KR20100102513A - Method and apparatus for allocating backhaul transmission resource of in wireless communication systems based on relay - Google Patents

Abstract

PURPOSE: A method for assigning backhaul transmitting resource in a wireless communication system and a device for the same are provided to remove the superposition of transceiving timing of relay node according to a RF transceiving switching time delay, thereby increasing availability of wireless backhaul resource. CONSTITUTION: A symbol generators(1401~1403) generates a SRS(Sounding Reference Signal), a RS(Reference Signal), and PUSCH(Physical Uplink Shared Channel) symbols. A FFT(Fast Fourier Transform) unit(1404) converts the PUSCH symbols into frequency band width signal. A subcarrier symbol mapper(1405) maps the SRS symbol, the RS symbol, and the converted PUSCH symbols in allocated resource area. A PUSCH symbol generation and mapping controller(1400) considers a symbol for a blank, and controls the symbol generator and the subcarrier symbol mapper.

Description

Method for allocating backhaul transmission resources in relay-based wireless communication system and apparatus therefor {Method and Apparatus for Allocating Backhaul Transmission Resource of in wireless communication systems based on relay}

The present invention relates to a wireless relay of a wireless communication system, and more particularly, to a method and apparatus for designing a structure of an uplink and a downlink backhaul subframe for a Layer-3 (hereinafter referred to as L3) relay including a base station function.

In recent mobile communication systems, orthogonal frequency division multiple access (OFDM), or a similar method, is useful for high-speed data transmission in a wireless channel. SC-FDMA) is being actively studied. Currently, OFDM and SC-FDMA technologies are applied to downlink and uplink of the Evolved UMTS Terrestrial Radio Access (EUTRA) standard based on 3rd Generation Partnership Project (3GPP) Universal Mobile Telecommunication Services (UMTS). SC-FDMA, like OFDM, guarantees orthogonality among multiple access users and is based on single carrier transmission, and has the advantage of low peak power to average power ratio (PAPR) of a transmission signal. Therefore, when SC-FDMA is applied to a mobile communication system, cell coverage is improved due to lower PAPR than OFDM technology.

Since LTE-Advanced (hereinafter, LTE-A) system transmits data at a higher speed than LTE system, a new technique is required to compensate for signal distortion. This is because signal distortion due to channel path loss is a fundamental limitation in transmitting data at high speed in limited resources. In order to overcome this problem, the wireless relay technology is located between the first transmitting end and the last receiving end, and the wireless relay node compensates the path loss of the signal transmitted from the first transmitting end and transmits it to the final receiving end. Therefore, the wireless relay technology improves the path loss generated between the first transmitting end and the last receiving end, thereby improving performance of the cell edge terminal and extending system coverage.

On the other hand, when the radio relay node simultaneously receives and transmits a signal, the transmitted signal acts as a large interference of the received signal. Therefore, it is necessary to distinguish between the reception link and the transmission link of the radio relay node. The transmission and reception links of the wireless relay node can be classified as shown in Table 1 below.

TABLE 1

Time division Dividing the transmit and receive links into different time resources in the same frequency band Frequency division Divide outgoing and receiving links from the same time resource to other frequency resources

Since the frequency division scheme of Table 1 requires wide spacing between two frequency bands to avoid interference between frequency bands, time division link division is generally used for efficient allocation of frequency resources.

In addition, the wireless relay system can be classified into four types according to the relay node function as shown in Table 2 below.

TABLE 2

Layer-0 (L0) Relay Amplify and forward all received signals Layer-1 (L1) Relay Amplify and Receive Received Signals Layer-2 (L2) Relay Demodulate, decode, encode, modulate, and forward incoming signals Layer-3 (L3) Relay Perform base station functions including relay functions

According to the L3 relay system of Table 2, it is possible to distinguish a relay node cell and a base station cell, improve frequency resource utilization, and facilitate the introduction of a wireless relay in a cellular system.

The singularity of the L3 relay system is the wireless backhaul link between the base station and the relay node. The wireless backhaul link means that the relay node receives downlink data of terminals belonging to the base station from the base station or the relay node transmits uplink data of the terminals to the base station, and the relay node refers to the wireless backhaul link and the terminal belonging to the base station. The linkage with each other is divided by time division method.

The relay node must perform RF transmission and reception switching before and after the backhaul subframe, and this operation causes an RF transmission and reception switching time delay in the relay node. Accordingly, the uplink and downlink backhaul subframe structures in the L3 relay system should be designed in consideration of the RF transmission / reception switching time delay and compatibility with the general uplink and downlink subframe structures.

A method and apparatus for allocating backhaul transmission resources in a relay-based wireless communication system of the present invention are provided to provide an uplink backhaul subframe structure and a downlink backhaul subframe structure in an L3 relay system. In particular, the method and apparatus for allocating backhaul transmission resources in the relay-based wireless communication system of the present invention reduces the RF transmission / reception switching time delay inevitably generated by using the L3 relay and the conventional uplink and downlink subframe structures. An object of the present invention is to provide an uplink and downlink backhaul subframe structure in which compatibility is guaranteed.

In the relay-based wireless communication system of the present invention for solving the above problems, the method for allocating uplink backhaul transmission resources of a relay node acquires information for obtaining scheduling information for uplink backhaul transmission from a base station through a downlink backhaul control channel Step, Confirming whether the uplink backhaul subframe is set to transmit a Sounding Reference Signal (SRS) through the scheduling information, If it is confirmed that the subframe does not include the SRS, Rate mapping and mapping data except for a blank symbol and a reference signal (RS) symbol in an allocated resource region, and the blank and the blank in the allocated resource region. Multiplexing the multiplexing RS and the SRS; And that is characterized.

