KR20130038784A - Method for transmitting control channel and relay system for the same - Google Patents

Abstract

PURPOSE: A control channel transmitting method and a relay system for the same are provided to increase capacity of a RN physical downlink control channel(R-PDCCH) in a relay node(RN) backhaul link and to manage radio resources. CONSTITUTION: A base station allocates a resource block(RB) for transmission to a physical resource block(PRB) associated with a relay node physical control channel(R-PDCCH) in a downlink sub-frame by dividing the PRB into the RB on a frequency domain. The base station allocates a relay node physical downlink shared channel(R-PDSCH) for transmission to an RB to which an R-PDCCH is not allocated. The information about R-PDCCH is transmitted by an upper layer message along with the information about a transmission mode and an antenna port. A first slot transmits an R-PDCCH through antenna port seven and eight, and a second slot transmits R-PDSCH through the antenna port seven and eight. The first slot allocates OFDM(Orthogonal Frequency-Division Multiplexing) symbols to the R-PDCCH domain by TDM+FDM allocation, which is a method allocating symbols on a time domain and RB on a frequency domain, not allocating only by TDM allocation, thereby increasing transmission capacity of the slot.

Description

Control channel transmission method and relay system therefor {METHOD FOR TRANSMITTING CONTROL CHANNEL AND RELAY SYSTEM FOR THE SAME}

The present invention relates to a relay system of an orthogonal frequency division multiple access (OFDMA) scheme, and more particularly, to improve the capacity of an RN control channel (R-PDCCH) in a relay node (RN) backhaul link. The present invention relates to a control channel transmission method.

 "This study was carried out as a result of the study of the original technology development project of the next generation communication network of the Korea Communications Commission" (KCA-2011-10913-04002)

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 to solve the shadow area in the cell, and it is installed in the cell boundary area and is used to improve the effective cell coverage expansion 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.

US 8,005,039 (registered August 23, 2011)

An object of the present invention is to provide a control channel transmission method and a relay system therefor that can improve the capacity of an RN control channel (R-PDCCH) in a relay (RN) backhaul link.

According to an aspect of the present invention, a control channel transmission method and a relay system therefor that can improve the capacity of the RN control channel (R-PDCCH) in the relay backhaullink is disclosed. According to the present invention, the base station first allocates a transmission unit resource (PRB) region for a relay control channel (R-PDCCH) on a downlink subframe in RB (Resource Block) units on a frequency axis or in an OFDM symbol unit on a time axis Second allocation, and transmits transmission mode and antenna port information. The relay blind-decodes the R-PDCCH using the transmission mode and the antenna port information to demodulate the data according to the R-PDSCH scheduling information.

In this case, the relay data channel (R-PDSCH) is allocated to a transmission unit resource (PRB) region in which the relay control channel is not allocated at the first allocation, or for the R-PDCCH of each relay for each layer during the second allocation. Allocate a transmission unit resource zone differently.

According to the present invention, there is an advantage in that the capacity of the relay control channel can be increased and resources can be saved by preventing waste of radio resources.

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 showing an example of transmission of an R-PDCCH and an R-PDSCH in the backhaul subframe (in the case of normal CP).
6A illustrates a transmission pattern based on CRS.
6B is a diagram showing a transmission pattern based on DM-RS.
7 is a diagram illustrating a transmission scheme of an R-PDCCH and an R-PDSCH in transmission mode 8;
8A is a diagram illustrating a control channel (R-PDCCH) transmission process of FIG. 7A according to an embodiment of the present invention.
8b illustrates a control channel (R-PDCCH) transmission process of FIG. 7 (b) 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 over a wireless link to a relay station 20 and a terminal 30 in a coverage region or cell where the base station 10 provides a network access service.

The relay 20 is located between the base station 10 and the terminal 30 to relay data from the base station 10 to the terminal 30 or the terminal 30 to the base station 10. In 3GPP, the communication between the base station 10 and the relay 20 is an "Un link" or a "relay backhaul link", and the communication between the relay 20 and the terminal 30 is a "Uu link" or " Access link ". Here, the base station connected to the relay 20 is called a DeNB (Donor eNB).

Relay 20 can be configured to replace a repeater (repeater), the frequency band A used for the link (Un-link or relay backhaul link) between the base station 10 and the relay 20 is the relay 20 and the terminal ( 30) The same band as the frequency band B used for the inter link (Uu link or access link) may be used. That is, the relay 20 may be an in-band relay in which the frequency band A and the frequency band B are the same and apply separate transmission / reception intervals in time. The relay 20 may also be an outband relay in which the frequency band A and the frequency band B are different. When the same frequency is used on the Un link and the Uu link (that is, when the frequency band A and the frequency band B are the same), they are defined as Type 1 relays. In type 1 relay, since self-interference occurs between transmitter and receiver, Un link and Uu links operate in half-duplex method using different time resources (subframes). That is, a time interval in which the base station 10 and the relay 20 communicate with each other through an un link is called a backhaul subframe. Detailed description of the backhaul subframe will be described later.

