KR20110030268A - Method and appartus for transmitting uplink control signal in relay station - Google Patents

Abstract

PURPOSE: An uplink transmitting method of a relay station and an apparatus thereof in order to reduce interference between control signals are provided to maintain the orthogonally of an uplink control signal which is transmitted from a terminal to a base station. CONSTITUTION: A processor(610) sets up a plurality of symbols assigning an uplink control signal to a sub frame of a UL repeater station zone. The processor transmits the uplink control signal through the resource unit. In case the necessary transition time is included in sub frame in the signal transception switching to the repeater station, the processor transmits the uplink control signal from the symbol except for a plurality of symbols consisting of resource unit.

Description

Method and apparatus for transmitting uplink control signal of relay station {METHOD AND APPARTUS FOR TRANSMITTING UPLINK CONTROL SIGNAL IN RELAY STATION}

The present invention relates to wireless communication, and more particularly, to a method and apparatus for transmitting an uplink control signal of a relay station in a wireless communication system including a relay station.

The Institute of Electrical and Electronics Engineers (IEEE) 802.16e standard is the sixth standard for the International Mobile Telecommunications (IMT-2000) in the ITU-Radiocommunication Sector (ITU-R) under the International Telecommunication Union (ITU) in 2007. It was adopted under the name OFDMA TDD '. ITU-R is preparing the IMT-Advanced system as the next generation 4G mobile communication standard after IMT-2000. The IEEE 802.16 Working Group (WG) decided to implement the 802.16m project with the goal of creating an amendment specification for the existing IEEE 802.16e as a standard for the IMT-Advanced system at the end of 2006. As can be seen from the above objectives, the 802.16m specification implies two aspects: past continuity of modification of the 802.16e specification and future continuity of specification for next generation IMT-Advanced system. Accordingly, the 802.16m standard requires all the advanced requirements for the IMT-Advanced system to be maintained while maintaining compatibility with the Mobile WiMAX system based on the 802.16e standard.

One of the systems considered in the next generation wireless communication system is an Orthogonal Frequency Division Multiplexing (OFDM) system that can attenuate inter-symbol interference (ISI) effects with low complexity. OFDM converts serially input data symbols into N parallel data symbols and transmits the data symbols on N subcarriers. The subcarriers maintain orthogonality in the frequency dimension. Each orthogonal channel experiences mutually independent frequency selective fading, and the interval between transmitted symbols is increased, thereby minimizing intersymbol interference. Orthogonal Frequency Division Multiple Access (OFDMA) refers to a multiple access method for realizing multiple access by independently providing each user with a portion of available subcarriers in a system using OFDM as a modulation method. OFDMA provides each user with a frequency resource called a subcarrier, and each frequency resource is provided to a plurality of users independently so that they do not overlap each other. Eventually, frequency resources are allocated mutually exclusively for each user.

In an OFDMA system, frequency diversity scheduling can be obtained through frequency selective scheduling, and subcarriers can be allocated in various forms according to permutation schemes for subcarriers. In addition, the spatial multiplexing technique using multiple antennas can increase the efficiency of the spatial domain. In order to support such various techniques, it is necessary to transmit a control signal between the terminal and the base station. The control signal includes a CQI (Channel quality indicator) for reporting the channel status to the base station, an ACK / NACK (Acknowledgement / Not-acknowledgement) signal in response to data transmission, a bandwidth request signal for requesting allocation of radio resources, and multiple antennas Precoding information, antenna information, and the like in the system. The control signal is transmitted through a control channel.

Recently, a wireless communication system including a relay station (RS) has been developed. The relay station serves to extend cell coverage and improve transmission performance. By the base station serves the terminal located at the coverage boundary of the base station through the relay station, it is possible to obtain the effect of extending the cell coverage. In addition, the relay station can increase the transmission capacity by improving the transmission reliability of the signal between the base station and the terminal. Even if the terminal is within the coverage of the base station, the relay station may be used when it is located in the shadow area.

In a wireless communication system including such a relay station, the relay station frame requires a new frame structure different from the conventional one. When the RS transmits a signal to the BS, the frequency band used may be the same as the frequency band for receiving the signal from the RS. Alternatively, the relay station may have the same frequency band used when receiving a signal from the base station and a frequency band transmitting the signal to the relay terminal. It is difficult for a relay station to simultaneously transmit and receive a signal in the same frequency band due to self interference. Thus, time is needed to switch the mode of operation between transmission and reception of the signal. In general, it is assumed that the relay station cannot transmit or receive a signal at the operation mode switching time. Some subframes within the RS frame may include symbols used as transition gaps in consideration of the operation mode switching time. In such a symbol, the RS cannot transmit an uplink control signal.

Therefore, when the conventional method of transmitting the uplink control signal between the base station and the terminal between the base station and the relay station may cause a problem due to the switching time. For example, there may be a multiplexing method of an uplink control signal transmitted by a relay station and an uplink control signal transmitted by a terminal or a problem of maintaining orthogonality of the multiplexed signal.

