of PRBs including the Common R-PDCCH, that is, if the required resources for the R-PDSCH are smaller than those of the R-PDCCH, only the REL-10 UE is assigned to the PRB. By allocating resources to reduce waste. In the opposite case, the R-PDSCH is mapped to the PDSCH region.

Although the method has been described through specific embodiments, the method may also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

While the invention has been described in connection with some embodiments herein, it should be understood that various modifications and changes can be made without departing from the spirit and scope of the invention as would be understood by those skilled in the art. something to do. Also, such modifications and variations are intended to fall within the scope of the claims appended hereto.

10: base station (eNB) 20a to 20c: relay (RN)
30a ~ 30c: UE

Claims (17)

A resource allocation device for a channel,
Channel resource allocation for dividing a plurality of transmission unit resource (PRB) regions for a relay control channel (R-PDCCH) from the frequency domain and transmitting PRB information of each region through a common relay control channel (Common R-PDCCH) Device. The method of claim 1,
And a plurality of regions for the R-PDCCH are based on PHICH (Physical Hybrid ARQ Indicator Channel). The method of claim 2,
And receiving a relay PHICH (R-PHICH) in a relay control region based on the PHICH, wherein the R-PHICH starts at a fifth symbol. The method of claim 2,
The division divides the PRB region for the R-PDCCH into three regions in the frequency domain based on the PHICH. The method of claim 4, wherein
The Common R-PDCCH is a channel that all relays in a base station should simultaneously recognize, and uses three legs (REGs). The method of claim 1,
A channel resource allocation apparatus for processing each area into one logically continuous area upon interleaving. The method of claim 1,
The PRB information includes a dynamic R-PDCCH size and PRB set information. The method of claim 7, wherein
The Common R-PDCCH is a channel that all relays in the base station should recognize at the same time and first recognize in the backhaul subframe.
The PRB information included in the common R-PDCCH is changeable in every backhaul subframe. The method of claim 1,
The PRB information includes a PRB number, an R-PHICH group number, and paging information for each region of the R-PDCCH. The method of claim 1,
The Common R-PDCCH, when changing the System Information Blocks (SIB) of the base station, the channel resource allocation apparatus including information for notifying the change. 10. The method of claim 9,
The common R-PDCCH includes information indicating whether to apply a common search space, and indicates whether a common R-PDCCH based on the common search space is present through information instead of paging to indicate one R-. Channel resource allocation apparatus for transmitting to all relays by PDSCH. A channel resource allocation method of a relay system,
Dividing a transmission unit resource (PRB) region for a relay control channel (R-PDCCH) into a plurality in a frequency domain; And
And transmitting PRB information of each region through a common relay control channel (Common R-PDCCH). The method of claim 12,
The plurality of regions for the R-PDCCH are based on PHICH (Physical Hybrid ARQ Indicator Channel),
The division is to divide the PRB region for the R-PDCCH into three regions based on the PHICH in the frequency domain,
The Common R-PDCCH is a channel that all relays in a base station should simultaneously recognize, and uses three legs (REGs). The method of claim 12,
When interleaving, each area is treated as one logically contiguous area. The method of claim 12,
The PRB information includes dynamic R-PDCCH size and PRB set information, and can be changed every backhaul subframe.
The Common R-PDCCH is a channel that all relays in a base station must simultaneously recognize and first recognize in a backhaul subframe. The common R-PDCCH starts at a fixed position and is recognized without a special signal for the position. The method of claim 12,
The resource for the Common R-PDCCH uses 3 REGs, and the Common R-PDCCH uses BPSK-based simple block coding. The method of claim 12,
The PRB information includes a PRB number, an R-PHICH group number, and paging information for each region of the R-PDCCH.

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