In addition, in the relay-based wireless communication system of the present invention for solving the above problems, the method for allocating uplink backhaul transmission resources of a base station schedules resources for downlink backhaul of a relay node and downlink resources of terminals belonging to a base station cell. In the scheduling step, the control symbols of the scheduled relay node and the terminals are mapped to a downlink control channel (PDCCH) region, and the data symbols of the scheduled terminal are downlink shared channel (Physical Downlink Shared Channel); A first mapping step of mapping to a PDSCH region, one symbol for a switching time delay at the end of a subframe, and N symbols used for the PSCHCH transmission of the relay node except for the N symbols used for the PDCCH transmission of the relay node. Rate match data, and A second mapping step of mapping matched data symbols to a PDSCH region except for N + 1 symbols positioned at the end of the subframe, and a multiplexing step of multiplexing PDCCH, PDSCH, and RS of a scheduled relay node and a terminal; It is characterized by.

In addition, the apparatus for allocating an uplink backhaul transmission resource of a relay node in the relay-based wireless communication system of the present invention for solving the above problems includes a sounding reference signal (SRS), a reference signal (Reference Signal, RS) and A plurality of symbol generators for generating Physical Uplink Shared Channel (PUSCH) symbols, A Fast Fourier Transform (FFT) device for receiving the PUSCH symbols into a frequency band signal, The SRS symbol, The A subcarrier symbol mapper that receives an RS symbol and the Fourier transformed PUSCH symbols and maps them to an allocated resource region, and controls to perform rate matching in consideration of a blank symbol in the symbol generator that generates the PUSCH symbol, and the subcarrier symbol In the mapper, the input symbols are mapped to an area excluding a blank symbol. And an uplink physical channel symbol generation and mapping controller that controls the control to be possible.

In addition, the apparatus for allocating a downlink backhaul transmission resource of a base station in a relay-based wireless communication system of the present invention for solving the above problems includes a reference signal (RS) subcarrier symbol and a downlink control channel (PDCCH). A plurality of symbol generators for generating a subcarrier symbol and a physical downlink shared channel (PDSCH) subcarrier symbol, the RS subcarrier symbol, the PDCCH subcarrier symbol, and the PDSCH subcarrier symbol and receive a subcarrier for mapping to a corresponding subframe A symbol mapper and a symbol generator for generating the PDSCH subcarrier symbol are controlled to perform rate matching of data in consideration of a blank symbol, and the input symbols in the subcarrier symbol mapper are considered to be the symbol for the blank. To be mapped to a frame It characterized in that it comprises a downlink physical channel symbol generation and mapping controller for controlling.

According to the present invention, the overlapping of the transmission / reception timing of the relay node due to the RF transmission / reception switching time delay is eliminated, and the compatibility with the conventional uplink and downlink subframe structures is provided to increase the utilization of the wireless backhaul resource and at the same time, The impact on the system can be minimized.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this case, it should be noted that like elements are denoted by like reference numerals as much as possible. Further, the detailed description of well-known functions and constructions that may obscure the gist of the present invention will be omitted.

In addition, in describing the embodiments of the present invention specifically, SC-FDMA and OFDM-based wireless communication system, in particular the 3GPP EUTRA standard will be the main target, but the main subject of the present invention has a similar technical background and channel form Other communication systems can be applied with minor modifications without departing from the scope of the present invention, which will be determined by those of ordinary skill in the art.

1 is a block diagram illustrating a structure and a slot structure of an SC-FDMA transmitter. In particular, the transmitter illustrated in FIG. 1 is characterized by using a Fast Fourier Transform (FFT) device 103 and an Inverse Fast Fourier Transform (IFFT) device 105.

Looking at the difference between OFDM and SC-FDMA in terms of the transmitter structure with reference to Figure 1, there is an IFFT device 105 used for multi-carrier transmission in the OFDM transmitter, while in the SC-FDMA transmitter, the FFT device 103 is IFFT It is additionally present in front of the device 105. M modulation symbols 100 are gathered to form a block, and the block is input to an FFT apparatus 103 having a size M. The block is hereinafter referred to as Long Block (LB), and seven LBs constitute one 0.5 ms slot 102. The LB after the FFT processing becomes an SC-FDMA symbol, and seven SC-FDMA symbols constitute one 0.5 ms slot.

The signal output from the FFT apparatus 103 is applied to the inputs of the IFFT apparatus 105 having a continuous index (104), undergoes a reverse fast Fourier transform, and is then converted into an analog signal (106) and transmitted. The input / output size N of the IFFT device 105 has a larger value than the input / output size M of the FFT 103. The reason why the SC-FDMA transmission signal has a lower peak-to-average power ratio (PAPR) than that of the OFDM signal is that a signal processed through the FFT device 103 and the IFFT device 105 has a single carrier characteristic. Because it has.

FIG. 2 is a diagram illustrating SC-FDMA based uplink and OFDM based downlink frame structures of EUTRA, which is the next-generation mobile communication technology standard of 3GPP.

Referring to FIG. 2, there are a total of 50 resource blocks (RBs) 202 in a system bandwidth 201 of 10 MHz. One RB is composed of 12 subcarriers 203, and may have 14 SC-FDMA symbol intervals 204 in the uplink and 14 OFDM symbol intervals 206 in the downlink. have. Here, the SC-FDMA symbol interval and the OFDM symbol interval are the same, and each RB is a scheduling unit of basic data transmission. Fourteen SC-FDMA symbols or OFDM symbols are collected to form one 1 ms subframe 205.

FIG. 3 is a diagram illustrating a resource allocation structure for transmitting an SC-FDMA based uplink control channel and a data channel in a long term evolution (LTE) system.

