JP5010481B2 - Method for supporting automatic retransmission request in OFDMA wireless access system - Google Patents

Description

  The present invention relates to an OFDMA wireless connection system, and more particularly, to an OFDMA wireless connection system that supports an automatic re-transmission request (HARQ) method. Although the present invention is compatible with a wide range of applications, particularly when using a multi-antenna system in an OFDMA radio access system supporting HARQ, signal transfer by multiple antennas through the same uplink or downlink data bursts. It is suitable for reducing the overhead caused by having to retransmit even if there is no transfer error.

  Generally, ARQ (Automatic Repeat Request) refers to a response message that informs whether or not data has been reliably received after the receiving side has received data from the transmitting side in the communication system. ARQ informs the transmitting side whether or not data has been received. There are three ARQ schemes as shown in FIGS. 1A to 1C.

  FIG. 1A shows a 'Stop-and-wait' ARQ scheme, and waits for an ACK or NACK message on the receiving side after data transfer. After that, new data is sent or retransmitted.

  FIG. 1B shows a 'Go-back-N' ARQ scheme in which the transmitting side continuously transfers data regardless of the response on the receiving side. When a NACK signal is received, retransmission is performed again in that order.

  In the 'Selective-repeat' ARQ shown in FIG. 1C, the transmission side continuously transfers data regardless of the response of the reception side. Only the data that received the NACK signal is retransmitted.

  As a data rate is required to be 2 Mbps, 10 Mbps or more in a packet transfer communication system, a higher coding rate, a higher-order modulation method, etc. (Rc = 5/6, 3 / 4, Mod = 16−QAM, 64−QAM) is selected, and this causes a larger error on the channel. However, a technique proposed as one method for solving this problem is HARQ. (Hybrid ARQ).

  In the HARQ method, data in which an error has occurred is stored in a buffer, and FEC (Forward Error Correction) is applied in combination with information to be retransmitted. On the other hand, in the ARQ method, data in which an error occurs during transfer is discarded. That is, the HARQ scheme can be said to be a scheme combining FEC and ARQ. HARQ is roughly classified into the following four.

  As shown in FIG. 2, the first method is a Type I HARQ method, in which data is always attached to an error detection code and FEC is preferentially detected. If there is still an error in the packet, a retransmission is requested. Packets with errors are discarded and retransmitted packets are used with the same FEC code.

  The second method is the Type II HARQ method shown in FIG. 3, which is a method called IARRQ (Incremental Redundancy ARQ). In this case, the packet in which an error has occurred is stored in a buffer without being discarded, and is combined with the retransmitted redundancy bits. At the time of retransfer, only the parity bits excluding the data bits are retransferred. The parity bit to be retransmitted is different at each retransfer.

  The third method is the Type III HARQ method shown in FIG. 4, which is a special case of Type II, and each packet can be decoded by itself (self-decoding). The re-transfer is configured as a packet including both the portion where the error has occurred and the data, and the re-transfer is performed. Although this method enables more accurate decoding than Type II, it is disadvantageous in terms of coding gain.

  The fourth method is a “Type I with soft combining” method shown in FIG. 5, and the Type I function has a function of storing data received for the first time on the receiving side and combining with the retransmitted data. It is an added method. The 'Type I' HARQ scheme combined with 'soft combining' is also called metric combining or chase combining. This method has gain in SINR, and always uses the same parity bit for retransmitted data.

  In recent years, OFDM (Orthogonal Frequency Division Multiplexing) or OFDMA (Orthogonal Frequency Division Multiplexing Access) has been actively studied as a method suitable for high-speed data transfer over wired and wireless channels. In the OFDM system, frequency utilization efficiency is increased because a plurality of carriers having mutual orthogonality are used. The processes of modulating / demodulating such a plurality of carriers at the transmission / reception end are the same as those performed by IDFT (Inverse Discrete Fourier Transform) and DFT (Discrete Fourier Transform), respectively. IFFT (Inverse Fast Fourier Transform) It can be implemented at high speed using a Fourier Transform.

  The principle of OFDM is to divide a high-speed data stream into a plurality of low-speed data streams and simultaneously transmit them using a plurality of subcarriers, thereby increasing a symbol duration, and a multipath delay spread (multiple). -Reducing relative dispersion in the time domain due to path delay spread. Data transfer by the OFDM method is performed in units of transfer symbols.

  Modulation / demodulation in the OFDM system can be collectively processed for all subcarriers using DFT (Discrete Fourier Transform), so that it is not necessary to design a modulator / demodulator for each individual subcarrier.

  FIG. 6 is a diagram showing a conceptual configuration of an OFDM system modulator / demodulator. As shown in FIG. 6, the serially input data stream is converted into parallel data streams corresponding to the number of subcarriers, and each parallel data stream is subjected to inverse discrete Fourier transform. An IFFT (Inverse Fast Fourier Transform) is used for high-speed data processing. The data subjected to the inverse discrete Fourier transform is converted again into serial data and transmitted through frequency conversion. The receiving side receives the signal and demodulates it in the reverse process.

  The resource in the mobile communication system is a frequency channel, that is, a frequency band. Multiple access is a methodology for efficiently allocating and using a finite frequency band between users. Multiplexing (Duplexing) is a connection methodology that distinguishes connection between UL (UpLink) and DL (DownLink) in bidirectional communication. Wireless multiple access and multiplexing systems are the most fundamental platform technology for wireless transfer technology for efficient use of limited frequency resources. Allocated frequency band, number of users, transfer rate, mobility , Determined by cell structure, wireless environment and the like.