There is a need for a method of transmitting an uplink control signal to a base station by a relay station in a relay station frame including a switching time.

An object of the present invention is to provide a method and apparatus for transmitting an uplink control signal of a relay station.

A method for transmitting an uplink control signal of a relay station may include: setting a UL relay station zone in which a relay station transmits a signal to a base station; Setting a resource unit composed of a plurality of symbols and a plurality of subcarriers for allocating an uplink control signal to a subframe of the UL RS; And transmitting the uplink control signal through the resource unit, and when the subframe includes a switching time required for signal transmission / reception switching of the RS, a plurality of resource units including the switching time. The uplink control signal is transmitted in the remaining symbols except for the symbols.

Since the orthogonality of the uplink control signal transmitted from the relay station to the base station and the uplink control signal transmitted from the terminal to the base station can be maintained to the maximum, interference between the control signals can be reduced. Therefore, the RS can perform reliable uplink control signal transmission.

1 shows a wireless communication system including a relay station.
2 shows an example of a superframe structure.
3 shows an example of a TDD frame structure.
4 shows an example of an FDD frame structure.
5 to 8 show examples of the frame structure including the switching time.
9 shows an example of a TDD frame structure.
10 shows an example of including a switching time in an FDD frame.
11 shows an example of a resource unit used for an uplink control channel.
12 shows an example of resource allocation for an HFBCH.
13 is a flowchart illustrating a control signal transmission method of a relay station according to an embodiment of the present invention.
14 shows an example of configuring an HFBCH in consideration of a switching time.
15 shows another example of configuring an HFBCH in consideration of a switching time.
16 shows an example of resource allocation for a bandwidth request channel.
17 shows the configuration of a relay station and a base station.

The following techniques include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like. It can be used in various wireless communication systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), or the like. IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of Evolved UMTS (E-UMTS) using Evolved-UMTS Terrestrial Radio Access (E-UTRA), which employs OFDMA in downlink and SC in uplink -FDMA is adopted. LTE-A (Advanced) is the evolution of 3GPP LTE.

For clarity, the following description focuses on IEEE 802.16m, but the technical spirit of the present invention is not limited thereto.

1 shows a wireless communication system including a relay station.

Referring to FIG. 1, a wireless communication system 10 including a relay station includes at least one base station 11 (BS). Each base station 11 provides a communication service for a particular geographic area 15, commonly referred to as a cell. The cell can be further divided into a plurality of areas, each of which is called a sector. One or more cells may exist in one base station. The base station 11 generally refers to a fixed station communicating with the terminal 13, and includes an evolved NodeB (eNB), a Base Transceiver System (BTS), an Access Point, an Access Network (AN), It may be called other terms such as ABS (advanced BS). The base station 11 may perform functions such as connectivity, management, control, and resource allocation between the relay station 12 and the terminal 14.

A relay station (RS) 12 refers to a device that relays a signal between the base station 11 and the terminal 14, and includes other relay nodes, repeaters, repeaters, and advanced RS (ARS). It may be called a term. As a relay method used by the relay station, any method such as AF and ADF may be used, and the technical spirit of the present invention is not limited thereto.

The mobile station (MS) 13 or 14 may be fixed or mobile, and may include an advanced mobile station (AMS), a user terminal (UT), a subscriber station (SS), a wireless device, and a personal digital assistant (PDA). It may be called other terms such as an assistant, a wireless modem, a handheld device, an access terminal, and a user equipment (UE). Hereinafter, the macro terminal is a terminal that communicates directly with the base station 11, and the relay station terminal refers to a terminal that communicates with the relay station. Even in the macro terminal 13 in the cell of the base station 11, it is possible to communicate with the base station 11 via the relay station 12 to improve the transmission rate according to the diversity effect.

Downlink (DL) means communication from the base station to the macro terminal between the base station and the macro terminal, and uplink (UL) means communication from the macro terminal to the base station. Downlink between the base station and the relay station means communication from the base station to the relay station, and uplink means communication from the relay station to the base station. The downlink means the communication from the relay station to the relay station between the relay station and the terminal, and the uplink means the communication from the relay terminal to the relay station.

2 shows an example of a superframe structure.

A superframe (SF) includes a superframe header (SFH) and four frames (frames, F0, F1, F2, and F3). Each frame in the superframe may have the same length. The size of each superframe is 20ms and the size of each frame is illustrated as 5ms, but is not limited thereto. The length of the superframe, the number of frames included in the superframe, the number of subframes included in the frame, and the like may be variously changed. The number of subframes included in the frame may be variously changed according to a channel bandwidth and a length of a cyclic prefix (CP).