Referring to FIG. 3, a physical uplink control channel (PUCCH) 306 is transmitted on RBs located at both ends of a system band, and a sounding reference signal (SRS) 309 is provided. Is transmitted over the 10 MHz full-band 303 of the last SC-FDMA symbol 305, and each SRS of users in the cell is guaranteed to be orthogonal. The physical uplink shared channel (PUSCH) 307 is transmitted in a region excluding a PUCCH and SRS region of a system band, and a reference signal (RS, 308) is transmitted in each slot 302 in the PUSCH region. Is transmitted in the middle SC-FDMA symbol.

The PUCCH includes ACK (Acknowledge) / NACK (Negative ACK) information for a hybrid automatic repeat reQuest (HARQ) operation, and channel quality indication (CQI), which is channel state information for scheduling downlink data. In addition, SRS is a signal for acquiring uplink channel state information for each user and adjusting uplink transmission timing for the entire system, and RS is a signal for obtaining channel state information used for demodulation and decoding of a PUSCH.

4 is a diagram illustrating a resource allocation structure for OFDM-based downlink control channel and data channel transmission in an LTE system.

Referring to FIG. 4, one subframe includes 14 OFDM symbols 400 to 413, and an area allocated for a downlink control channel (PDCCH) is located at the front of the subframe. It is allocated, and up to three OFDM symbols 400 to 402 can be allocated from at least one OFDM symbol 400. In particular, in FIG. 4, the two previous OFDM symbols 400 and 401 are allocated. In addition, the region allocated for the downlink shared channel (PDSCH) is the remaining 12 OFDM symbols (402 to 413).

In the first OFDM symbol of the PDCCH region, a Physical Control Format Indicator Channel (PCFICH) indicating the length of the PDCCH region and a Physical Hybrid ARQ Indicator Channel (PHICH) indicating ACK / NACK information are transmitted. In addition, the PDCCH includes user data allocation information and data MCS (Modulation and Coding Scheme) information. The reason why the area for the PDCCH is located at the beginning of the subframe is that the UE first checks the PDCCH and then takes a micro sleep mode when there is no data allocation information corresponding to the PDCCH. To reduce the cost. RS is distributedly located in the PDCCH region and the PDSCH region for demodulation and decoding of each channel.

Hereinafter, when the L3 relay system is introduced, an uplink and downlink backhaul subframe structure for wireless backhaul communication will be described. In particular, it maintains compatibility with the conventional SC-FDMA-based uplink subframe structure and the OFDM-based downlink subframe structure, and the uplink can reduce the RF transmission and reception switching time delay inevitably generated when using the L3 relay system. The link backhaul subframe structure and the downlink backhaul subframe structure will be described.

<First Embodiment>

FIG. 5 is a diagram illustrating an uplink subframe structure of an L3 relay system for uplink backhaul according to a first embodiment of the present invention. In particular, the first embodiment considers a case in which SRS transmission is allowed in an uplink backhaul subframe. The SRS is used to adjust the transmission timing of the relay node, and the channel state information for the frequency domain of the wireless backhaul link obtained by the base station through the SRS is used for scheduling the wireless backhaul resource.

Referring to FIG. 5, since the relay node cannot receive the uplink backhaul subframe 501 transmitted by the relay node RN to the base station eNB, the terminal belongs to the relay node cell as shown by reference numeral 504. Do not allocate uplink resources to the (UE). In a section other than the uplink backhaul subframe, it is a section of uplink subframes 505 and 506 of terminals belonging to the relay node cell, and the relay node performs a reception operation of signals transmitted from the terminals during this section.

In addition, the synchronization of the uplink backhaul subframe of the relay node is consistent with the synchronization of the uplink subframes of the terminals belonging to the base station cell. Therefore, in the uplink backhaul subframe, the SRS 503 should be located in the last SC-FDMA symbol, which is the same position as the general surf frame structure, in order to maintain orthogonality with the SRS transmission of the UEs belonging to the base station cell.

Meanwhile, in the uplink backhaul subframe, the PUSCH 509 and RS 507 structures follow the conventional PUSCH 510 and RS 508 structures to enable uplink resource allocation of terminals belonging to a base station cell. Therefore, uplink resources of terminals belonging to a relay node cell may be transmitted by frequency division multiplexing (FDM) in the PUSCH 510 of the uplink access subframes 505 and 506, and the uplink backhaul subframe An uplink backhaul resource of a relay node and uplink resources of terminals belonging to a base station cell may be frequency-division multiplexed and transmitted in the PUSCH 509 area of 501.

Meanwhile, switching from RF reception to RF transmission is required immediately before transmission of the uplink backhaul subframe, and switching from RF transmission to RF reception is required immediately after transmission of the uplink backhaul subframe. The RF transmit / receive switching time delay caused by this should be considered in the uplink backhaul subframe 501.

In case of the first embodiment, the RF transmission / reception switching time delay is considered while maintaining the proposed subframe structure. That is, the relay node abandons the transmission of the first SC-FDMA symbol 502, and delays the transmission timing of the uplink access subframe 506, which is the timing at which the terminal transmits to the relay node, by the RF transmission / reception switching time delay. Consider the switching time delay in the first SC-FDMA symbol period 502 of the uplink backhaul subframe 501.

6 is a flowchart illustrating a transmission procedure of a relay node for uplink backhaul of an L3 relay system according to a first embodiment of the present invention.