  OFDM (Orthogonal Frequency Division Multiplexing) is a multi-carrier transmission / modulation (MCM) system that uses several carriers, and the input data is parallelized by the number of carriers used, according to the number of carriers used. This is a method of transferring on a carrier wave. OFDM is emerging as a potential wireless transfer technology candidate that satisfies the required characteristics of 4th generation mobile communications, and can be divided into OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA depending on the user's multiple access scheme. Each method has advantages and disadvantages, and there are methods to supplement each disadvantage.

  Among these, OFDM-FDMA (OFDMA) is a method adapted to the 4th generation macro / micro cellular infrastructure, has no intra-cell interference, high frequency reuse efficiency, and is excellent in adaptive modulation and granularity. In addition, in order to compensate for the disadvantages of OFDM-FDMA, diversity can be increased by using a distributed frequency jump method, a multi-antenna method, a powerful encoding method, and the like, and the influence of inter-cell interference can be reduced. In the OFDMA scheme, resource allocation can be efficiently achieved by assigning different numbers of subcarriers according to the transfer rate requested by each user, and before receiving data for each user as in OFDM-TDMA. Since there is no need to initialize using the preamble, the transfer efficiency increases. In particular, the OFDMA scheme is suitable for a case where a large number of subcarriers are used (that is, when the FFT size is large). Therefore, the OFDMA scheme is suitable for a wireless communication system having a wide area cell with a relatively large time delay spread (Time Delay Spread). Applied efficiently. In addition, the frequency-hopping OFDMA scheme overcomes this when there is a subcarrier that has been deeply faded in a radio channel or when there is subcarrier interference by another user. Used to enhance diversity effect and obtain interference average effect. FIG. 6 illustrates an OFDMA scheme in which a frequency allocated hop in a frequency domain is performed by a time slot.

  FIG. 7 is a diagram illustrating a data frame configuration in a conventional OFDMA wireless communication system. In FIG. 7, the horizontal axis is the time axis and is displayed in symbol units, and the vertical axis is the frequency axis and is displayed in subchannel units. The subchannel means a bundle of a plurality of subcarriers. More specifically, in the OFDMA physical layer, active carriers are separated into groups and transmitted to different receiving ends for each group. A group of carriers transferred to one receiving end in this way is referred to as a subchannel. At this time, the carrier waves constituting each subchannel can be adjacent to each other or separated at equal intervals.

  As shown in FIG. 7, a slot assigned to each user is defined by a data region (Data Region) in a two-dimensional space, which is a set of continuous subchannels assigned by a burst. It is. In OFDMA, one data region is schematized in a rectangular shape determined by time coordinates and subchannel coordinates, as shown in FIG. Such a data area can be allocated to the uplink of a specific user. On the downlink, the base station can transfer the data area to a specific user.

  In the prior art of the OFDM / OFDMA wireless communication system, when there is data to be transmitted to a terminal (MSS), a base station (BS) allocates a data area to be transmitted through DL-MAP (Downlink-MAP). The terminal receives data through the allocated area (DL burst # 1 to # 5 in FIG. 7).

  In FIG. 7, a downlink subframe starts with a preamble used for synchronization and equalization in the physical layer, and then defines the position and usage of bursts allocated to the downlink and uplink. The structure for the entire frame is defined through a downlink MAP (DL-MAP) message and an uplink MAP (UL-MAP) message in broadcast form.

  The DL-MAP message defines the usage assigned to each downlink section in the burst mode physical layer, and the UL-MAP message defines the use of the burst assigned to the uplink section. Information elements (IE: Information Element) constituting DL-MAP are determined by DIUC (Downlink Interval Usage Code), CID (Connection ID), and burst position information (subchannel offset, symbol offset, number of subchannels, number of symbols). The downlink traffic section is divided at the user end. On the other hand, the use of the information elements constituting the UL-MAP message is determined by the UIUC (Uplink Interval Usage Code) for each CID (Connection ID), and the position of the corresponding section is defined by ‘duration’. Here, the use for each section is determined by the UIUC value used in the UL-MAP, and each section starts from a point separated by “duration” defined by the UL-MAP IE from the previous IE start point.

  A DCD (Downlink Channel Descriptor) message and a UCD (Uplink Channel Descriptor) message are respectively a modulation type and FEC code type (FEC) as physical layer related parameters applied in a burst section allocated to a downlink and an uplink. Code type). In addition, necessary parameters (for example, K of R-S Code, R value, etc.) are defined by various types of forward error correction codes. These parameters are given by a burst profile defined for each of UIUC (Uplink Interval Usage Code) and DIUC (Downlink Interval Usage Code) in UCD and DCD, respectively.

  In the OFDMA communication system, the burst allocation scheme can be classified into a general MAP scheme and a HARQ scheme depending on whether the HARQ scheme is supported.

  As shown in FIG. 7, the burst allocation method in the general MAP in the downlink is a quadrangle composed of a time axis and a frequency axis. That is, the start symbol number (symbol offset), the start subchannel number (subchannel offset), the number of symbols used and the number of subchannels used (No. OFDMA symbols, No. Subchannels) are taught. In the uplink, since a method of sequentially assigning to the symbol axis is used, if only the number of symbols used is taught, uplink bursts can be assigned.