The relay 20 includes a donor antenna for communicating with the base station 10 and a service antenna for communicating with the terminal 30. The relay 20 includes a base station 10 and a terminal 30, It acts as a communication arbiter. The relay 20 uses a wireless backhaul instead of a wired backhaul link, so 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) in a downlink (/ uplink) And then retransmits the signal to the terminal 30 (/ base station 10) by modulating it according to the transmission structure.

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 is fixed in position, flexibility in the configuration of the mobile communication network is low. Therefore, it is difficult to provide an efficient communication service in a wireless environment where the traffic distribution and the call demand change are severe. 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. The relay 20 may also be a Nomadic RN mounted on the vehicle to support eventful subscriber congestion.

The base station 10 transmits data to the terminals 30a and 30b included in the communication coverage area of the base station 10 either directly or via the relay 20a, And transmits the data through the relay 20c to the terminal 30c which can not communicate directly. The terminal 30c located outside the communication coverage area of the base station 10 can not directly communicate with the base station 10 due to the restriction of transmission power and therefore transmits data to the base station 10 through the relay 20c.

The terminals 30a-30c may comprise any type of portable wireless communication device or system including, for example, a cell phone, a portable computer having mobile communication capabilities, a PDA or other device having mobile communication capabilities. 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 shown in detail, the relays 20a to 20c or the terminals 30a to 30c transmit signals through the uplink channel to the base station 10 and the base station 10 transmits signals through the relays 20a to 20c or the terminal 30a to 30c through the downlink channel. In particular, a subframe of the downlink channel including information transmitted from the base station 10 through the relays 20a to 20c includes a control channel for transmitting control information for the relays 20a to 20c, 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 of the control channels for the relays 20a to 20c and the terminals 30a to 30c is located before the remaining data channels on the time axis. This is for the purpose of determining whether the relays 20a to 20c and the terminals 30a to 30c preferentially receive a control channel and perform a data channel receiving operation by recognizing whether or not the data channel transmitted thereto is transmitted. Accordingly, when each of the relays 20a to 20c and the terminals 30a to 30c determines that there is no data channel to be transmitted from the control channel to itself, it is not necessary to receive the subsequent data channel, 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. A subframe includes a predetermined number of symbols along the time axis and spans a predetermined bandwidth along the frequency axis. Each area in a 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) consists of two consecutive slots (even-numbered slots and odd-numbered slots constitute 1TTI, that is, a Physical Resource Block (PRB)). One slot consists of 50 resource blocks (RBs). For example, one RB is composed of 7 time-axis symbols (l = 0, ... 6) and 12 frequency subcarriers. In this case, each RB consists of 84 resource elements (7x12 = 84). DL data transmission from the base station 10 to the terminal 30 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 terminal 30 receiving the subframe can receive the PCFICH for the first time among 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 thereafter, information on power control, and the like. QPSK is typically used as the modulation scheme for the PDCCH. If the channel coding rate is changed according to the channel state of the UE, the amount of resources used for the PDCCH can be changed. Therefore, a high channel coding rate can be applied to the terminal 30 having a good channel state, thereby reducing the amount of resources used. On the other hand, for the terminal 30 having a poor channel state, even if the amount of resources used is increased, the reception accuracy can be improved by applying a low channel coding rate.

The PDSCH is a data channel for transmitting data to the terminal 30. [

Although not shown in the figure, a subframe of a downlink channel is also a relay node Physical Control Format Indicator Channel (R-PCFICH) and a relay node (R-PDCCH), which are channels related to control information for the relay 20 in the base station 10. Relay Node Physical Downlink Shared Channel (R-PDSCH), which is a channel related to data for the physical downlink control channel) and the relay 20. The R-PDCCH, R-PDSCH and R-PDSCH are different only in that they are information for the relay 20, respectively, and their functions and roles are similar to those of the PCFICH, PDCCH, and PDSCH described above with respect to the terminal 30.

The R-PCFICH is a physical channel for transmitting relay control format indicator (R-CFI) information. The R-CFI is information indicating the number of OFDM symbols used by the R-PDCCH, which is a control channel for the relay 20 in the base station 10. 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 the relay 20 or information on power control.

The R-PDSCH is a data channel for transmitting data delivered to the relay 20.