Referring to FIG. 6, the relay node obtains scheduling information for uplink backhaul transmission from the base station in step 600. This scheduling information can be obtained through the control channel of the downlink backhaul transmitted from the base station to the relay node. In step 601, the relay node checks whether the scheduled uplink backhaul subframe is set to transmit the SRS. This confirmation is required because the PUSCH region of the subframe including the SRS and the subframe not including the SRS are different. That is, in the case of the subframe including the SRS, the last SC-FDMA symbol is excluded from the PUSCH region, and in the case of the subframe not including the SRS, the last SC-FDMA symbol is included in the PUSCH region.

If it is determined in step 601 that the scheduled uplink backhaul subframe transmits SRS, then in step 602 the relay node has a SC-FDMA symbol for blank, an SC-FDMA symbol for RS and SRS for the allocated RB resource. Rate matching of data is performed in consideration of resource regions excluding SC-FDMA symbols. In addition, in step 603, the relay node maps the rate-matched data symbols to resource regions except for the first SC-FDMA symbol for blank, the fourth and eleventh SC-FDMA symbol for RS, and the last SC-FDMA symbol for SRS. Subsequently, in step 604, a blank is allocated to the first SC-FDMA symbol, an RS is multiplexed to the fourth and eleventh SC-FDAM symbols, and an SRS is multiplexed to the last SC-FDMA symbol and transmitted to the base station.

If it is confirmed in step 601 that the scheduled uplink backhaul subframe does not transmit the SRS, in step 605 the relay node removes the resource region excluding the SC-FDMA symbol for the blank and the SC-FDMA symbol for the RS from the allocated RB resources. In consideration of the rate matching of the data. In step 606, the relay node maps the rate-matched data symbols to resource regions except for the first SC-FDMA symbol for blank and the fourth and eleventh SC-FDMA symbol for RS. Subsequently, in step 607, blanks are multiplexed on the first SC-FDMA symbol, RSs are multiplexed on the fourth and eleventh SC-FDAM symbols, and transmitted to the base station.

7 is a flowchart illustrating a reception procedure of a base station for uplink backhaul of a wireless communication L3 relay system according to a first embodiment of the present invention.

Referring to FIG. 7, the base station determines whether the subframe received in step 701 is set to transmit SRS. If it is determined in step 701 that the received subframe is set to transmit the SRS, in step 702 the base station demultiplexes the SRS, RS and PUSCH in the received subframe. In operation 703, data symbols of the PUSCH region except for the first SC-FDMA symbol are de-mapping in the RB allocated as the uplink backhaul. In step 704 the base station decodes the demapped data symbols to obtain uplink backhaul data.

On the other hand, if it is determined in step 701 that the subframe received does not transmit the SRS, the base station demultiplexes the RS and the PUSCH in the subframe received in step 705. In step 706, de-mapping the data symbols of the PUSCH region except for the first SC-FDMA symbol from the RB resource allocated as the uplink backhaul, and in step 707, the base station decodes the de-mapped data symbols to uplink Acquire backhaul data.

In the first embodiment, one blank SC-FDMA symbol is considered, but one or more blank SC-FDMA symbols may be considered according to RF transmission / reception switching time delay and timing adjustment related variable values.

&Lt; Embodiment 2 >

8 illustrates an uplink subframe structure of an L3 relay system for uplink backhaul according to a second embodiment of the present invention. In particular, the second embodiment is limited to the case in which the uplink backhaul subframe does not transmit the SRS.

Referring to FIG. 8, since the relay node cannot receive the uplink backhaul subframe 801 transmitted by the relay node RN to the base station eNB as described above, the relay node cannot receive the relay as shown by reference numeral 803. Uplink resources are not allocated to UEs belonging to the node cell. Since the relay node performs a reception operation in a section other than the uplink backhaul subframe, the relay node performs a reception operation of signals transmitted from the terminals in the uplink access subframes 804 and 805 of the terminals belonging to the relay node cell. To perform.

Also, since the synchronization of the uplink backhaul subframe of the relay node coincides with the synchronization of the uplink subframe of the terminals belonging to the base station cell. In the uplink backhaul subframe, the PUSCH 808 and RS 806 structures use the conventional PUSCH 809 and RS 807 structures to enable uplink resource allocation of terminals belonging to a base station cell. Accordingly, in the PUSCH 809 regions of the uplink access subframes 804 and 805, uplink resources of the terminals belonging to the relay node cell may be transmitted by frequency division multiplexing, and the PUSCH of the uplink backhaul subframe 801 may be transmitted. In the region 808, uplink backhaul resources of the relay node and uplink resources of terminals belonging to the base station cell may be transmitted by frequency division multiplexing.

On the other hand, switching from RF reception to RF transmission is required immediately before transmission of the uplink backhaul subframe, switching from RF transmission to RF reception is required immediately after transmission of the uplink backhaul subframe, and the RF transmission / reception switching time delay is increased. It should be considered in the link backhaul subframe 801. However, in the second embodiment, unlike the first embodiment, transmission of the last SC-FDMA symbol period 802 is abandoned. This is because the synchronization of the uplink backhaul subframe of the relay node coincides with the synchronization of the uplink subframe of the UEs belonging to the base station cell, and the uplink backhaul subframe does not transmit the SRS. This is to prevent collision of backhaul data.

As such, when abandoning the transmission of the last SC-FDMA symbol, the relay node advances the transmission timing of the uplink access link, which is a timing that the terminal transmits to the relay node, by an RF transmission / reception switching time delay, and thus the last SC of the uplink backhaul subframe 801. Consider the switching time delay in the FDMA symbol period 802.