The superframe header may carry essential system parameters and system configuration information. The superframe header may be located in the first subframe in the superframe. The superframe header may be classified into primary SFH (P-SFH) and secondary SFH (S-SFH; secondary-SFH). P-SFH and S-SFH may be transmitted every superframe.

One frame includes a plurality of subframes (subframe, SF0, SF1, SF2, SF3, SF4, SF5, SF6, SF7). Each subframe may be used for uplink or downlink transmission. One subframe includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and a plurality of subcarriers in the frequency domain. The OFDM symbol is used to represent one symbol period, and may be called another name such as an OFDMA symbol or an SC-FDMA symbol according to a multiple access scheme. The subframe may be composed of 5, 6, 7, or 9 OFDM symbols, but this is only an example and the number of OFDM symbols included in the subframe is not limited. The number of OFDM symbols included in the subframe may be variously changed according to the channel bandwidth and the length of the CP. A type of a subframe may be defined according to the number of OFDM symbols included in the subframe. For example, the type-1 subframe may be defined to include 6 OFDM symbols, the type-2 subframe includes 7 OFDM symbols, the type-3 subframe includes 5 OFDM symbols, and the type-4 subframe includes 9 OFDM symbols. have. One frame may include subframes of the same type. Alternatively, one frame may include different types of subframes. That is, the number of OFDM symbols included in each subframe in one frame may be all the same or different. Alternatively, the number of OFDM symbols in at least one subframe in one frame may be different from the number of OFDM symbols in the remaining subframes in the frame.

A time division duplex (TDD) scheme or a frequency division duplex (FDD) scheme may be applied to the frame. In the TDD scheme, each subframe is used for uplink transmission or downlink transmission at different times at the same frequency. That is, subframes in a frame of the TDD scheme are classified into an uplink subframe and a downlink subframe in the time domain. In the FDD scheme, each subframe is used for uplink transmission or downlink transmission at different frequencies at the same time. That is, subframes in the frame of the FDD scheme are divided into an uplink subframe and a downlink subframe in the frequency domain. Uplink transmission and downlink transmission occupy different frequency bands and may be simultaneously performed.

One OFDM symbol includes a plurality of subcarriers, and the number of subcarriers is determined according to the FFT size. There are several types of subcarriers. The types of subcarriers can be divided into data subcarriers for data transmission, pilot subcarriers for various measurements, guard bands and null carriers for DC carriers. Parameters that characterize an OFDM symbol are BW, N _used , n, G, and the like. BW is the nominal channel bandwidth. N _used is the number of subcarriers _used (including DC subcarriers). n is a sampling factor. This parameter is combined with BW and N _used to determine subcarrier spacing and useful symbol time. G is the ratio of CP time to useful time.

Table 1 below shows OFDMA parameters.

Channel bandwidth, BW (MHz) 5 7 8.75 10 20 Sampling factor, n 28/25 8/7 8/7 28/25 28/25 Sampling frequency, F _s (MHz) 5.6 8 10 11.2 22.4 FFT size, N _FFT 512 1024 1024 1024 2048 Subcarrier spacing, Δf (kHz) 10.94 7.81 9.77 10.94 10.94 Useful symbol time, T _b (μs) 91.4 128 102.4 91.4 91.4 G = 1/8 Symbol time, T _s (μs) 102.857 144 115.2 102.857 102.857 FDD Number of
ODFMA symbols
per 5ms frame 48 34 43 48 48 Idle time (μs) 62.857 104 46.40 62.857 62.857 TDD Number of
ODFMA symbols
per 5ms frame 47 33 42 47 47 TTG + RTG (μs) 165.714 248 161.6 165.714 165.714 G = 1/16 Symbol time, T _s (μs) 97.143 136 108.8 97.143 97.143 FDD Number of
ODFMA symbols
per 5ms frame 51 36 45 51 51 Idle time (μs) 45.71 104 104 45.71 45.71 TDD Number of
ODFMA symbols
per 5ms frame 50 35 44 50 50 TTG + RTG (μs) 142.853 240 212.8 142.853 142.853 G = 1/4 Symbol time, T _s (μs) 114.286 160 128 114.286 114.286 FDD Number of
ODFMA symbols
per 5ms frame 43 31 39 43 43 Idle time (μs) 85.694 40 8 85.694 85.694 TDD Number of
ODFMA symbols
per 5ms frame 42 30 38 42 42 TTG + RTG (μs) 199.98 200 136 199.98 199.98 Number of Guard subcarriers Left 40 80 80 80 160 Right 39 79 79 79 159 Number of used subcarriers 433 865 865 865 1729 Number of PRU in type-1 subframe 24 48 48 48 96

In Table 1, N _FFT is the most small 2 ⁿ in the water is greater than N _used is the least power (Smallest power of two greater than N _used), sampling factor _{F s = floor (n · BW} / 8000) , and × 8000, Subcarrier spacing Δf = F _s / N _FFT , effective symbol time T _b = 1 / Δf, CP time T _g = G · T _b , OFDMA symbol time T _s = T _b + T _g , and sampling time is T _b / N _FFT .