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. The PUCCH is a physical layer channel for transmitting an uplink control signal, and includes uplink scheduling request information (SR), response information (HARQ ACK / NACK) based on downlink data transmission, and channel quality information (CQI / PMI / RI) are transmitted. The PUSCH is a physical channel for transmitting data of the UE, and when a single terminal 30 needs to simultaneously transmit data and a control signal, the PUSCH is multiplexed and transmitted through the channel. The SRS is used to measure uplink channel quality at the base station 10 or to measure timing information for time synchronization between the base station 10 and the terminal 30.

The backhaul subframe transmitted through the Un link will now be described in detail. 4 shows how the Tape 1 relay operates.

In the backhaul subframe as shown in the right subframe of FIG. 4, the control channel and the data channel may be received by the base station 10 only during the “transmission gap”. However, in the first two OFDM symbol intervals, a common reference signal (CRS) is transmitted for the terminals 30 connected to the relay 20. In the left subframe of FIG. 4, only control and data signal transmission are performed from the relay 20 to the terminal 30. In this time interval, the relay 20 does not receive any signal from the base station 10. The relay 20 allocates Uu subframes corresponding to the backhaul subframes to the Multimedia Broadcast over Single Frequency Network (MBSFN) subframes during the backhaul subframe to receive a signal on the Un link. The relay 20 may transmit a control and data channel to the terminal 30 in a subframe not designated as an MBSFN subframe.

The base station 30 transmits an R-PDCCH and an R-PDSCH for the relay 20 in an undownlink backhaul subframe period. The R-PDCCH is a control channel for the relay 20. The R-PDCCH transmits scheduling information on the R-PDSCH (R-PUSCH in the uplink) to the relay 20, and transmits information on the R-PDSCH to a downlink grant (DL). The information on the R-PUSCH is called an UL grant. The R-PDSCH is used for traffic transmission on the data channel for the relay 20. As shown in FIG. 5, R-PDCCH transmission is performed in the time domain from the third OFDM symbol of the first slot to the last OFDM symbol of the second slot on the time axis, and is performed within a virtual system bandwidth in PRB units on the frequency axis. In the R-PDCCH transmission region, the first slot is used for the DL grant, the second slot is used for the UL grant. The R-PDSCH is transmitted in the time-frequency domain in which the R-PDCCH is not transmitted.

The base station 10 informs the R-PDCCH transmission region (virtual system bandwidth) of each relay 20 through an upper layer message (for example, RRC (Radio Resource Control) message), the relay 20 in the R-PDCCH transmission region When blind decoding is performed and its R-PDCCH is demodulated, data is decoded using R-PDSCH scheduling information (information on PRBs used to transmit the R-PDSCH).

The R-PDCCH transmission mode includes a transmit diversity scheme and a transmission mode 8/9 scheme. Transmit diversity is also used for the PDCCH, and SFBC (2tx) or SFBC + FSTD (4tx) scheme is used depending on the number of base station antennas. Transmission modes 8 and 9 are beamforming transmission modes. When used for R-PDCCH transmission, transmission layers 8/9 can transmit one layer. However, when used for R-PDSCH transmission, two layer transmission is possible in transmission mode 8, and up to 4 layer transmission is possible in transmission mode 9. When the R-PDCCH is transmitted in the transmit diversity scheme, the R-PDCCH demodulation uses CRS, and in the transmission mode 8/9, demodulates using a DM-RS (Demodulation Reference Signal). The CRS has a transmission pattern as shown in FIG. 6A in one PRB, and is transmitted in the same pattern in the system bandwidth of a PRB unit. In addition, the DM-RS is present in one PRB in a pattern as shown in FIG. 6B, and exists only in PRBs allocated for the relay 20.

7 shows a method of transmitting an R-PDCCH / R-PDSCH in transmission mode 8.

In transmission mode 8, two layers may be transmitted using two antenna ports. According to 3GPP TS 36.216, the R-PDCCH may be transmitted using only antenna port 7.

First, when the R-PDCCH is transmitted in the first slot and the R-PDSCH is transmitted in the second slot, as shown in (a) of FIG. 7, the R-PDSCH transmission is performed using the antenna port 8 in the second slot. In the first slot, since R-PDSCH transmission is not performed using antenna port 8, radio resources may be wasted.

In addition, when only the R-PDCCH is transmitted in the first and second slots as shown in (b), radio resources may be wasted because the R-PDSCH is not transmitted using the antenna port 8 in both slots. Therefore, as more PRBs are allocated for R-PDCCH transmission, more radio resources may be wasted. This limits the number of R-PDCCHs that can be transmitted in the backhaul link, and requires a lot of radio resources for the R-PDCCH and thus cannot allocate many PRBs for R-PDSCH transmission. As a result, the performance of the backhaul link may be degraded, and thus, the base station 10 may not accommodate many relays 20.