The transmission procedure of the relay node according to the second embodiment corresponds to steps 605 to 607, which is a case of a subframe without SRS transmission in FIG. 6, and a reception procedure of a base station for a subframe without SRS transmission in FIG. 7. The case corresponds to steps 705 to 707. However, unlike the first embodiment, using the last SC-FDMA symbol for blanking is applied in steps 606, 607, and 706. In addition, although one blank SC-FDMA symbol is considered in the second embodiment, one or more blank SC-FDMA symbols may be considered according to RF transmission / reception switching time delay and timing adjustment related variable values.

Third Embodiment

9 illustrates a downlink subframe structure of an L3 relay system for downlink backhaul according to a third embodiment of the present invention.

Referring to FIG. 9, the relay node RN transmits the PDCCH 912 to UEs belonging to the relay node immediately before receiving the downlink backhaul subframe from the base station eNB. In the link backhaul subframe, the PDCCH 902 and the PDSCH 903 of the terminals belonging to the base station cell may be transmitted by frequency division multiplexing. This structure is to maintain compatibility with the conventional LTE system.

In the third embodiment, RF transmission / reception switching time delays occur just before reception 906 and immediately after reception 907 of the downlink backhaul subframe. In order to reflect this switching time delay in the backhaul subframe, the base station does not use the last OFDM symbol in the downlink backhaul transmission.

In addition, as shown in FIG. 9, since the backhaul reception interval of the relay node is the PDSCH region interval 913 immediately after the relay node transmits the PDCCH 912, the last OFDM symbol interval that should be set to a blank at the base station is an RF transmission / reception switching time delay. In addition, the PDCCH 912 region section transmitted by the relay node should be considered. That is, a resource that is not used by the base station when allocating resources to a downlink backhaul subframe includes N + 1 OFDM plus one OFDM symbol for switching time delay and N OFDM symbols used for transmission of the PDCCH 912 of the relay node. Symbol. This applies to the last OFDM symbols 905 of the backhaul resource in the downlink backhaul subframe. Here, the length of the PDCCH 912 region transmitted by the relay node may be fixed or may be changed through an upper signal. The relay node may adjust timing with a terminal belonging to the relay node cell based on the reception timing of the downlink backhaul subframe as shown in FIG. 9.

10 is a flowchart illustrating a transmission procedure of a base station for downlink backhaul of an L3 relay system according to a third embodiment of the present invention.

Referring to FIG. 10, the base station schedules resources for downlink backhaul of the relay node and downlink resources of terminals belonging to the base station cell in step 1000. In addition, control symbols of the relay node and the UE scheduled in step 1001 are mapped to the PDCCH region, and data symbols of the UE scheduled in the step 1002 are mapped to the PDSCH region.

Subsequently, in step 1003, rate matching is performed in consideration of a PDSCH region excluding N + 1 OFDM symbols for data of the scheduled relay node. In step 1004, the rate matched data symbols are mapped to the PDSCH region except for the last N + 1 OFDM symbols. In step 1005, the base station multiplexes the PDCCH, PDSCH, and RS of the relay node and the terminal and transmits the multiplexed signals.

11 is a flowchart illustrating a receiving procedure of a relay node for downlink backhaul of an L3 relay system according to a third embodiment of the present invention.

Referring to FIG. 11, the PDCCH, PDSCH, and RS are demultiplexed in a downlink backhaul subframe received from the base station in step 1100. In step 1101, the relay node decodes the PDCCH corresponding to itself to obtain scheduling information (ie, resource allocation information and modulation and coding levels) of the downlink backhaul. In addition, the data symbols are de-mapped in a region excluding the last N + 1 OFDM symbols among the PDSCH regions allocated in step 1102, and the relay node decodes the data symbols demapped in step 1103 to obtain downlink backhaul data.

In the third embodiment, one blank OFDM symbol is considered in order to consider an RF transmission / reception switching time delay, but one or more blank OFDM symbols may be considered according to timing adjustment related variable values.

<< fourth embodiment >>

12 illustrates a downlink subframe structure of an L3 relay system for downlink backhaul according to a fourth embodiment of the present invention. Unlike the third embodiment, the fourth embodiment considers a structure in which a PDCCH and a PDSCH 1204 of a downlink backhaul are transmitted together in a conventional PDSCH region in a downlink backhaul subframe. That is, in the downlink backhaul subframe, only the PDCCHs of the UEs belonging to the base station are transmitted to the conventional PDCCH region 1202, and the downlink backhaul related PDCCH is divided into time division multiplexing and frequency division multiplexing or PDSCH in the PDSCH region. Joint coding may be jointly coded and transmitted to the PDSCH region. For this structure, the base station must inform the relay node of the downlink backhaul resource region in advance through an upper signal.

Referring to FIG. 12, the relay node transmits the PDCCH 1212 to terminals belonging to the relay node immediately before receiving the downlink backhaul subframe from the base station, and the base station belongs to the base station cell in the downlink backhaul subframe. The PDCCH 1202 and the PDSCH 1203 of the UEs may be transmitted by being divided into frequency division multiplexing. This structure is to maintain compatibility with the conventional LTE system.

In the fourth embodiment, an RF transmission / reception switching time delay occurs immediately before the reception of the downlink backhaul resource 1206 and immediately after the reception 1207. In order to consider this in the backhaul subframe, the base station transmits the last OFDM symbol in the downlink backhaul transmission. Do not use In the fourth embodiment, unlike the third embodiment, since the relay node does not need to receive the PDCCH 1202 from the base station, the reception start timing of the relay node becomes the PDSCH start timing of the downlink backhaul subframe. Therefore, since it is not necessary to consider the blanks of the N OFDM symbols generated in the third embodiment, FIG. 12 considers only the RF transmission / reception switching time delay of the last OFDM symbol to be left blank in the base station. This empty resource is applied to the last OFDM symbols 1205 of the backhaul RB resource in the downlink backhaul subframe.