  FIG. 8 is a diagram illustrating a data frame based on HARQMAP. Unlike general MAP, HARQ MAP uses a scheme in which both uplink and downlink are assigned in order along the subchannel axis. In HARQMAP, only the burst length is notified. In this method, bursts are allocated sequentially as shown in FIG. The start position of the burst is the position where the previous burst ends, and occupies radio resources for the length allocated from the start position. The method described below relates to a method of allocating bursts in a cumulative manner along the frequency axis, and the method of allocating along the time axis is based on the same principle.

  In addition, in HARQMAP, MAP messages can be divided into several pieces (see FIG. 8: HARQMAP # 1, # 2,..., #N), and each MAP message can have information on an arbitrary burst. . For example, MAP message # 1 may include information on burst # 1, MAP message # 2 may include information on burst # 2, and MAP message # 3 may include information on bursts # 3 to # 5.

  As described above, HARQMAP is used to support HARQ in the OFDMA system. HARQMAP uses a method in which a HARQMAP pointer (pointer) IE is included in DLMAP, and when a HARQMAP position is notified, bursts are sequentially allocated to subchannel axes of downlinks using HARQMAP. The start position of the burst is the position where the previous burst ends, and occupies radio resources for the length allocated from the start position. This also applies to the uplink.

  In addition to this, HARQMAP has to notify control information. Table 1 shows the data format of the HARQ control IE for informing the control information.

前記制御情報にはＡＩ＿ＳＮ、ＳＰＩＤ、ＳＣＩＤなどがあるが、ＡＩ＿ＳＮは、同じＡＲＱチャネルでバーストの転送が成功した時、‘０’と‘１’間にトグル（ｔｏｇｇｌｅ）されて送信するバーストが、新しいバーストか以前のバーストを再転送するものかを知らせる値である。ＨＡＲＱ転送のために各バーストに挿入されるデータビット（ｄａｔａ ｂｉｔｓ）当たり４種類のリダンダンシビット（ｒｅｄｕｎｄａｎｃｙ ｂｉｔｓ）をおくが、ＳＰＩＤは再転送時ごとに異なるリダンダンシビットを選択するための値であり、ＳＣＩＤはＨＡＲＱチャネルＩＤである。

The control information includes AI_SN, SPID, SCID, etc. The AI_SN is a burst that is toggled between '0' and '1' when the burst transfer is successful on the same ARQ channel, It is a value indicating whether a new burst or a previous burst is to be retransmitted. Four types of redundancy bits (redundancy bits) are set for each data bit (data bits) inserted in each burst for HARQ transfer. SPID is a value for selecting a different redundancy bit for each retransmission. SCID is the HARQ channel ID.

  An ACK / NACK signal is used to inform the uplink ACK signal region (ACK Signal Region) whether or not the transferred data burst has been successfully received. If the terminal receives a burst in the i-th frame, the ACK / NACK signal is sent to the uplink ACK signal area of the (i + j) -th frame. The j value is sent by UCD. As a method of assigning an ACK signal area, a method of assigning an ACK signal area to an uplink for each HARQMAP message, and two or more HARQMAP messages among several HARQMAP messages of a frame use one ACK signal area. There is a way.

  A method for informing the slot (ACK) of the burst ACK / NACK signal indicated by the HARQMAP message in order, with one HARQACK area of the frame defined as one, will be described in detail.

  FIG. 9 is a diagram for explaining an HARQ signal area allocation method in the HARQ MAP message. In the HARQMAP message, the ACK signal area is allocated to the uplink using four pieces of information (OFDMA Symbol offset, Subchannel offset, No. OFDMA Symbols, No. Subchannels) of the start position and size of the ACK signal area. Each terminal sequentially inputs an ACK / NACK signal indicating whether or not each burst has been successfully received into an ACK signal area (FIG. 9) allocated to the uplink. The start position of the ACK / NACK signal is the next position after the previously received ACK / NACK information. The order of the ACK / NACK signal follows the burst order of the downlink in the HARQMAP message. That is, in the order from burst # 1 to # 7, ACK / NACK signals in the uplink HARQ ACK area already allocated are also sent in the order corresponding to the bursts from # 1 to # 7.

  As shown in FIG. 9, MAP Message # 1 includes allocation information for bursts # 1 and # 2, MAP Message # 2 includes allocation information for bursts # 3 and # 4, and MAP Message # 3 is The allocation information for bursts # 5 to # is included. MSS # 1 reads the information of burst # 1 in the contents of MAP Message # 1, and the first in the ACK signal area indicating whether or not the transferred data has been successfully received is indicated in the HARQ MAP message. Tell the slot. MSS # 2 informs the next order of the ACK / NACK signal slot of burst # 1 within the ACK signal area. (In the contents of MAP message # 1, the count in burst # 1 is incremented by 1 to determine the position in the HARQACK area.) MSS # 3 calculates the total count of bursts # 1 and # 2 in MAP Message # 1. By calculating, the position within the HARQACK area is known. In this manner, the positions in all HARQACK areas can be known sequentially.

  At this time, if one terminal supports multiple antennas in the downlink burst area and sends data in the same area or multiple terminals send data in the same area, all layers (layers) ) Is sent only when there is no error in the CRC. Otherwise, a NACK signal is sent. Here, a layer means a unit of coding of transferred data, and can have 1 to the number of antennas. For example, when coding the entire data to be transferred and inserting CRC, and dividing this by the number of antennas and transferring through all antennas, the number of layers is one, and the data placed on each antenna is When coding is performed and CRC is inserted, the number of layers becomes the same as the number of antennas (see FIG. 10). Even when the terminal transfers the burst on the uplink, the base station receives the burst, and sends the ACK signal on the downlink, the above situation is applied as it is.

