KR101443540B1 - Method and Apparatus of Circular Buffer-Based Rate Matching and Burst Multiplexing for Packet Data Transmission in a Communication System - Google Patents

Abstract

A method and apparatus for performing rate matching in a communication system according to an embodiment of the present invention, the method comprising: performing channel coding on each of a plurality of data blocks to be transmitted; Interleaving the plurality of interleaved data blocks, and rate-matching each of the interleaved data blocks using a rotation type buffer, wherein the bits output from the rotation type buffer are a redundancy version (RV) ) And the number of output bits of rate matching for each data block, and the first bit of the output bits is determined based on the redundancy version.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a buffer-based rate matching and burst multiplexing method and apparatus for data transmission,

The present invention relates to a method and apparatus for improving performance degradation when channel-encoded packet data in a mobile communication system such as time division multiple access (TDMA) or code division multiple access (CDMA) is multiplexed and transmitted in several bursts.

Factors that deteriorate the quality of high-speed and high-quality data services in wireless communications are largely due to the wireless communication channel environment. In addition to white noise, the wireless communication channel has a frequent channel environment due to a change in signal power due to fading, shadowing, a Doppler effect caused by movement of a terminal and a frequent change in speed, and interference due to other users and multipath signals. . Therefore, in order to provide the high-speed wireless data packet service, other advanced technologies that can enhance the adaptability to the channel change are required in addition to the technologies provided in the existing second generation or third generation mobile communication systems. In a mobile communication system, a channel coding technique is used as an effort to reduce the influence of signal distortion or noise in high-speed data transmission / reception. For example, Convolutional Codes or Turbo Codes are widely used as channel encoders in the second and third generation mobile communication systems. 3GPP (3 ^rd Generation Partnership Project) which is a standard for high-speed data packet transmission system, Adaptive Modulation and Coding Schemes (AMCS) and Hybrid Automatic Repeat Request (HARQ) ) Are commonly referred to.

In the most widely used 3GPP GERAN (Global System for Mobile Telecommunication (GSM) / Enhanced Data Rates for GSM Evolution (EDGE) Radio Access Network (EDGE) system), a link quality control technique is used. Link adaptation (hereinafter referred to as LA) technique and incremental redundancy (hereinafter referred to as IR) technique are employed as a link quality control technique.

The LA technique is a method of changing modulation and coding schemes (hereinafter referred to as MCS) according to the change of the channel environment. The channel environment of the downlink is known by measuring the signal-to-noise ratio at the UE and transmitting the information to the BS through the uplink. The BS estimates the environment of the downlink channel based on the information, Specify the appropriate MCS based on the value. Therefore, in a system employing the LA technique, when a normal channel environment such as a terminal near a base station has a normal channel environment, a high-order modulation scheme and an MCS employing a high coding rate are used. In a case where the channel environment deteriorates, And transmits the packet data using each of the MCSs to which the rate is applied.

The IR scheme is a means of the hybrid ARQ scheme. When an error occurs in an initially transmitted data packet, retransmission of a packet is required to compensate for the error packet. The link quality control technique used at this time is the IR technique. IR technique is technically divided into a full incremental redundancy (FIR) technique and a partial incremental redundancy (PIR) technique. The FIR technique improves the performance of the decoder in the receiving end by transmitting only the bits of the residual bits generated by the channel encoder instead of the same packet. That is, the decoder utilizes new redundant bits as well as information received at the time of initial transmission at the time of decoding, resulting in a decrease in the coding rate, thereby enhancing the performance of the decoder.

Recently, 3GPP GERAN has been advancing the GERAN evolution standard for high speed data transmission, system performance improvement and service quality improvement. In the downlink and uplink packet transmission schemes, a high-order modulation scheme (16QAM, 32QAM), a turbo code and an increased symbol rate are newly introduced for high-speed data transmission. In the conventional EDGE, up to two RLC data blocks are transmitted per radio block. In the advanced GERAN, up to four RLC data blocks are allowed to be transmitted per radio block. Therefore, the channel coding chain structure for efficient data transmission to the MCS scheme combining the newly designed higher order modulation scheme and the turbo code (or convolutional code) should be determined. The newly proposed channel coding scheme should maintain the same connection scheme as that of the existing EDGE packet transmission scheme and ensure backward compatibility such as support of link quality control function.