The relay node may adjust the transmission timing with the terminal belonging to the relay node cell based on the reception timing of the downlink backhaul subframe from the base station as shown in FIG. 12.

In the transmission procedure of the base station according to the fourth embodiment, the PDCCH and the PDSCH of the downlink backhaul are transmitted together in the conventional PDSCH region in step 1001 of FIG. 10, and only the last OFDM symbol is used for the blanks in steps 1003 and 1004. If applicable, it can be implemented.

In addition, in the reception procedure of the relay node according to the fourth embodiment, the PDCCH of the downlink backhaul is obtained from a resource pre-allocated for downlink backhaul, that is, a conventional PDSCH region, in step 1100 of FIG. 11, and only the last OFDM symbol in step 1102. It can be implemented if applied to use for blank.

In the fourth embodiment, one blank OFDM symbol is considered as an RF transmission / reception switching time delay, but one or more blank OFDM symbols may be considered according to timing adjustment related variable values.

<Fifth Embodiment>

FIG. 13 is a diagram illustrating an uplink subframe structure of an L3 relay system for uplink backhaul according to a fifth embodiment of the present invention. In particular, the fifth embodiment considers a case in which SRS transmission is allowed in an uplink backhaul subframe similarly to the first embodiment. The SRS is used to adjust the transmission timing of the relay node, and the channel state information for the frequency domain of the wireless backhaul link obtained by the base station through the SRS is used for scheduling the wireless backhaul resource.

Referring to FIGS. 5 and 13, the first embodiment defers an uplink backhaul subframe 501 by delaying a transmission timing of an uplink access link, which is a timing that a terminal transmits to a relay node, by an RF transmission / reception switching time delay. Consider the switching time delay in the first SC-FDMA symbol period 502 of. On the other hand, the fifth embodiment transmits the first and second SC-FDMA symbols 1302 in order to consider not only the RF transmission / reception switching time delay but also the change in the timing of uplink backhaul subframe transmission due to the change in the reception timing of the downlink backhaul subframe. To give up.

At this time, if the position of the RS symbol can be moved in the uplink backhaul subframe structure, the RS symbol located in the fourth SC-FDMA symbol 507 is reduced to reduce the channel estimation error in the PUSCH 1309 located from the third. The position may be moved to the first SC-FDMA symbol 1307.

In the uplink backhaul subframe 1301, which the relay node RN transmits to the base station eNB, since the relay node cannot receive a signal, the uplink resource 1304 is provided to the UEs belonging to the relay node cell. Do not assign. In the section other than the uplink backhaul subframe, the relay node performs the reception operation during the section in the uplink subframes 1305 and 1306 of the terminals belonging to the relay node cell.

In addition, the synchronization of the uplink backhaul subframe of the relay node is consistent with the synchronization of the uplink subframes of the terminals belonging to the base station cell. Therefore, in the uplink backhaul subframe, the SRS 1303 must be located in the last SC-FDMA symbol, which is the same position as the conventional one, in order to maintain orthogonality with the SRS transmission of the UEs belonging to the base station cell.

In the PUSCH 1310 regions of the uplink access subframes 1305 and 1306, uplink resources of terminals belonging to a relay node cell may be transmitted by frequency division multiplexing, and the PUSCH 1309 of the uplink backhaul subframe 1301 may be transmitted. In the region, an uplink backhaul resource of a relay node and uplink resources of terminals belonging to a base station cell may be transmitted by frequency division multiplexing.

Meanwhile, switching from RF reception to RF transmission is required immediately before the uplink backhaul subframe, and switching from RF transmission to RF reception immediately after the uplink backhaul subframe is required. Due to this, RF transmission / reception switching time delay occurring should be considered in the uplink backhaul subframe 1301. In addition, the transmission timing of the uplink backhaul subframe may vary according to the reception timing of the downlink backhaul subframe. Therefore, the timing change must also be considered additionally.

In the fifth embodiment, while maintaining the proposed subframe structure, the transmission timing change of the uplink backhaul subframe according to the RF transmission / reception switching time delay and the reception timing change of the downlink backhaul subframe is considered. That is, the relay node abandons the transmission of the first and second SC-FDMA symbols 1302 and postpones the transmission timing of the uplink access link, which is a timing at which the terminal transmits to the relay node, behind one SC-FDMA symbol. Consider changes in the transmission timing of the uplink backhaul subframe according to the switching time delay and the reception timing of the downlink backhaul subframe in the first and second SC-FDMA symbol periods 1302 of the uplink backhaul subframe 1301. .

14 is a block diagram of a transmitter for uplink backhaul of a relay node according to the present invention.

Referring to FIG. 14, the SRS symbol generator 1401, the RS symbol generator 1402, and the PUSCH symbol generator 1403 of the relay node transmitter generate SRS, RS, and PUSCH symbols, respectively. The generated SRS symbol and the RS symbol are directly input to the subcarrier symbol mapper 1405 of 1405, and the PUSCH symbol is input to the subcarrier symbol mapper 1405 through the FFT device 1404. The output of the subcarrier symbol mapper 1405 is mapped to the input of the IFFT device 1406. In this case, the uplink physical channel symbol generation and mapping controller 1300 controls the PUSCH symbol generator 1403 to perform rate matching in consideration of the blank SC-FDMA symbol, and the subcarrier symbol mapper 1405 performs the blank SC-. Control so that the PUSCH symbol generated in the region excluding the FDMA symbol can be accurately mapped. The SRS symbol generator 1401 may not be used depending on the structure of the uplink backhaul subframe.