  The conventional technology as described above can be easily applied when the system is not a multi-antenna system. However, when the conventional technology is applied to a multi-antenna system, resources are wasted. For example, when two terminals place their own data in burst # 2, the number of layers is two. As a result of detection at the base station, if there is no error in the burst of the terminal # 1, but there is an error in the burst of the terminal # 2, the two terminals according to the above-mentioned principle, namely, the terminals # 1, # 2 NACK signal is sent to both of them. Therefore, data must be sent to both terminals, and as a result, the data of terminal # 1 must be discarded and retransmitted despite being transferred without error, resulting in a waste of resources. Such a problem in the uplink also occurs in the downlink.

  The present invention relates to transmitting packet data in a wireless communication system configured to support multiple inputs and outputs.

  Additional advantages, objects, and features of the present invention will be set forth in part in the following detailed description, and in part will be apparent to those of ordinary skill in the art based on the description below. It becomes clear from the implementation of. The objects and other advantages of the invention will be realized and attained by the structure pointed out in the written description and claims hereof as well as the appended drawings.

  In order to obtain the above objects and other advantages, and in accordance with an object of the invention, as one embodiment of the invention broadly described herein, a wireless communication configured to support multiple inputs and outputs. A method of transmitting packet data in a system includes: a plurality of data bursts including a plurality of layers each encoded by a corresponding channel encoder; and a plurality of reception confirmation status channel allocation information corresponding to each of the plurality of layers. Receiving a downlink data frame including a data map information element configured to provide multiple antennas capable of providing space-time transmit diversity and providing control information of each of the layers, and uplink The corresponding layer of the plurality of layers is accurately decoded through the data frame. Comprising the step of transmitting a plurality of acknowledgment condition associated with whether or not the ring.

  In one aspect of the present invention, the control information of each of the plurality of layers selects a traffic interval, a channel identifier, a retransmission status, and a different redundancy bit during retransmission. At least one of the values to be selected (difference to select a differential redundancy bit duration retransmission).

  In another aspect of the present invention, the channel encoder includes a forward error correction (FEC) encoder.

  In still another aspect of the present invention, the data map information element includes a HARQ map information element.

  In still another aspect of the present invention, a half subchannel is used for the plurality of acknowledgment states.

  In still another aspect of the invention, at least a part of the plurality of reception confirmation states is expressed by a code word.

  In still another aspect of the present invention, the data map information element is either an uplink map information element or a downlink map information element.

  According to another embodiment of the present invention, a method for transmitting packet data in a wireless communication system configured to support multiple input / output includes the acknowledgment information channel allocation information corresponding to each of a plurality of layers. Receiving a first downlink data frame including a data map information element configured to support multiple antennas capable of providing space-time transmit diversity and providing control information of each of the layers, through the uplink data frame Transmitting a data burst including the plurality of layers, each layer encoded with a corresponding channel encoder, and each acknowledgment state indicating that the corresponding layer of the plurality of layers has been correctly decoded. A first including a plurality of acknowledgment states associated with the no Ri comprises receiving the line data frame.

  In one aspect of the present invention, the control information of each of the plurality of layers selects a traffic interval, a channel identifier, a retransmission status, and a different redundancy bit during retransmission. At least one of the values to be selected (difference to select a differential redundancy bit duration retransmission).

  In another aspect of the present invention, the channel encoder includes a forward error correction (FEC) encoder.

  In still another aspect of the present invention, the data map information element includes a HARQ map information element.

  In still another aspect of the present invention, a half subchannel is used for the plurality of acknowledgment states.

  In still another aspect of the present invention, at least a part of the plurality of reception confirmation states is expressed by a code word.

  In still another aspect of the present invention, the data map information element is either an uplink map information element or a downlink map information element.

  In yet another embodiment of the present invention, a method for transmitting packet data in a wireless communication system configured to support multiple input / output includes data comprising a plurality of layers, each layer encoded with a corresponding channel encoder. Providing control information of each of the plurality of layers including burst and acknowledgment information channel allocation information corresponding to each of the plurality of layers, and configured to support multiple antennas capable of obtaining space-time transmit diversity; A plurality of data map information elements, and a plurality of data related to whether or not a corresponding layer of the plurality of layers is correctly decoded through the uplink data frame. Receiving from the receiving side the reception confirmation status of Including the.

  In one aspect of the present invention, the control information of each of the plurality of layers selects a traffic interval, a channel identifier, a retransmission status, and a different redundancy bit during retransmission. At least one of the values to be selected (difference to select a differential redundancy bit duration retransmission).

  In another aspect of the present invention, the channel encoder includes a forward error correction (FEC) encoder.

  In another aspect of the present invention, the data map information element includes a HARQ map information element.

  Preferably, the method further comprises the step of retransmitting data associated with the corresponding layer upon receipt of an acknowledgment from the receiver indicating the layer that was not correctly decoded.

  In another aspect of the present invention, a half subchannel is used for the plurality of acknowledgment states.

  In still another aspect of the present invention, at least a part of the plurality of reception confirmation states is expressed by a code word.