3 shows an example of a TDD frame structure. This represents the case where G = 1/8. The 20 ms long superframe consists of four frames 5 ms long (F0, F1, F2, F3). One frame consists of eight subframes SF0, SF1, SF2, SF3, SF4, SF5, SF6, SF7, and the ratio of the downlink subframe and the uplink subframe is 5: 3. The TDD frame structure of FIG. 3 may be applied when the bandwidth is 5 Mhz, 10 Mhz, or 20 Mhz. SF4, the last downlink subframe, includes 5 OFDM symbols and the remaining subframes include 6 subframes.

4 shows an example of an FDD frame structure. This represents the case where G = 1/8. The 20 ms long superframe consists of four frames 5 ms long (F0, F1, F2, F3). One frame includes eight subframes SF0, SF1, SF2, SF3, SF4, SF5, SF6, SF7, and all subframes include a downlink region and an uplink region. The FDD frame structure of FIG. 4 may be applied when the bandwidth is 5 Mhz, 10 Mhz, or 20 Mhz.

The above-described frame structure may be applied between the base station and the macro terminal. However, when the relay station is included in the wireless communication system, it is difficult to apply the same frame structure to the relay station between the base station and the macro terminal. Since the RS needs to transmit its downlink control information (for example, a preamble or a superframe header (SFH)), the RS needs a radio resource region capable of transmitting a signal to the RS in downlink. In addition, since the RS receives a signal from the RS and decodes the signal and retransmits the signal to the BS, a RS needs a radio resource region capable of transmitting a signal in UL. In addition, the base station also needs a radio resource region capable of receiving a signal in the uplink. In addition, the relay station transmits a signal to a relay station terminal or receives a signal from a base station in the same frequency band. In addition, it receives a signal from the relay station terminal or transmits a signal to the base station in the same frequency band. Thus, the relay station needs a transition gap in switching the transmit / receive operation of the signal. In general, it is assumed that the relay station does not receive or transmit a signal at the switching time. In consideration of this point, a frame structure applicable to a wireless communication system including a relay station may be, for example, as shown in FIGS. 5 to 8.

First we define the term.

In the base station frame, a DL access zone refers to a radio resource region through which a base station transmits a signal to a macro terminal. The DL relay zone refers to a radio resource region in which a base station transmits a signal to a relay station and / or a macro terminal. The UL access zone refers to a radio resource zone where a base station receives a signal from a macro terminal. The UL relay zone refers to a radio resource zone in which a base station receives signals from a macro terminal and / or a relay station.

In the RS frame, the DL access zone refers to a radio resource region through which the RS transmits a signal to the RS. The DL relay zone refers to a radio resource area where a relay station receives a signal from a base station. The UL access zone refers to a radio resource region where a relay station receives a signal from a relay station terminal, and the UL relay station zone refers to a radio resource region where a relay station transmits a signal to a base station.

A transmit / receive transition gap (TGT) is located between the downlink (DL) region and the uplink (UL) region, and a receive / transmit transition gap (RTG) is located between the uplink region and the following frame. The TTG or RTG may include idle time according to the size of the CP to prevent intersymbol interference.

The transition time is either R-TTI or R-RTI. The relay transmit to receive transition interval (R-TTI) may be 1 symbol, which may be inserted between switching of an operation in which a relay station transmits a signal to a relay station terminal and receives a signal from a base station. The relay receive to transmit transition interval (R-RTI) may be 1 symbol, which may be inserted between switching of an operation in which the RS receives a signal from the RS and transmits the signal to the BS. The R-TTI may be set to enable alignment of ARSTTG (ARS Transmit / Receive Transition Gap) and RTD (Round Trip Delay) between the relay station and the superordinate station of the relay station, and the R-RTI is a higher level of the relay station and the relay station. ARSRTG (Receive / transmit transition gap) between the stations and RTD can be set to enable.

5 to 8 show examples of the frame structure including the switching time.

5 shows a frame structure when a switch time is included in a DL access zone.

Referring to FIG. 5, the R-TTI may be inserted into the last symbol of the DL access zone of the relay station frame. 6 shows a frame structure when the switching time is included in the DL reception zone. Referring to FIG. 6, the R-TTI may be inserted into the first symbol of the DL repeater zone of the RS frame. 7 shows a frame structure when the switching time is included in the UL access zone. Referring to FIG. 7, the R-RTI may be inserted into the last symbol of the UL access zone. 8 shows a frame structure when the switching time is included in the UL transmission zone. Referring to FIG. 8, the R-RTI may be inserted into the first symbol of the UL repeater zone.