15 is a block diagram of a receiving apparatus for uplink backhaul of a base station according to the present invention.

Referring to FIG. 15, the FFT apparatus 1500 performs Fourier transform of a received uplink SC-FDMA signal to output respective subcarrier received symbols. The received symbols are divided into PUSCH, RS, and SRS symbols by the subcarrier symbol demapper 1501. The RS symbol is input to the RS symbol-based channel information generator 1505 to inform the channel compensator 1507 of the PUSCH symbol related channel state information to perform channel compensation of the PUSCH symbol received from the subcarrier symbol demapper.

The channel compensated PUSCH symbol is converted into a data symbol that can be decoded and decoded through the IFFT device 1503 and applied to the PUSCH symbol decoder 1504. The SRS symbol-based channel information generator 1506 receives SRS symbols from the subcarrier symbol demapper 1501 and generates channel information. This channel information is used when the base station schedules uplink backhaul resources.

The uplink physical channel symbol decoding and demapping controller 1502 controls to demap the PUSCH in consideration of the blank SC-FDMA symbol when demapping the PUSCH, RS, and SRS in the subcarrier symbol demapper 1501. In addition, the uplink physical channel symbol decoding and demapping controller 1502 controls operations of the PUSCH symbol decoder 1504, the RS symbol-based channel information generator 1505, and the SRS symbol-based channel information generator 1506. The SRS symbol-based channel information generator 1506 may not be used depending on the structure of the uplink backhaul subframe.

16 is a block diagram of a transmitter for downlink backhaul of a base station according to the present invention.

Referring to FIG. 16, the RS subcarrier symbol generator 1601, the PDCCH subcarrier symbol generator 1602, and the PUSCH subcarrier symbol generator 1603 of the base station transmitter generate subcarrier symbols of RS, PDCCH, and PDSCH channels, respectively. The generated symbols are mapped to the appropriate IFFT device 1605 inputs according to the subcarriers until each symbol is mapped through the subcarrier symbol mapper 1604.

The downlink physical channel symbol generation and mapping controller 1600 allows the subcarrier symbol mapper 1604 to accurately map the symbols of the channels in the corresponding subframe. In addition, the downlink physical channel symbol generation and mapping controller 1600 controls the PDSCH subcarrier symbol generator 1603 to perform rate matching of data in consideration of blank OFDM symbols, and performs a blank OFDM on the subcarrier symbol mapper 1604. Controls the mapping by considering the symbol. In the structure in which the PDCCH transmitted to the relay node in the downlink backhaul subframe is transmitted in the PDSCH region, the downlink physical channel symbol generation and mapping controller 1600 controls the subcarrier symbol mapper 1604 to control the PDCCH and PDSCH in the PDSCH region. The PDSCH subcarrier symbol generator 1603 may be controlled to perform the joint coding of the PDCCH and the PDSCH, and then the joint coded symbol may be controlled to be mapped to the PDSCH region by controlling the PDSCH subcarrier symbol generator 1603. can do.

17 is a block diagram of a receiving apparatus for downlink backhaul of a relay node according to the present invention.

Referring to FIG. 17, the FFT apparatus 1700 performs Fourier transform on a received downlink OFDM signal to output respective subcarrier received symbols, and the received symbols are received by the PDSCH, PDCCH, and RS by the subcarrier symbol demapper 1701. Are separated by symbols.

The RS symbol is input to the RS subcarrier-based channel information generator 1703 to inform the PDSCH subcarrier symbol decoder 1705 and the PDCCH subcarrier symbol decoder 1704 of the PDSCH and PDCCH symbol related channel state information, respectively, so that each decoder decodes the subcarrier symbol D. The PDSCH and PDCCH received from the mapper 1701 are decoded.

The downlink physical channel symbol decoding and demapping controller 1702 controls the subcarrier symbol demapper 1701 to demap the PDSCH in consideration of blank OFDM symbols when demapping the PDSCH, PDCCH, and RS, and the PDSCH subcarrier symbol The decoder 1705, the PDCCH subcarrier symbol decoder 1704, and the channel information generator 1703 are controlled. In a structure in which the PDCCH transmitted to the relay node in the downlink backhaul subframe is mapped to the PDSCH region, the downlink physical channel symbol decoding and demapping controller 1702 controls the subcarrier symbol demapper 1701 to control the PDCCH in the PDSCH region. The PDSCH subcarrier symbol decoder may be de-mapped and the PDSCH region may be decoded by PDCCH and PDSCH. 1705 may be controlled to decode the joint coded symbol.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are merely presented specific examples to easily explain the technical contents of the present invention and help the understanding of the present invention, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

1 is a block diagram showing the structure and slot structure of an SC-FDMA transmitter;

FIG. 2 is a diagram illustrating SC-FDMA based uplink and OFDM based downlink frame structures of EUTRA, which is the next-generation mobile communication technology standard of 3GPP.

3 is a diagram illustrating a resource allocation structure for transmitting an SC-FDMA based uplink control channel and a data channel in a Long Term Evolution (LTE) system.

4 is a diagram illustrating a resource allocation structure for transmitting an OFDM-based downlink control channel and a data channel in an LTE system.

5 illustrates an uplink subframe structure of an L3 relay system for uplink backhaul according to a first embodiment of the present invention.

6 is a flowchart illustrating a transmission procedure of a relay node for uplink backhaul of an L3 relay system according to a first embodiment of the present invention.

7 is a flowchart illustrating a receiving procedure of a base station for uplink backhaul of a wireless communication L3 relay system according to a first embodiment of the present invention.

8 illustrates an uplink subframe structure of an L3 relay system for uplink backhaul according to a second embodiment of the present invention.