  In still another aspect of the present invention, the data map information element is either an uplink map information element or a downlink map information element.

  In still another embodiment of the present invention, a wireless communication apparatus for transmitting packet data includes a plurality of antennas for obtaining space-time diversity, a plurality of channel encoders connected to corresponding antennas among the plurality of antennas, and Providing control information for each of the plurality of layers including data bursts including a plurality of layers encoded by corresponding channel encoders, and allocation confirmation channel information corresponding to each of the plurality of layers. And control data frame transmission, including data map information elements configured to support multiple antennas capable of obtaining space-time transmit diversity, and corresponding layers of the plurality of layers are accurately decoded. Multiple confirmation statuses related to Controlling the no-data frame reception comprises a controller.

  In the aspect of the present invention, the control information of each of the plurality of layers selects a traffic interval, a channel identifier, a retransmission status, and a different redundancy bit during retransmission. At least one of the values to be selected (difference to select a differential redundancy bit duration retransmission).

  In another aspect of the present invention, the channel encoder includes a forward error correction (FEC) encoder.

  In still another aspect of the present invention, the data map information element includes a HARQ map information element.

  In still another aspect of the present invention, a half subchannel is used for the plurality of acknowledgment states.

  In still another aspect of the present invention, at least a part of the plurality of reception confirmation states is expressed by a code word.

  In still another aspect of the present invention, the data map information element is either an uplink map information element or a downlink map information element.

  These and other objects, features, shapes and advantages of the present invention will become more apparent from the following detailed description of the present invention based on the accompanying drawings. The foregoing general description of the invention and the following detailed description are both exemplary and explanatory, and the claims provide additional description of the invention.

  The present invention is applicable to a wireless communication system such as a wide area wireless connection system, a mobile communication system, or a mobile internet system.

  The present invention relates to an OFDMA wireless connection system, and more particularly, to an OFDMA wireless connection system that supports an automatic re-transmission request (HARQ) method. In particular, the present invention relates to transmitting packet data in a wireless communication system configured to support multiple input / output.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference numerals as much as possible.

  The present invention discloses a method for transmitting an ACK or NACK signal for each layer in an uplink or downlink data burst to which a multi-antenna system is applied. In other words, for the uplink or downlink data burst to which the multi-antenna system is applied, ACK / NACK signal transfer channels corresponding to the number of layers allocated to the data burst are allocated.

  When one terminal supports multiple antennas and transmits data in the same area in the downlink burst area, or when multiple terminals transmit data in the same area, all layer signals are sent to the same area. Can be placed. In this case, the signal on each layer can be distinguished by detection on the receiving side. Then, the CRC of each layered signal is checked to check whether there is an error in each layer signal.

  In this way, the present invention is to notify the transmitting side of the presence or absence of errors in the signals for each layer by transferring ACK or NACK signals. In order to support this, it is necessary to assign an ACK or NACK channel for each layer in order to transmit the presence / absence of errors in the signals for each layer. The side transmitting the burst through these channels can receive an ACK or NACK signal for each layer, and determines the next transfer method based on the signal. For example, the signal of the layer that received the NACK is retransmitted, and the signal of the layer that received the ACK is stopped until the other layer receives the ACK signal according to the system implementation method to reduce interference with other signals it can.

  The amount of transfer can be increased by placing other waiting data. Thus, in order to use a different transfer method for each layer, control information must be given to each layer. That is, conventionally, all layers receive ACK or NACK together, and thus control information is collectively given together. However, in the method of the present invention, whether ACK or NACK is received for each layer, respectively. Depending on whether or not to give a new burst or retransmit the previous burst (AI_SN), it is necessary to determine which of the four types of redundancy bits (SPID) and H-ARQ channel ID (SCID). I must.

  FIG. 11 is a diagram illustrating a data frame in an OFDMA wireless access system according to a preferred embodiment of the present invention. FIG. 5 is a diagram for explaining an embodiment of a method for assigning an ACK / NACK transfer channel by a base station that applies a multi-antenna system and transfers data to a plurality of terminals by two layers.

  In FIG. 11, the base station allocates a downlink ACK signal area (DL-ACK SIGNAL REGION) to the downlink (DL) subframe, and an uplink ACK signal area (UL-ACK SIGNAL REGION) to the uplink (UL) subframe. ). The downlink ACK signal area is an area allocated for an ACK or NACK signal transferred by the base station in response to data transferred by a plurality of terminals. The uplink ACK signal area is an area allocated for ACK or NACK signals transferred by the plurality of terminals as a response to data transferred by the base station.

  When the base station transfers data bursts by two layers (2-layer), the terminal receiving the data bursts by these two layers checks the transfer error of the data transferred for each layer of the base station. (For example, CRC check). As a result, if there is no transfer error for each layer, the ACK signal is transferred, and if there is a transfer error, the NACK signal is transferred. One ACK / NACK transfer channel is allocated to a terminal that receives a data burst transferred in one layer by the base station. As a result, for each terminal, the same number of ACK / numbers as the number of layers used by the base station to transfer each data burst to the uplink ACK signal area of the uplink sub-frame (uplink sub-frame). Assign NACK transfer channels (# 1-1, # 1-2, # 2-1, # 2-2, # 3, # 4,...).