When only the R-PDSCH is transmitted in the first and second slots as shown in (c), R-PDSCH transmission is performed using antenna port 8 in the first and second slots.

As described above, when the R-PDCCH and the R-PDSCH are transmitted using the DM-RS based transmission mode in the backhaul link, the R-PDCCH capacity and the performance of the backhaul link may be reduced due to waste of radio resources.

8A and 8B illustrate a control channel (R-PDCCH) transmission process of FIGS. 7A and 7B according to an embodiment of the present invention.

In the present invention, to solve the waste of radio resources generated when transmitting the R-PDCCH / R-PDSCH. Here, the transmission mode for the R-PDCCH uses transmission mode 8, and the antenna ports used for the transmission mode are ANT Ports 7 and 8.

The base station 10 transmits R-PDCCH transmission mode (transmission 8), antenna port information (antenna ports {7}, {8}, {7,8}), and R-PDSCH to each relay 20 through an upper layer message. It informs about the mode related to the transmission mode (LTE transmission mode 8 or 9), antenna port related information, information on the R-PDDCCH region (OFDM symbol number and RB number, etc.). In one embodiment, the higher layer message may be a Radio Resource Control (RRC) message. The scheme through the RRC message may be performed using a cell common message and / or a dedicated message. The transmission mode and antenna port related information (R-PDCCH transmission mode, antenna port information, R-PDSCH transmission mode, etc.) transmitted once are semi-static in nature, and the base station 10 changes the channel state or is in the cell. In consideration of the number of UEs, a transmission mode, antenna port related information, and R-PDCCH region information may be changed.

The base station 10 transmits the R-PDCCH as shown in FIGS. 8A and 8B based on the set transmission mode and the antenna port related information. In addition, R-PDSCH is transmitted to radio resources (PRBs) that are not used as R-PDCCH. The R-PDCCH is allocated and transmitted in units of RBs on the frequency axis, and the R-PDSCH is allocated and transmitted to the RBs to which the R-PDCCH is not allocated. Information about the R-PDDCCH region (such as the number of OFDM symbols and the number of RBs) is transmitted through an upper layer message along with transmission mode and antenna port related information.

As shown in FIG. 8A, the first slot transmits the R-PDCCH using antenna ports 7, 8, and the second slot transmits the R-PDSCH using antenna ports 7, 8. That is, the R-PDCCH and R-PDSCH of the first slot of layer 0 are transmitted through antenna port 7, and the R-PDCCH and R-PDSCH of the first slot of layer 1 are antenna port 8 Is sent through. In addition, the R-PDSCH of the second slot of layer 0 is transmitted through antenna port 7, and the R-PDSCH of the second slot of layer 1 is transmitted through antenna port 8.

In the first slot of FIG. 8A, the TDM + FDM allocation scheme (hybrid allocation scheme) is used to allocate the entire OFDM symbol (8 symbols) to the R-PDCCH region using the TDM allocation scheme, instead of the symbols of the time axis and the RB unit of the frequency axis. ), The capacity of the channel can be increased by allocating to the R-PDCCH region through antenna ports 7, 8. In addition, the capacity of the channel can be increased by transmitting the R-PDSCH using antenna ports 7, 8 for radio resources (PRBs) not used as R-PDCCH in the first slot. Meanwhile, the second slot transmits the R-PDSCH using antenna ports 7, 8.

Here, only one R-PDCCH for one relay 20 should exist in one PRB.

Therefore, when the R-PDCCH is transmitted to a specific RB of the first slot through the antenna port 7 and the R-PDSCH is transmitted to the second slot, the R-PDCCH is transmitted to the specific RB of the first slot through the antenna port 8 The R-PDSCH may be transmitted in the second slot. However, R-PDSCH is transmitted to radio resources (PRBs) not used as R-PDCCH in the first slot.

In one embodiment, the base station 10 may multiplex the R-PDCCH and the R-PDSCH according to the transmission mode and the antenna port related information.

The relay 20 blindly decodes the R-PDCCH using the transmission mode and the antenna port related information received through the higher layer message, and demodulates the data according to the R-PDSCH scheduling information when the R-PDCCH is present.