Meanwhile, Circular Buffer Rate Matching (CBRM) technique, which is one of the conventional rate matching techniques, is a simple method that can support LA and IR techniques in combination with a newly added MCS level in a GERAN evolutionary system It is efficient technology. In addition, the rotational buffer rate matching technique can be used without an external channel interleaver, thereby reducing the complexity of the system implementation.

1 and 2 are block diagrams of a conventional CBRM scheme for a mother code rate of 1/3 of an encoder.

FIG. 1 shows an example of a CBRM scheme for a case where an unstructured convolutional code is used.

As shown in FIG. 1, the bits P ₀ , P ₁ , and P ₂ (101 to 103) encoded by the convolutional encoder 100 are passed through independent sub-block interleavers 111 to 113, respectively. However, in the case of using non-systematic convolutional codes, information bits or systematic bits can not be distinguished from parity bits. Therefore, interleaved bits 121 123 are interlaced with each other at intervals of one bit, and are stored in a circular buffer (CB) 130.

FIG. 2 shows an example of a CBRM technique for the case of using a turbo code.

Referring to FIG. 2, as in the case of FIG. 1, the information bits and the residue bits 201 to 203 encoded by the turbo encoder 200 are interleaved in independent sub-block interleavers 211 to 213, respectively. The interleaved bits 221 to 223 are separated into information bits and redundant bits and stored in the CB 230, respectively. At this time, the redundant bits are arranged so as to be intertwined with each other by one bit as shown in FIG. 1 and stored in the CB 230.

The MCS used in GERAN requires only two to three rate matching patterns according to the coding rate in order to support the IR technique. That is, two rate matching patterns (or RV) are required when the coding rate is (r? 2/3) and three rate matching patterns (RV) when the coding rate is r> 2/3. Therefore, in applying the CBRM technique to GERAN, the RV is determined to sequentially select transmission data from the conventional CB. In this case, the performance degradation of the IR technique due to the partial overlap between the data transmitted during retransmission and the data transmitted during the retransmission .

In GERAN, for example, in the case of GERAN evolution, at least one to at most four RLC data blocks are transmitted in one radio block. Each RLC data block undergoes an independent channel coding process and puncturing, performs channel inversion on all RLC data to be transmitted, and then distributes and transmits information to four bursts. The GERAN system is a structure in which eight timeslots constitute one Time Division Multiple Access (TDMA) frame, and one burst is carried in one time slot. Therefore, in the case of a terminal that does not support multislot capability, it is dispersed in four TDMA frames and transmitted. Therefore, when the CBRM scheme is employed in the GERAN system, as shown in FIGS. 1 and 2, the CBRM apparatus includes a sub-block interleaver. Therefore, independently channel-coded data is dispersed into four bursts without going through an external channel interleaver Lt; / RTI > Therefore, when multiple RLC data blocks are sequentially mapped to four bursts without being subjected to an external channel interleaving process, performance may be degraded due to a burst error.

In particular, when turbo codes are used, as shown in FIG. 2, data is divided into information bits and redundant bits in order to maximize the coding gain. Therefore, as described above, when a plurality of RLC data blocks are sequentially mapped to four bursts and transmitted without going through the external channel interleaving process, the performance of the cell protection due to a burst error may be deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for applying CBRM to a channel coding chain for efficient data transmission in a GERAN system.

Another object of the present invention is to provide a method for determining a rate matching pattern for each MCS used in GERAN when CBRM is applied.

Another object of the present invention is to provide a burst multiplexing method and apparatus for reducing a cluster error when mapping a plurality of RLC data blocks to a plurality of bursts through a channel coding process.