In FIG. 8, in the 5 symbol subframe including the switching time (UL SF 6), the RS may transmit a signal to the base station using 5 symbols except the first symbol. For example, the RS may puncture and transmit a symbol including the transition time in a subframe including the transition time. On the other hand, the macro terminal may transmit a signal to the base station using a type 1 subframe (6 symbols). Then, the base station receives the type 1 subframe (6 symbols) from the macro terminal, and receives only 5 symbols except the first symbol from the relay station.

9 shows an example of a TDD frame structure.

Referring to FIG. 9, the ratio of the downlink subframe and the uplink subframe is 5: 3. Such a TDD frame structure may be applied to any one of channel bandwidths 5, 10, and 20 MHz, for example, G = 1/8. The number of subframes allocated to the relay station zone in downlink is two, and the number of subframes allocated to the relay station zone in uplink is one. In the TDD frame, in the downlink, a relay transmit to receive transition interval (R-TTI) is included in the last symbol of the DL access zone, and in the uplink, a relay receive to transmit transition interval (R-RTI) is included in the first symbol of the UL relay zone. Can be.

10 shows an example of including a switching time in an FDD frame.

Referring to FIG. 10, in the case of an FDD downlink frame among RS frames, an R-TTI is included in the last symbol of the DL access zone and an R-RTI is included in the first symbol of the UL RS.

However, in the above-described frame structure as shown in FIG. 8, if the RS transmits an uplink control signal through the uplink control channel to the base station in UL subframe 6, there may be a problem because the first symbol cannot be used. First, a method of transmitting an uplink control signal between an uplink control channel and a base station and a terminal will be described.

For example, the uplink control channel of the IEEE 802.16m system includes a fast feedback channel (FFBCH), a hybrid automatic repeat request (HARQ) feedback control channel (HFBCH), and a sounding channel (sounding channel). channel, ranging channel, and bandwidth request channel (BRCH).

The fast feedback channel carries feedback of CQI and / or MIMO information. There are two types of fast feedback channels, a primary fast feedback channel (PFBCH) and a secondary fast feedback channel (SFBCH). The primary fast feedback channel carries 4 to 6 bits of information and provides wideband CQI and / or MIMO feedback. The secondary fast feedback channel carries 7 to 24 bits of information and provides narrowband CQI and / or MIMO feedback. The fast feedback channel may be assigned to a predetermined position defined in the broadcast message. The fast feedback channel may be allocated to the terminal periodically. Feedback information of a plurality of terminals may be multiplexed and transmitted in a time division multiplexing (TDM), frequency division multiplexing (FDM), and code division multiplexing (CDM) scheme through the fast feedback channel. The HARQ feedback channel in which the ACK / NACK signal is transmitted in response to data to which the HARQ technique is applied may start at a predefined offset from the data transmission.

The bandwidth request channel is a channel for requesting radio resources for transmitting uplink data or a control signal to be transmitted by the terminal.

The HARQ feedback channel (HFBCH) is a channel for transmitting an acknowledgment (ACK) / non-acknowledgement (NACK) signal in response to data transmission.

The fast feedback channel, bandwidth request channel, HARQ feedback channel (HFBCH), etc. may be located anywhere in the uplink subframe or frame.

11 shows an example of a resource unit used for an uplink control channel.

The resource unit 300 is a resource allocation unit used for transmission of an uplink control channel and is also called a tile. The tile 300 may be a physical resource allocation unit or may be a logical resource allocation unit. The control channel includes at least one tile 300, and the tile 300 consists of at least one subcarrier in the frequency domain on at least one OFDM symbol in the time domain. The tile 300 refers to a bundle of a plurality of subcarriers adjacent to the time domain and the frequency domain. The tile 300 includes a plurality of data subcarriers and / or pilot subcarriers. A sequence of control signals may be mapped to the data subcarrier, and a pilot for channel estimation may be mapped to the pilot subcarrier.

The tile 300 includes three mini units 310, 320, 330. Mini units are also called mini tiles. The tile 300 may be configured of a plurality of mini-tiles, and the minitile may be configured of at least one subcarrier in the frequency domain on at least one OFDM symbol in the time domain. Each of the mini tiles 310, 320, 330 includes two contiguous subcarriers over six Orthogonal Frequency Division Multiplexing (OFDM) symbols. The minitiles 310, 320, 330 in the tile 300 may not be adjacent to each other in the frequency domain. This means that at least one minitile of another tile may be disposed between the first minitile 310 and the second minitile 320 and / or between the second minitile 320 and the third minitile 330. it means. Frequency diversity may be obtained by distributing the minitiles 310, 320, and 330 in the tile 300 in the frequency domain.

The resource unit may be used as a unit in resource allocation of the feedback channel. That is, the feedback channel may be composed of three mini tiles of 2x6 size. The feedback channel may be configured by allocating a DRU among logical resources. One DRU may consist of three distributed tiles of size 6 × 6, which in turn may be divided into three adjacent mini tiles of size 2 × 6. The mini-tile is a feedback mini-tile (FMT) in that it is a resource unit used for a feedback channel.