As illustrated in FIG. 8B, the entire OFDM symbol (for example, 16 symbols) of the first and second slots may be transmitted to the R-PDCCH using the antenna port 7. This method may be referred to as a TDM allocation method. In the TDM allocation scheme, the capacity of the control channel can be increased by extending the region of the R-PDCCH in units of OFDM symbols. In this case, the R-PDCCH associated with relay # 1 (for example 20-1) is transmitted through antenna port 8 (layer 1), and the R-PDCCH associated with relay # 2 (for example 20-2) is antenna port 7 (layer 0). ) Can be sent. That is, the control channel (R-PDCCH) for each relay may be transmitted for each antenna port. The relay 20 blindly decodes the R-PDCCH using the transmission antenna port information received through the upper layer message (RRC message), and then demodulates the data according to the R-PDSCH scheduling information when the R-PDCCH is present. .

In the above, a downlink grant message and an uplink grant message may be delivered to the R-PDCCH 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. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the above embodiments can be easily deduced by programmers of the present invention.

Although the present invention has been described in connection with some embodiments thereof, it should be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention as understood by those skilled in the art. something to do. It is also contemplated that such variations and modifications are within the scope of the claims appended hereto.

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

Claims (18)

As a control channel transmission method of a base station,
Allocating a transmission unit resource (PRB) region for a relay control channel (R-PDCCH) on a downlink subframe in RB units on a frequency axis; And
A control channel transmission method comprising transmitting a transmission mode and antenna port information. The method of claim 1,
And allocating a relay data channel (R-PDSCH) to an area of a transmission unit resource (PRB) to which a relay control channel is not allocated. The method of claim 2,
The base station uses a transmission mode 8 for transmitting two layers using two antenna ports. The method of claim 3,
The relay control channel is transmitted through antenna ports 7 and 8. 5. The method of claim 4,
In the first layer, the R-PDCCH and the R-PDSCH of the first slot are transmitted through the antenna port 7, and in the second layer, the R-PDCCH and the R-PDSCH are transmitted through the antenna port 7 and the first The R-PDSCH of the second slot in the layer is transmitted through antenna port 7 and the R-PDSCH of the second slot in the second layer is transmitted through antenna port 8. As a control channel transmission method,
a) allocating a transmission unit resource (PRB) region for a relay control channel (R-PDCCH) on a downlink subframe in units of OFDM symbols on a time axis; And
b) transmitting a transmission mode and antenna port information. The method according to claim 6,
Step a), the control channel transmission method for allocating different transmission unit resource region for the R-PDCCH of each relay for each layer (Layer). The method of claim 7, wherein
The base station uses a transmission mode 8 for transmitting two layers using two antenna ports. 9. The method of claim 8,
The relay control channel is transmitted through antenna ports 7 and 8. 10. The method of claim 9,
The R-PDCCH of the first and second slots for the first relay in the first layer is transmitted through antenna port 7 and the R-PDCCH of the first and second slots for the second relay in the second layer is the antenna port. Transmitted over 8; 11. The method according to any one of claims 1 to 10,
The transmission mode and antenna port information is transmitted using an RRC message. A mobile communication system,
A transmission unit resource (PRB) region for a relay control channel (R-PDCCH) on a downlink subframe is first allocated in a resource block (RB) unit on a frequency axis or secondly in an OFDM symbol unit on a time axis, and then transmitted. A mobile communication system comprising a base station transmitting mode and antenna port information. The method of claim 12,
And a relay for blind decoding the R-PDCCH using the transmission mode and the antenna port information to demodulate data according to R-PDSCH scheduling information. The method of claim 12,
The base station allocates a relay data channel (R-PDSCH) to an area of a transmission unit resource (PRB) to which a relay control channel is not allocated when the first allocation is performed, or R of each relay for each layer when the second allocation is performed. A mobile communication system for allocating different transmission unit resource regions for PDCCH. . The method of claim 12,
The base station uses a transmission mode 8 that transmits two layers using two antenna ports,
The relay control channel is transmitted through antenna ports 7 and 8. 16. The method of claim 15,
In the first layer, the R-PDCCH and the R-PDSCH of the first slot are transmitted through the antenna port 7, and in the second layer, the R-PDCCH and the R-PDSCH are transmitted through the antenna port 7 and the first The R-PDSCH of the second slot in the layer is transmitted through antenna port 7, and the R-PDSCH of the second slot in the second layer is transmitted through antenna port 8. 16. The method of claim 15,
The R-PDCCH of the first and second slots for the first relay in the first layer is transmitted through antenna port 7 and the R-PDCCH of the first and second slots for the second relay in the second layer is the antenna port. 8, which is transmitted via 8. The method according to any one of claims 11 to 17,
The transmission mode and antenna port information are transmitted using an RRC message.
The base station multiplexes and transmits the R-PDCCH and the R-PDSCH.

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