A transmission method for performing rate matching in a communication system according to an exemplary embodiment of the present invention includes performing channel coding on each of a plurality of data blocks to be transmitted, interleaving the channel- And rate-matching the plurality of interleaved data blocks using a rotatable buffer, wherein the bits output from the rotatable buffer include a redundancy version (RV) and a rate matching output for each data block Wherein the first bit of the output bits is determined based on the redundancy version.
In addition, according to an embodiment of the present invention, a transmitter for performing rate matching in a communication system includes a channel encoder for performing channel encoding on each of a plurality of data blocks to be transmitted, and a transmitter for interleaving the channel- And a rate matching unit for rate matching the plurality of interleaved data blocks using a rotatable buffer. The bits output from the rotatable buffer are divided into a redundancy version (RV) and a rate of each data block Is determined based on the number of output bits of the matching, and the first bit of the output bits is determined based on the redundancy version.
According to another aspect of the present invention, there is provided a receiving method for recovering rate-matched data bits in a communication system, the method comprising: receiving the rate-matched multiple data blocks; And performing channel decoding on each of the plurality of reconstructed data blocks, wherein the bits input from the rotation type buffer include a redundancy version : RV) and the number of output bits of rate matching for each data block, and the first bit of the input bits is determined based on the redundancy version.
According to another aspect of the present invention, there is provided a receiving apparatus for recovering rate-matched data bits in a communication system, the apparatus comprising: a receiving unit for receiving the rate-matched data blocks, And a channel decoder for performing channel decoding on each of the plurality of recovered data blocks, wherein the bits input from the rotatable buffer are a redundancy version, Version: RV) and the number of output bits of rate matching for each data block, and the first bit of the input bits is determined based on the redundancy version.

Effects obtained by representative ones of the inventions disclosed below will be briefly described as follows.

The present invention can reduce the performance degradation of turbo codes in IR retransmission by efficiently determining two or three RVs according to the data code rate in a wireless communication system using CBRM.

Also, in a wireless communication system using CBRM, in particular, when a plurality of RLC data blocks are transmitted in a radio block, the coded data of n RLC data blocks are mapped into bursts of m bits in units of bits without using an external channel interleaver, By performing multiplexing, it is possible to prevent cluster errors that may occur in the existing sequential mapping.

Also, in the case of matching symbols in consideration of the importance of coded bits, the channel coding gain can be improved through symbol mapping after independent burst multiplexing.

2/3에 대한 RV2 결정방법을 나타낸 도면,
도 5는 본 발명의 실시예에 따라 CBRM에서 데이터 부호율 r>2/3에 대한 RV3 결정방법을 나타낸 도면,
도 6은 본 발명의 실시예에 따라 전송 데이터를 4개의 버스트로 다중화하는 방법을 도시한 도면,
도 7은 본 발명의 실시예에 따라 전송 데이터를 비트의 중요도를 고려하여 4개의 버스트로 다중화하는 방법을 도시한 도면,
도 8은 본 발명의 실시예에 따른 RLC 데이터 블럭 복호를 위한 수신부의 구조를 나타내는 도면,
도 9는 본 발명의 실시예에 따른 송수신부의 신호 흐름도,
도 10은 본 발명의 실시예에 따른 수신부의 신호 흐름도.FIG. 1 is a block diagram of a conventional buffer rate matching apparatus for a non-systematic convolutional encoder,
FIG. 2 is a diagram illustrating a structure of a rotation type buffer rate matching apparatus for a general turbo encoder;
3 illustrates a structure of a transmitter for RLC data block transmission in a physical layer of a GERAN system according to an embodiment of the present invention;
Figure 4 is a block diagram of an embodiment of the present invention in which the data code rate r

2 < / RTI >
5 is a diagram illustrating a method of determining RV3 for a data code rate r > 2/3 in CBRM according to an embodiment of the present invention;
FIG. 6 is a diagram illustrating a method of multiplexing transmission data into four bursts according to an embodiment of the present invention;
FIG. 7 is a diagram illustrating a method of multiplexing transmission data in four bursts in consideration of importance of bits according to an embodiment of the present invention; FIG.
8 is a diagram illustrating a structure of a receiver for RLC data block decoding according to an embodiment of the present invention;
9 is a signal flow diagram of a transmitting / receiving unit according to an embodiment of the present invention,
10 is a signal flow diagram of a receiver according to an embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an operation principle of an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

Before describing the present invention, the general CBRM process will be described first.