  In the downlink ACK signal area, the base station allocates ACK / NACK transfer channels (# 2-1, # 2-2) for each layer to terminals that transfer data by two layers. One ACK / NACK transfer channel (# 1, # 3, # 4,...) Is assigned to a terminal that uses. The base station checks a transfer error for the data transferred from the terminal (for example, CRC check). As a result, if there is no transfer error for each layer, the ACK signal is transferred, and if there is a transfer error, the NACK signal is transferred.

  The ACK / NACK transfer channel may be assigned in order to the time axis in the uplink ACK signal area and the downlink ACK signal area, may be assigned in order to the frequency axis, or alternately assigned to the frequency axis and the time axis. May be. Conventionally, a half subchannel is used for each ACK or NACK signal, and they are assigned alternately to the frequency axis and the time axis, that is, in the order shown in FIG. The half subchannel consists of 24 subcarriers.

  FIG. 13 is a diagram illustrating another scheme for assigning the ACK / NACK transfer channel in the uplink ACK signal area and the downlink ACK signal area. Preferably, FIG. 13 is a diagram illustrating an example in which uplink or downlink ACK areas are individually assigned to terminals to which a multiple antenna system is applied in the uplink ACK signal area and the downlink ACK signal area.

  Referring to FIG. 13, the ACK / NACK transfer channel (# 2-1) for the first layer is for a terminal that transfers data bursts by two layers (2-layer) in the downlink ACK area. Allocated with an ACK / NACK transport channel for terminals transferring data bursts by one layer. For terminals that transfer data bursts by the two layers (2-layer), the ACK / NACK transport channel (# 2-2) for the second layer is another ACK in the downlink ACK area. Set and assign a region. Preferably, the same method is also applied to the uplink ACK area (UL-ACK region).

  In FIG. 13, the base station transfers HARQDL burst # 2 using four layers (4-layer). The another ACK area allocated to the second or higher layer is preferably allocated next to the area where the ACK / NACK transport channel for the first layer is allocated.

  FIG. 14 is a diagram illustrating another example of a scheme for assigning the ACK / NACK transfer channel in the uplink ACK signal area and the downlink ACK signal area.

  In FIG. 14, the uplink or downlink ACK area is individually assigned to the terminal to which the multi-antenna system is applied in the uplink ACK signal area and the downlink ACK signal area, as in the example of FIG. However, in the method of FIG. 14, a plurality of ACK / NACK transfer channels (# 2-2, # 2-3, # 2-4) for the same data burst to which a plurality of layers are applied are converted into codewords. Is different from that shown in FIG. 13 in that it is assigned to one ACK / NACK transfer channel. In other words, in the embodiment shown in FIG. 14, when the number of layers increases, the range of the uplink ACK area may be excessively expanded, and thus a code word is used to reduce the range.

  Tables 2 and 3 exemplify code words for supporting FIG.

上り回線ＡＣＫ／ＮＡＣＫ信号の転送においては、前述したように、ＡＣＫまたはＮＡＣＫ信号１つ当たりに２４個の副搬送波からなるハーフサブチャネル（ｈａｌｆ ｓｕｂｃｈａｎｎｅｌ）を使用するが、表２及び表３のようなコードワードを使用すると、２４個の副搬送波を用いて３つまでのＡＣＫまたはＮＡＣＫ信号を転送できる。表２及び表３の例は、４つのレイヤーのためのコードワードを定義したもので、これは２つまたは３個のレイヤーに対しても適用可能である。すなわち、３つのレイヤーの適用されたデータバーストに対しては表２及び表３においてレイヤー４に関するものを無視し、２つのレイヤーの適用されたデータバーストに対してはレイヤー４及びレイヤー３に関するものを無視すればよい。

In the uplink ACK / NACK signal transfer, as described above, a half subchannel consisting of 24 subcarriers per ACK or NACK signal is used, but as shown in Tables 2 and 3 Using a simple codeword, up to 3 ACK or NACK signals can be transferred using 24 subcarriers. The examples in Table 2 and Table 3 define codewords for four layers, which can be applied to two or three layers. That is, for data bursts applied to three layers, ignore those related to layer 4 in Tables 2 and 3, and for data bursts applied to two layers, those related to layers 4 and 3 Ignore it.

  On the other hand, in the case of the downlink, as in the conventional method, when an ACK / NACK signal is transferred using one bit, the necessity of using a code word is reduced.

  FIG. 15 is a diagram illustrating still another example of a scheme for assigning the ACK / NACK transfer channel in an uplink ACK signal area and a downlink ACK signal area.

  Referring to FIG. 15, ACK areas for terminals using data bursts applied in a multi-antenna system are individually allocated in the same manner as in FIG. 13 or FIG. In the remaining uplink or downlink ACK area, an ACK signal is sent only when there is no error in the CRC for all layers as in the conventional method, and a NACK signal is sent otherwise. Assign a NACK transfer channel.

  Tables 4 and 5 show the formats of the MIMO compact DL-MAP IE and the MIMO compact UL-MAP IE, respectively, according to a preferred embodiment of the present invention.