The number of OFDM symbols in the time domain and / or the number of subcarriers in the frequency domain included in the minitile is only an example and is not a limitation. The number of OFDM symbols included in the minitile may vary depending on the number of OFDM symbols included in the subframe. For example, if the number of OFDM symbols included in one subframe is six, the number of OFDM symbols included in the minitile may be six.

An OFDM symbol refers to a duration in the time domain and is not necessarily limited to a system based on OFDM / OFDMA. This may be called another name such as a symbol interval, and the technical concept of the present invention is not limited to a specific multiple access scheme by the name of an OFDM symbol. In addition, a subcarrier refers to an allocation unit in the frequency domain. Here, one subcarrier is used as a unit, but a subcarrier aggregation unit may be used.

12 shows an example of resource allocation for an HFBCH.

The resources of the HFBCH exist in three distributed 2 × 6 Feedback Mini-Tiles (FMTs), and each FMT is subdivided into 2 × 2 HARQ Mini-Tiles (HMTs). Can be. That is, in the HFBCH, an HMT group consisting of 3 × 2 HMTs may be a unit of one HFBCH. A pair of HFBCHs is allocated to the HMT group. In addition, orthogonal sequences shown in the following table are mapped to each HMT.

In FIG. 12, (C _{i, 0} , C _{i, 1} , C _{i, 2} , C _{i, 3} , i = 0, 1, 2) means an orthogonal sequence given by the table. Here, i means HMT index. Orthogonal sequences are mapped to each HMT in each HMT group to maintain orthogonality.

If the above method is applied to the relay station in the same manner, there may be a problem in transmitting an uplink control signal. If the first symbol in the UL relay zone zone of the relay station frame is used with a transition time such as R-RTI, the relay station cannot transmit a control signal in the first symbol. Then, the problem is that the HMT assigned to the first symbol and the second symbol may not maintain orthogonality.

In addition, when the HFBCH signals transmitted by the macro terminal and the relay station are multiplexed and transmitted, the base station may receive the HMT in one symbol from the relay station while receiving the HMT in two symbols from the macro terminal.

13 is a flowchart illustrating a control signal transmission method of a relay station according to an embodiment of the present invention.

The relay station receives frame setting information from the base station (S100). The relay station sets the DL access zone, DL relay station zone, UL access zone, and UL relay station zone in the frame using the frame setting information (S110). The RS may set a resource unit composed of a plurality of symbols and a plurality of subcarriers, which allocates an uplink control signal to a subframe of a UL RS. For example, in the case of the HFBCH, the resource unit is a HARQ Mini-Tile (HMT) of 2 × 2 in each of three distributed 2 × 6 Feedback Mini-Tiles (FMT). Can be. In the case of BRCH, 6 × 6 tiles may be a resource unit.

It is determined whether there is a symbol used as a switching time in the UL RS (S120). For example, it may be determined whether the first symbol of the UL relay station zone is used as the switching time.

For example, if there is a symbol used as a switching time in a type 1 UL subframe, only 5 symbols may be used. In this case, the RS configures a control channel in consideration of the switching time (S130). The control channel in consideration of the switching time is a method for transmitting the control channel in a subframe in which only a reduced number of symbols, for example, 5 symbols is available due to the switching time. A method of configuring a control channel in consideration of the switching time will be described later. The relay station transmits a control signal to the base station through the configured control channel (S150).

If the UL relay zone does not include the switching time, the control channel may be configured according to the existing method of configuring the control channel (S140). For example, if the first symbol of the UL relay station zone is not used as the switching time, the relay station may configure the control channel according to the existing control channel configuration method. The existing control channel configuration method may, for example, transmit and allocate resources for the HFBCH according to the method described with reference to FIG. 10 in the case of the HFBCH.

14 shows an example of configuring an HFBCH in consideration of a switching time.

If the first symbol is used as a transition time (eg, R-RTI) in a subframe of the UL relay zone zone, the relay station may transmit only the remaining symbols without transmitting both the first symbol and the second symbol in the first subframe. That is, the HARQ ACK / NACK (acknowledgement / negative acknowledgment) signal may be transmitted in the remaining symbols except for two symbols constituting the resource unit including the symbol in which the switching time is located.

The relay station may arrange HARQ ACK / NACK signals in the resource units of the two symbols, and then may puncture the two symbols and transmit only other symbols in the subframe. Alternatively, the RS may not transmit the two symbols without first placing a HARQ ACK / NACK signal in the resource unit of the two symbols.

As such, when the RS transmits only the remaining symbols except the first two symbols of the UL RS, it is possible to prevent the orthogonality from being broken in the HMT disposed in the first two symbols. If the RS transmits the remaining symbols except only the first one symbol of the UL RS zone used as the switching time, orthogonality by the orthogonal sequence is not maintained in the HMT 1 810 received by the BS. For example, if the HFBCH pair of the macro terminal and the relay station is transmitted to the HMT 1 810, only the HFBCH signal transmitted by the macro terminal is received in the first symbol, and the HFBCH signal transmitted by the macro terminal and the relay station is received in the second symbol. Therefore, orthogonality by orthogonal sequences is not maintained.