The general CBRM process is performed in four steps as described below.

Step 1 : Bit Separation

The sub-bit streams encoded from the channel encoder are divided into a plurality of sub-blocks, respectively, according to the mother code rate. For example, FIGS. 1 and 2 show an example of a case where the mother code rate is 1/3, and the output of the channel encoder is divided into three sub-blocks. More specifically, FIG. 1 illustrates a case where Nsystemic Convolutional Codes are used. The output C of the encoder 100 is divided into three redundant bit sub-blocks P ₀ 101, P ₁ 102 and P ₂ 103 2 shows the case of using the turbo protection, the output C of the encoder 200 is divided into one information bit sub-block S 201 and two redundant bit sub-blocks P ₁ 202 and P ₂ 203 Separated.

Step 2 : Sub-block interleaving

The plurality of subblocks are independently subjected to subblock interleaving. Various techniques can be applied by the interleaving method. As an example, a BRO (Bit-Reversed Order) interleaver may be used.

Step 3 : Bit Grouping

The interleaved sub-blocks are stored in a rotatable buffer (CB). 1, three interleaved redundant bit subblocks P ' ₀ 121, P' ₁ 122 and P ' ₂ 123 are interlaced bit by bit, . That is, the bit sequence stored in the CB (130) is _{CB = [P '0 (0} ), P' 1 (0), P '2 (0), P' 0 (1), P '1 (1), P ' ₂ (1), ... ] = [CB (0), CB (1), ... , CB (3N-1)]. 2, unlike the convolutional encoder, an interleaved information bit sub-block S '221 and two interleaved sub-blocks P' ₁ 222 and P ' ₂ 223 are separated CB 230 as shown in FIG. That is, CB = [S '(0), S' (1), ... , P ' ₀ (0), P' ₁ (0), P ' ₀ (1), P' ₁ (1), ... ] to be.

Step 4 ; Select transmission bit (or RV decision)

The fourth step is a process of selecting data to be transmitted from the CB. If the number of bits to transmit is Nc, Nc bits are selected from the beginning of the buffer for the first transmission. In the case of retransmission for the IR scheme, Nc bits are selected and transmitted from the next bit of the last bit used in the first transmission. In this order, Nc bits for the next retransmission are selected. When selecting the bit to be retransmitted at one time, if the last index of the CB is reached, it returns to the beginning of the CB and continues to select the bits to be transmitted.

Next, a structure of a transmitter according to an embodiment of the present invention for applying CBRM to a GERAN system will be described.

3 shows a transmitter structure according to an embodiment of the present invention for applying a CBRM to a GERAN system.

FIG. 3 shows a structure in which channel encoding is performed on n RLC data blocks per radio block, and information is distributed to m bursts through a series of processes. Indeed, in the GERAN system, four bursts per radio block (i.e., m = 4) are used. FIG. 3 shows a structure of a rate matching apparatus for transmitting n RLC data blocks per radio block, but it can also be applied to transmission of one RLC data block (i.e., n = 1) per radio block It is easy to see.

Referring to FIG. 3, the structure of the transmission unit will be described in detail. The n RLC data blocks are allocated CRC bits independently from Cyclic Redundancy Check Attachments (Cyclic Redundancy Check Attachments) 301 to 303, 313). The outputs of the channel encoders 311 to 313 for each RLC data block are denoted as C ₁ , C ₂ , ... , And C _n . The encoded data block _{C i (i = 1,2, ...} , n) are sent respectively by the CBRM device (321 to 323). The CBRM devices 321 to 323 perform a series of rate matching processes as described above, and then determine an RV for selecting a bitstream to be transmitted from the CB. In FIG. 3, a bitstream selected from CB according to the determined RV is _denoted as CB _i (i = 1, 2, ..., n). The data blocks CB _i (i = 1, 2, ..., n) are sent to a burst multiplexer 330. In the burst multiplexer 330, the data block CB = {CB ₁ , CB ₂ , ... , CB _n } to m bursts (B ₀ to B _m ). When considering the priority of a transmission bit in performing burst multiplexing, a transmission bit is divided into a bit having a higher priority and a bit having a low priority, (E.g., 8PSK, 16/32/64 / ... QAM, etc.). However, if the burst mapping is performed without considering the bit importance, the bit relocation step can be omitted. Next, the data transmitted to the burst mapper 350 are respectively mapped to corresponding bursts (Burst # 1 to Burst # m). In the case of the GSM / EDGE system, as shown in FIG. 3, the burst format is a midamble of a burst, and a training sequence code (hereinafter referred to as TSC) 371 is located. The bits to be transmitted are mapped together with header information (information such as Heather Information - Header, USF, and Stealing Flag). Each burst is mapped to a physical channel and transmitted via a modulator 360. In the case of the GERAN system, each burst is allocated and transmitted in a timeslot within the TDMA frame. FIG. 3 shows a case where the user is allocated the fifth time slot (t = 4) among the TDMA frames constituted by eight time slots (t = 0, 1, 2, ..., 7).