従来の情報要素（ＩＥ）は、各レイヤーごとに制御情報を別に置くことができず、本発明を支援できない。したがって、ＨＡＲＱ多重アンテナを支援するための情報メッセージ（ＭＩＭＯ Ｃｏｍｐａｃｔ ＤＬ／ＵＬ ＭＡＰ ＩＥ）に、各レイヤーごとにそれぞれＡＣＫまたはＮＡＣＫを受信するかによって、新しいバーストを与えるかまたは以前のバーストを再転送するか（ＡＩ＿ＳＮ）を表す情報、４種類のうちの何番目のリダンダンシビットを与えるか（ＳＰＩＤ）を表す情報、及びＨ−ＡＲＱチャネルＩＤ（ＳＣＩＤ）の情報を含む制御情報が与えられる場合に限って、各レイヤーごとに異なる動作が可能になる。前記制御情報は、必要によって直接ＨＡＲＱ多重アンテナを支援するための情報メッセージ（ＭＩＭＯ Ｃｏｍｐａｃｔ ＤＬ／ＵＬ ＭＡＰ ＩＥ）にフィールドを置いても良く、実施例のように既存の‘Ｃｏｎｔｒｏｌ＿ＩＥ’という情報要素をＨＡＲＱ多重アンテナを支援するための情報メッセージ（ＭＩＭＯ Ｃｏｍｐａｃｔ ＤＬ／ＵＬ ＭＡＰ ＩＥ）に挿入する方式でも使用可能である。

The conventional information element (IE) cannot place control information separately for each layer, and cannot support the present invention. Therefore, in the information message (MIMO Compact DL / UL MAP IE) for supporting the HARQ multiple antenna, a new burst is given or a previous burst is retransmitted depending on whether ACK or NACK is received for each layer. Only when control information including information indicating (AI_SN), information indicating which of the four types of redundancy bits is provided (SPID), and H-ARQ channel ID (SCID) information is provided. , Different operation is possible for each layer. The control information may include a field in an information message (MIMO Compact DL / UL MAP IE) for directly supporting a HARQ multiple antenna as necessary, and an existing information element of 'Control_IE' may be added to the HARQ as in the embodiment. It is also possible to use a method of inserting into an information message (MIMO Compact DL / UL MAP IE) for supporting multiple antennas.

  According to the present invention, when signals are transmitted by a plurality of antennas through the same uplink or downlink data burst in a multi-antenna system, ACK or NACK signals can be transferred for each layer. Thus, the present invention can reduce the overhead that results from having to retransmit even though there are no transfer errors.

  Although the present invention has been described in mobile communication, the present invention can be used in any wireless communication system that uses a mobile device such as a notebook equipped with a PDA and wireless communication equipment.

  More preferred embodiments can be embodied as a method, apparatus, or manufacturing method apparatus that utilizes standard programming and / or engineering techniques to produce software, firmware, hardware, or some combination. The terminology of the manufacturing method includes hardware logic (for example, an integrated circuit chip, a field programmable gate array (FPGA), an application specific integrated circuit (Application Specific Integrated Circuit), and the like. Or computer readable media (eg, magnetic storage medium (eg, hard disk drive, floppy disk tape, etc.), optical storage ( CD-ROMs, optical disks, etc.), volatile / non-volatile Sexual storage device (e.g., EEPROMs, ROMs, PROMs, RAMs, DRAMs, SRAMs, firmware, programmable logic, etc.) and the like.

  Code contained in the computer readable medium is accessed and executed by a processor. The code executed in a more preferred embodiment may be accessible from a file server through a transfer medium or network. The manufacturing method in which the code is executed may include signal transmission through a network transfer line, wireless transfer media, space, radio wave, infrared signal, and the like. Of course, it will be apparent to those skilled in the art how to make this configuration without departing from the scope of the present invention, many applications and manufacturing methods that can include any improved medium known in the prior art. It is. Preferably, as shown in FIG. 10, the present invention can be implemented with a mobile communication apparatus including the above-described processor together with a plurality of antennas and channel encoders, and the configuration shown in FIG.

  It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the invention. The scope of the present invention includes any modifications of the present invention that can be provided within the scope of the appended claims and the equivalent scope of the present invention.

It is a figure for demonstrating the characteristic by the kind of ARQ system. It is a figure for demonstrating the characteristic by the kind of ARQ system. It is a figure for demonstrating the characteristic by the kind of ARQ system. It is a figure for demonstrating the characteristic by the kind of HARQ system. It is a figure for demonstrating the characteristic by the kind of HARQ system. It is a figure for demonstrating the characteristic by the kind of HARQ system. It is a figure for demonstrating the characteristic by the kind of HARQ system. It is a figure which shows the notional structure of the OFDM system modulator / demodulator. It is a figure which shows the structure of the data frame in the conventional OFDMA radio | wireless communications system. It is a figure which shows the structure of the data frame which allocates a HARQ burst in a prior art. FIG. 10 is a diagram for explaining an HARQ signal area allocation method in a HARQ MAP message in the prior art. It is a figure for demonstrating the encoding method according to a layer in a prior art. FIG. 3 is a diagram illustrating a data frame in an OFDMA wireless access system according to a preferred embodiment of the present invention. FIG. 3 is an exemplary diagram illustrating an allocation order of ACK / NACK transfer channels in a preferred embodiment of the present invention. FIG. 3 is a diagram illustrating a scheme for assigning an ACK / NACK transfer channel in an uplink ACK signal area and a downlink ACK signal area according to a preferred embodiment of the present invention. FIG. 6 is a diagram illustrating a scheme for assigning an ACK / NACK transfer channel in an uplink ACK signal area and a downlink ACK signal area according to another preferred embodiment of the present invention. FIG. 6 is a diagram illustrating a scheme for assigning an ACK / NACK transfer channel in an uplink ACK signal area and a downlink ACK signal area according to still another embodiment of the present invention.