9 illustrates a downlink subframe structure of an L3 relay system for downlink backhaul according to a third embodiment of the present invention.

10 is a flowchart illustrating a transmission procedure of a base station for downlink backhaul of an L3 relay system according to a third embodiment of the present invention.

11 is a flowchart illustrating a receiving procedure of a relay node for downlink backhaul of an L3 relay system according to a third embodiment of the present invention.

12 illustrates a downlink subframe structure of an L3 relay system for downlink backhaul according to a fourth embodiment of the present invention.

13 illustrates an uplink subframe structure of an L3 relay system for uplink backhaul according to a fifth embodiment of the present invention.

14 is a block diagram of a transmitter for uplink backhaul of a relay node according to the present invention;

15 is a block diagram of a receiving apparatus for uplink backhaul of a base station according to the present invention;

16 is a block diagram of a transmitter for downlink backhaul of a base station according to the present invention;

17 is a block diagram of a receiving device for downlink backhaul of a relay node according to the present invention;

Claims (10)

An information obtaining step of obtaining scheduling information for uplink backhaul transmission from a base station through a downlink backhaul control channel; Confirming whether an uplink backhaul subframe is set to transmit a sounding reference signal (SRS) through the scheduling information; When it is confirmed that the subframe that does not include the SRS is scheduled, data is rate matched and mapped except for a blank symbol and a reference signal (RS) symbol in the allocated resource region. Data Mapping Steps: and And multiplexing the multiplexed blanks, the RS and the SRS in the allocated resource region. 10. The uplink backhaul transmission resource allocation method of a relay node in a relay based wireless communication system. The method of claim 1, wherein, in the checking step, when it is confirmed that the subframe including the SRS is scheduled, The data mapping step further excludes the symbol for SRS in the allocated resource region. The multiplexing step further multiplexes the SRSs. The uplink backhaul transmission resource allocation method of the relay node in the relay-based wireless communication system. The method of claim 1 or 2, wherein the multiplexing step In a relay-based wireless communication system, multiplexing a blank reflecting an RF transmission / reception switching delay to a first symbol among the allocated resource regions, multiplexing an RS to a fourth and eleventh symbols, and multiplexing an SRS to a last symbol A method of allocating uplink backhaul transmission resources of a relay node. The method of claim 1 or 2, wherein the multiplexing step Multiplexing the blank reflecting the RF transmission / reception switching delay in the first symbol of the allocated resource region, multiplexing the blank reflecting the change in reception timing of the downlink backhaul subframe in the second symbol, and multiplexing the SRS in the last symbol An uplink backhaul transmission resource allocation method of a relay node in a relay based wireless communication system. 5. The method of claim 4, wherein said multiplexing step Uplink backhaul transmission resource allocation method of a relay node in a relay-based wireless communication system, characterized in that the RS is multiplexed to the fifth and eleventh symbols of the allocated resource region. A scheduling step of scheduling resources for downlink backhaul of a relay node and downlink resources of terminals belonging to a base station cell; Map control symbols of the scheduled relay node and the UEs to a downlink control channel (PDCCH) region and map data symbols of the scheduled UE to a downlink data channel (PDSCH) region Mapping to a first mapping step; Rate matching data of the scheduled relay node corresponding to a PDSCH region except for one symbol for switching time delay and N symbols used for PDCCH transmission of a relay node located at the end of a subframe, and the rate matched data A second mapping step of mapping symbols to PDSCH regions except for N + 1 symbols positioned at the end of the subframe; And And multiplexing the multiplexed PDCCH, PDSCH, and RS of the scheduled relay node and the terminal. A plurality of symbol generators for generating a sounding reference signal (SRS), a reference signal (Reference Signal, RS) and uplink data channel (Physical Uplink Shared Channel, PUSCH) symbols; A Fast Fourier Transform (FFT) device for receiving the PUSCH symbols and converting them into frequency band signals; A subcarrier symbol mapper which receives the SRS symbol, the RS symbol, and the Fourier transformed PUSCH symbols and maps them to an allocated resource region; And The symbol generator generating the PUSCH symbol controls to perform rate matching in consideration of a blank symbol, and controls the subcarrier symbol mapper to map the input symbols to a region excluding a blank symbol. Symbol generation and mapping controller; Uplink backhaul transmission resource allocation apparatus of a relay node in a relay-based wireless communication system comprising a. The method of claim 7, wherein An apparatus for allocating uplink backhaul transmission resources of a relay node in a relay-based wireless communication system, further comprising an inverse fast Fourier transform (IFFT) device for converting an output signal of the subcarrier symbol mapper into a time band. . A plurality of symbol generators for generating a reference signal (RS) subcarrier symbol, a downlink control channel (PDCCH) subcarrier symbol, and a downlink data channel (PDSCH) subcarrier symbol; A subcarrier symbol mapper which receives the RS subcarrier symbol, the PDCCH subcarrier symbol, and the PDSCH subcarrier symbol and maps them to a corresponding subframe; And The symbol generator for generating the PDSCH subcarrier symbol is controlled to perform rate matching of data in consideration of a blank symbol, and the input symbols are mapped to the corresponding subframe in consideration of the blank symbol in the subcarrier symbol mapper. Downlink backhaul transmission resource allocation apparatus of the base station in the relay-based wireless communication system comprising a; 10. The method of claim 9, wherein the downlink physical channel symbol generation and mapping controller When the PDCCH subcarrier symbol is configured to be mapped to the PDSCH region of the corresponding subframe, the PDCCH subcarrier symbol is controlled to map the PDCCH subcarrier symbol and the PDSCH subcarrier symbol to the PDSCH region. Backhaul transmission resource allocation device.

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