Next, an RV determination method according to an embodiment of the present invention will be described.

In applying CBRM, 8 RVs are defined in CB in 3GPP Long Term Evolution (LTE) system. However, as mentioned above, the MCS used in the GERAN system uses a convolutional code or turbo code having a mother code rate (Rc) of 1/3. To support the IR scheme, two or three RVs Only.

Before explaining the concrete RV determination method, the parameters used in the following description are defined as follows.

- Ni: number of information bits contained in all RLC data blocks transmitted per radio block

- Na: the total number of bits, which is the sum of the number of bits generated after channel encoding and the number of tail bits of the channel encoder due to CRC addition

- Nt: the number of all bits output from the channel encoder, i.e. Nt = 3Ni + Na

- N: N = Nt / 3

- Nc: total number of bits transmitted through 4 bursts

- r: coding rate of transmission data, r = Ni / Nc

When n RLC data blocks are transmitted, Ni and Nc are defined as follows.

- Ni = n * Ni1, where n is the number of RLC data blocks transmitted and Ni1 is the number of information bits contained in one RLC data block

- Nc = n * Nc1, where Nc1 is the number of bits to select from one CB

If the coding rate is r ≤ 2/3 (Ni / Nc), two RVs shall be defined. If the coding rate is r> 2/3, three RVs shall be defined. Therefore, when applying the CBRM to the GERAN system, when determining the RV for selecting the bitstream from the conventional CB, the data to be sequentially transmitted is selected from the first index of the CB, that is, CB (0) The bitstream selected by the RV for retransmission may be composed of information that is substantially duplicated with the already transmitted bitstream, which may lead to performance degradation of the IR scheme. For example, if the coding rate is 0.5 or less, the bit stream selected by the RV2 for the second transmission overlaps most of the bitstream selected by the RV1 for the first transmission. Also, when the coding rate is r = 2/3, the bitstream selected by RV3 for the third transmission overlaps with the bitstream of RV1, which may cause performance degradation. Therefore, the present invention proposes a method of determining the RV according to the data code rate as follows. FIGS. 4 and 5 illustrate a method of determining the RV according to an embodiment of the present invention by dividing the data code rate into two cases.

FIG. 4 shows a case where the coding rate is r? 2/3. In this case, two RVs, that is, RV1 and RV2 are required. The bit stream of RV1 is selected in accordance with the conventional method. As shown in FIG. 4, the bit stream of RV1 is expressed by Equation (1).

That is, the bit stream 401 of RV1 is composed of Nc bits starting from the first bit CB (0) of CB. The bitstream of RV2 is conventionally selected (402) starting from CB (Nc) bits to CB (3N-1) bits in selecting Nc bits and the remaining bits starting from CB (0) (403). ≪ / RTI > That is, the bit stream of RV2 is expressed by Equation 2 below.

When the bits to be included in the bitstream of RV2 are selected in the conventional manner, the bitstream 403 corresponding to RV2-part2 in Equation (2) exactly overlaps with the beginning of the bitstream 401 of RV1. That is, the bitstream of RV2 partially overlaps with the bitstream of RV1. Accordingly, in the present invention, as shown in FIG. 4, in selecting the bits to be included in the bitstream of RV2-part2, a first method of selecting uniformly distributed bits as possible from the bitstream of RV1, And a second method of selecting bits by treating the information bits as bits of high importance.