Claims (19)

A method for transmitting packet data in a wireless communication system configured to support multiple inputs and outputs, comprising:
The method
Receiving a downlink data frame comprising a plurality of data map information elements and at least one data burst comprising a plurality of layers, each of the plurality of layers being encoded with a corresponding channel encoder, One of the plurality of data map information elements is configured to provide control information associated with each of the plurality of layers, and another one of the plurality of data map information elements is an uplink Configured to provide an acknowledgment channel area, wherein an acknowledgment state of each of the plurality of layer signals is assigned to an associated acknowledgment channel in the uplink data frame;
In the uplink reception confirmation channel, transmitting a plurality of reception confirmation states, each of the plurality of reception confirmation states is whether or not the corresponding layer of the plurality of layers is correctly decoded. Related, including and
Each of the plurality of reception confirmation states is represented by a combination of a plurality of modulation symbol groups ,
Each of the plurality of acknowledgment states is represented by 24 subcarriers, the 24 subcarriers including a combination of 3 modulation symbol groups, and the 3 modulation symbol groups are:

Selected from the group sets G0 to G7 described in .   The control information of each of the plurality of layers includes at least one of a HARQ ID sequence number, a subpacket identifier, a traffic interval, a HARQ channel identifier, a retransmission state, and a value for selecting different redundancy bits during retransmission. The method of claim 1 comprising.   The method of claim 1, wherein the channel encoder comprises a forward error correction encoder.   The method of claim 1, wherein each of the plurality of data map information elements includes a HARQ map information element configured to provide the uplink acknowledgment channel area.   The method of claim 1, wherein half of the subchannels are used for each acknowledgment state.   The method of claim 1, wherein each of the plurality of data map information elements includes a downlink map information element. A method for transmitting packet data in a wireless communication system configured to support multiple inputs and outputs, comprising:
The method
Transmitting a downlink data frame comprising a plurality of data map information elements and at least one data burst comprising a plurality of layers to a receiving device, each of the plurality of layers being encoded by a corresponding channel encoder And wherein one of the plurality of data map information elements is configured to provide control information associated with each of the plurality of layers, and another one of the plurality of data map information elements is Configured to provide an uplink acknowledgment channel area, wherein the acknowledgment status of each of the plurality of layer signals is assigned to an associated acknowledgment channel in the uplink data frame;
Receiving a plurality of acknowledgment states in an uplink acknowledgment channel, wherein each of the plurality of acknowledgment states is a corresponding layer of the plurality of layers accurately decoded by the receiving device; Related to whether or not
Each of the plurality of reception confirmation states is represented by a combination of a plurality of modulation symbol groups ,
Each of the plurality of acknowledgment states is represented by 24 subcarriers, the 24 subcarriers including a combination of 3 modulation symbol groups, and the 3 modulation symbol groups are:

Selected from the group sets G0 to G7 described in .   The control information of each of the plurality of layers includes at least one of a HARQ ID sequence number, a subpacket identifier, a traffic interval, a HARQ channel identifier, a retransmission state, and a value for selecting different redundancy bits during retransmission. The method of claim 7 comprising.   The method of claim 7, wherein each of the plurality of channel encoders includes a forward error correction encoder.   The method of claim 7, wherein the data map information element comprises a HARQ map information element.   The method of claim 7, further comprising retransmitting data associated with the corresponding layer upon receipt of an acknowledgment indicating that the corresponding layer was not correctly decoded by the receiving device.   The method of claim 7, wherein half of the subchannels are used for each acknowledgment state.   The method of claim 7, wherein each of the plurality of data map information elements includes a downlink map information element. A wireless communication device for transmitting packet data,
The apparatus includes a plurality of antennas that achieve space-time transmit diversity, a plurality of channel encoders, and a controller;
Each of the plurality of channel encoders is associated with a corresponding antenna;
The controller is configured to recognize a transmission data frame including a plurality of data map information elements and at least one data burst including a plurality of layers, each of the layers being a corresponding channel encoder. Encoded, one of the plurality of data map information elements includes control information of each of the plurality of layers, and another one of the plurality of data map information elements includes an uplink acknowledgment channel Configured to provide an area, wherein an acknowledgment state of each of the plurality of layer signals is assigned to an associated acknowledgment channel in the uplink data frame, and the controller further includes a plurality of acknowledgment states It is configured to recognize an uplink reception confirmation channel, and each of the plurality of reception confirmation states includes the plurality of reception confirmation states. The corresponding layer is the receiving device of the ear related to whether it is correctly received, each of the plurality of acknowledgment status is represented by a combination of a plurality of modulation symbol groups,
Each of the plurality of acknowledgment states is represented by 24 subcarriers, the 24 subcarriers including a combination of 3 modulation symbol groups, and the 3 modulation symbol groups are:

The apparatus is selected from the group sets G0 to G7 described in the above .   The control information of each of the plurality of layers includes at least one of a HARQ ID sequence number, a subpacket identifier, a traffic interval, a HARQ channel identifier, a retransmission state, and a value for selecting different redundancy bits during retransmission. 15. The apparatus of claim 14, comprising.   The apparatus of claim 14, wherein the channel encoder comprises a forward error correction encoder.   The apparatus of claim 14, wherein each of the plurality of data map information elements includes a HARQ map information element.   The apparatus of claim 14, wherein half of the subchannels are used for each acknowledgment state.   The apparatus of claim 14, wherein each of the plurality of data map information elements includes a downlink map information element.

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