In contrast, according to the present invention, since the base station receives only the HFBCH signal transmitted from the macro terminal in the HMT 1 810, the orthogonality is maintained. In addition, since the HMT 2 811 and the HMT 3 812 receive the HFBCH signals transmitted from the macro terminal and the RS while maintaining orthogonality, reliability is increased.

15 shows another example of configuring an HFBCH in consideration of a switching time.

Referring to FIG. 15, the base station may allocate HMT to which the HFBCH is allocated for the UE and HMT to which the HFBCH is allocated for the RS in the time-frequency domain. That is, HFBCHs of the UE and the RS may not be code division multiplexed (CDM) in the same HMT. Then, even if the relay station transmits the remaining symbols except the first symbol in the HMT 1 131, only the orthogonality of the relay station HMT 1 131 is broken, but the HARQ ACK / NACK signal transmitted by the macro terminal from the HMT 1 '132. There is no interference with. The RS may allocate the resource for the HFBCH by receiving control channel allocation information from the base station. In the above description, the HFBCH has been described as an example of the control channel, but this is not a limitation.

In addition, in the above description, for example, with reference to FIGS. 14 and 15, the case where the first symbol of the UL relay station zone is used as the switching time is not limited. For example, the present invention can be applied even when the last symbol of the UL relay zone is used as the switching time. In this case, however, the RS may not transmit the last two symbols in the UL subframe including the switching time. Alternatively, the HFBCH may be transmitted to the base station by allocating radio resources in a time frequency domain different from that of the terminal.

The invention can also be applied to, for example, bandwidth request channels.

16 shows an example of resource allocation for a bandwidth request channel.

The bandwidth request channel may be composed of three BR tiles distributed. The BR tile may be a radio resource region composed of six symbols and six subcarriers. The BR tile may include a preamble area to which a preamble is allocated and a data area to which data is allocated. The preamble may be transmitted through the preamble area, and data may be transmitted through the data area. The preamble region is allocated over six symbols in the time domain and four subcarriers in the frequency domain in each BR tile. The data region is allocated over six symbols in the time domain and two subcarriers in the frequency domain in each BR tile. In FIG. 16, a region marked with Pr may be a preamble region and a region marked with M may be a data region. A bandwidth request channel may not exist in a subframe or may be transmitted up to two.

Scheduling information for the bandwidth request channel, that is, information on which subframe to perform the bandwidth request, period, and which radio resource to use, is transmitted to the relay station or the terminal by the base station through a superframe header or broadcast / multicast signal. Can transmit

However, when some symbols of a relay station frame UL relay station zone, for example, the first symbol or the last symbol of the UL relay station zone are used as R-RTI or R-TTI, the orthogonality of the bandwidth request channel transmitted by the terminal and the bandwidth request channel transmitted by the relay station This is broken and can be a problem.

To solve this problem, the base station may separately allocate the bandwidth request channel region allocated to the terminal and the bandwidth request channel region allocated to the relay station for the uplink subframe including the switching time.

In this case, the terminal may transmit the bandwidth request channel to the base station according to the existing method in the same manner as described with reference to FIG. The RS may transmit the bandwidth request channel through the new bandwidth request channel region allocated from the base station. In the uplink subframes other than the uplink subframe including the switching time in the UL RS, the RS and the UE may maintain orthogonality with each other, and thus may use resource regions on the same time and frequency. That is, if there is more than one uplink subframe in the UL RS zone, the bandwidth request channel of the RS may be allocated to an uplink subframe that does not include a switching time (eg, an R-RTI). In this case, the resource region to which the bandwidth request channel of the RS is allocated may be the same as the resource region to which the bandwidth request channel of the MS is allocated.

Alternatively, the base station may not allocate a bandwidth request channel for the relay station for the uplink subframe including the switching time in the UL relay zone.

Alternatively, the base station may allocate a bandwidth request header dedicated to the relay station to an uplink subframe including the switching time in the UL relay zone. Alternatively, the base station may allocate a bandwidth request header so that the bandwidth request can be made regardless of the switching time. Information such as the period and duration of the bandwidth request header can be received by the relay station by polling the IE message. In general, since the RS transmits the bandwidth request signal more frequently than the UE and the amount of resources required for the bandwidth request channel is large, the BS may allocate the bandwidth request header periodically. This method may be effective when there is only one uplink subframe in the UL relay zone.

17 shows the configuration of a relay station and a base station.