First Method: A bitstream 411 of RV2-part2 is a bitstream of RV1 [CB (0), CB (1), ...). , And CB (Nc-1), respectively, by performing uniform puncturing as uniform as possible. This method can be expected to perform well in decoding when retransmitting without considering the importance of information bits and redundant bits like unstructured convolutional codes.

The second method: Bitstream 421 of RV2-part2 contains [CB (0), CB (1), ... , And CB (N-1), respectively, by performing uniform puncturing as uniform as possible. [CB (0), CB (1), ... , CB (N-1)] corresponds to the information bits when channel-coded by the turbo encoder, the information bits can be retransmitted as much as possible as compared with the redundant bits. Therefore, good performance can be expected in the turbo decoding process.

Next, FIG. 5 shows a case where the code rate is r > 2/3. In this case, three RVs, i.e., RV1, RV2 and RV3 are required. The bits to be included in the bitstream of RV1 and the bits to be included in the bitstream of RV2 are selected according to a conventional method. That is, as shown in FIG. 5, the bit stream 501 of RV1 and the bit stream 502 of RV2 are expressed by Equation (3).

In the conventional case, the bit stream of RV3 is selected from CB (2Nc) bits to CB (3N-1) bits in selecting Nc bits (503) (504). That is, the bit stream of RV3 is expressed by Equation (4).

When the bits to be included in the bitstream of RV3 are selected in the conventional manner, the bitstream 504 corresponding to RV3-part2 in Equation 4 exactly overlaps with the beginning of the bitstream 501 of RV1. That is, the bit stream of RV3 partially overlaps with the bit stream of RV1. Therefore, in the present invention, as shown in FIG. 5, in selecting the bits to be included in the bitstream of RV3-part2, the first, second and third methods for selecting from the bitstream of RV1 and the bitstream of RV2, And a fourth method in which the bit is treated as a high bit.

First method: The bits to be included in the bitstream 511 of RV3-part2 are selected by 50% from the beginning of the bitstream 501 of RV1 and the beginning of the bitstream 502 of RV2, respectively.

Second method: The bits to be included in the bitstream 521 of RV3-part2 are selected by 50% from the beginning of the bitstream 501 of RV1 and the beginning of the bitstream 502 of RV2, respectively.

Third method: The bits to be included in the bit stream 531 of RV3-part2 are divided into a bit stream 501 of RV1 and a bit stream 502 [CB (0), CB (1), ..., , CB (2Nc-1)], as shown in FIG. This method can expect good performance in the decoding process when retransmitting without considering the importance of information bits and redundant bits like unstructured convolutional codes.

Fourth method: This method is the same as the second method in the case of r? 2/3, The bit stream 540 of RV3-part2 contains [CB (0), CB (1), ... , And CB (N-1), respectively, by performing uniform puncturing as uniform as possible. [CB (0), CB (1), ... , CB (N-1)] corresponds to the information bits when channel-coded by the turbo encoder, the information bits can be retransmitted as much as possible as compared with the redundant bits. Therefore, good performance can be expected in the turbo decoding process.

The RV determination method described above is applied to each RLC data block even when transmitting n RLC data blocks. For example, it constitutes a total transfer data from RV to the selected _{CB i (i = 1, 2} , ..., n) for each of the coded RLC block. That is, the following equation (5) is obtained.

Here, CB _i Includes Nc / n bits as a bit stream of RV selected from the i-th RLC data block.

Next, a burst multiplexing method according to an embodiment of the present invention will be described.

The bitstream of the RV selected in the above-described manner is multiplexed into m bursts in the burst multiplexer. In the case of the GERAN system, four bursts are multiplexed. When using the CBRM scheme, since the CBRM apparatus includes a sub-block interleaver, an external channel interleaver may not be used in order to avoid complexity. Therefore, in the multiplexing process, bit multiplexing must be performed so that the bitstream of the RV transmitted from each RLC data block is dispersed as much as possible into each burst even if an external channel interleaver is not used. Hereinafter, a method of bit multiplexing according to an embodiment of the present invention will be described in two cases.