The base station 500 includes a processor 510, a memory 530, and an RF unit 520. The processor 510 allocates radio resources to the relay station and performs scheduling to receive signals from the relay station. Procedures, techniques, and functions performed by the base station among the above-described embodiments may be implemented by the processor 510. The memory 530 is connected to the processor 510 and stores various information for driving the processor 510. The RF unit 520 is connected to the processor 510 to transmit and / or receive a radio signal.

The relay station 600 includes a processor 610, a memory 620, and an RF unit 630. The procedures, techniques, and functions performed by the RS among the above-described embodiments may be implemented by the processor 610. For example, a UL relay station zone in which a relay station transmits a signal to a base station in a relay station frame is set, and a resource unit including a plurality of symbols and a plurality of subcarriers for assigning an uplink control signal to a subframe of the UL relay station zone is set. In addition, an uplink control signal transmitted through a resource unit may be generated and allocated. When the uplink subframe of the UL relay zone zone includes a switching time required for signal transmission / reception switching of the relay station, the uplink control signal may be transmitted in the remaining symbols except for a plurality of symbols constituting a resource unit including the switching time. The memory 620 is connected to the processor 610 and stores various information for driving the processor 610. The RF unit 630 is connected to the processor 610 to transmit and / or receive a radio signal.

Processors 510 and 610 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processing devices. The memories 520 and 620 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media and / or other storage devices. The RF unit 530 and 630 may include a baseband circuit for processing a radio signal. When the embodiment is implemented in software, the above-described techniques may be implemented with modules (processes, functions, and so on) that perform the functions described above. Modules may be stored in the memory 520, 620 and executed by the processors 510, 610. The memories 520 and 620 may be inside or outside the processors 510 and 610, and may be connected to the processors 510 and 610 by various well-known means.

The present invention may be implemented in hardware, software, or a combination thereof. (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microprocessor, and the like, which are designed to perform the above- , Other electronic units, or a combination thereof. In the software implementation, the module may be implemented as a module that performs the above-described function. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

As mentioned above, preferred embodiments of the present invention have been described in detail, but those skilled in the art to which the present invention pertains should understand the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated that various modifications or changes can be made. Accordingly, modifications of the embodiments of the present invention will not depart from the scope of the present invention.

Claims (9)

In the method of transmitting an uplink control signal of a relay station,
Establishing a UL relay station zone in which a relay station transmits a signal to a base station within a frame;
Setting a resource unit composed of a plurality of symbols and a plurality of subcarriers for allocating an uplink control signal to a subframe of the UL RS; And
Transmitting the uplink control signal through the resource unit;
When the subframe includes a switching time required for signal transmission and reception switching of the relay station, the uplink control signal is transmitted in the remaining symbols except for a plurality of symbols constituting a resource unit including the switching time. Method of transmitting an uplink control signal of a relay station. The method of claim 1, wherein the switching time is included in a first symbol or a last symbol of the subframe. The method of claim 1, wherein the resource unit includes two symbols in the time domain and two subcarriers in the frequency domain. The uplink control signal of the relay station according to claim 3, wherein the uplink control signal is a hybrid automatic repeat request (HARQ) acknowledgment / negative acknowledgment (ACK) for data transmitted from the base station to the relay station. Transmission method. The method of claim 4, wherein the uplink control signal is transmitted in symbols other than the first two symbols of the subframe. The method of claim 1, wherein the uplink control signal is a bandwidth request signal. In the method of transmitting an uplink control signal of a relay station,
Establishing a UL relay station zone in which a relay station transmits a signal to a base station within a frame;
Setting a resource unit composed of a plurality of symbols and a plurality of subcarriers for allocating an uplink control signal to a subframe of the UL RS; And
Transmitting the uplink control signal through the resource unit;
When the subframe includes a switching time required for signal transmission and reception switching of the RS, the resource unit has a frequency or time different from that of the UE transmitting an uplink control signal to the BS. Link control signal transmission method. RF unit for transmitting and receiving a radio signal; And
Including a processor connected to the RF unit,
The processor sets a UL relay station zone in which a relay station transmits a signal to a base station within a frame, and assigns a resource unit including a plurality of symbols and a plurality of subcarriers to allocate an uplink control signal to a subframe of the UL relay station zone. And a plurality of symbols constituting a resource unit including the switching time when the uplink control signal is transmitted through the resource unit and the switching time required for signal transmission / reception switching of the RS is included in the subframe. The relay station, characterized in that for transmitting the uplink control signal in the remaining symbols. RF unit for transmitting and receiving a radio signal; And
Including a processor connected to the RF unit,
The processor sets a UL relay station zone in which a relay station transmits a signal to a base station within a frame, and assigns a resource unit including a plurality of symbols and a plurality of subcarriers to allocate an uplink control signal to a subframe of the UL relay station zone. Set and transmit the uplink control signal through the resource unit, if the subframe includes a switching time required for the signal transmission and reception switching of the relay station, the resource unit is the terminal transmits the uplink control signal to the base station A relay station having a frequency or time different from that of a resource unit.

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