First, a bit multiplexing method in a case where bit importance in a symbol is not considered will be described.

In this case, the bitstream of the RV to be transmitted is transmitted without considering the importance of each bit included in the bitstream, and the bits encoded with the RLC data block must be bit-multiplexed so as to be well dispersed into m bursts. The output sequence of the CB generated from the encoded jth RLC data block, that is, CB _j in Equation (5), can be expressed by Equation (6).

Where M is a multiple of m in number of bits and m = 4 for a GERAN system. The bit c _{j , i} represents the i-th bit of the j-th CB _j , CB _j (i).

The bit stream B _L allocated to the Lth burst (L = 0, 1, 2, 3) in the GERAN system can be expressed by Equation (7).

Where n is the number of RLC data blocks. The rule for applying m burst-to-burst multiplexing using Equations (6) and (7) is shown in Equation (8).

Here, b _{L , i} corresponds to the i-th bit of the Lth burst. After performing bit multiplexing on four bursts (m = 4, L = 0, 1, 2, 3), the data bits allocated to each burst can be expressed by Equation (9).

Although the above-described technique has been described as an example in which a plurality of RLC data blocks are transmitted, it is natural that the present invention can be applied to a case where one RLC is transmitted, that is, n = 1.

FIG. 6 is a diagram illustrating bit multiplexing using Equation 8 according to an embodiment of the present invention. Referring to FIG.

Next, a bit multiplexing method when bit importance in a symbol is considered will be described.

In this case, the bitstream of the RV to be transmitted is transmitted in consideration of the importance of each bit included in the bitstream, and the bits encoded with the RLC data block must be bit-multiplexed so as to be well dispersed into m bursts. The output sequence to the CB generated from the encoded jth RLC data block, i.e. CB _j in Equation (5), can be expressed as Equation (10).

Here, the bits c _{j , i} (i = 0,1, ..., M1-1) are high priority bits and d _{j , i} (i = Which means high priority bits. M1 and M2 denote the number of bits of high importance and the number of bits of low importance, respectively, and M1 and M2 are multiples of m. The method of dividing the data bits into c _{j , i} and d _{j , i} in consideration of the importance can be applied to the method described in Korean Patent Application No. 10-2007-0059163 filed by the present applicant.

The bit stream B _L allocated to the Lth burst (L = 0, 1, 2, 3) in the GERAN system can be expressed by the following equation (11).

Where n is the number of RLC data blocks. The rule for applying m burst-to-burst multiplexing using Equations (6) and (7) is as follows.

Here, b _{L , i} corresponds to the i-th bit of the Lth burst. The bits of high importance and the bits of low importance are separated from each other for four bursts (m = 4, L = 0, 1, 2, 3) and bit multiplexing is performed. As shown in FIG.

Although the above-described technique has been described as an example in which a plurality of RLC data blocks are transmitted, it is natural that the present invention can be applied to a case where one RLC is transmitted, that is, n = 1.

FIG. 7 is a diagram illustrating bit-multiplexing using Equation (12) according to an embodiment of the present invention.

In the case of a data bit subjected to burst multiplexing, in particular, a bit in which bit multiplexing is performed in consideration of bit importance, a symbol mapping applicable to a higher order modulation scheme such as 8PSK and 16/32/64-QAM can be applied. Such a symbol mapping technique can be applied to the method described in Application No. 10-2007-0059165 filed by the present applicant.

Next, the structure of the receiving unit according to the embodiment of the present invention will be described.

8 illustrates a structure of a receiver for RLC data block decoding according to an embodiment of the present invention.

8, the receiving unit receives m burst data (Received Burst # 1 to #m), estimates the channel state from a training sequence code (TSC) known by the receiving unit, and outputs it to an equalizer A demodulator 800, and the like. The burst demapper 810 separates the header information (Header Info.) And the TSC from each burst data passed through the equalizer 800, and then extracts data of each burst. When a bit rearrangement 820 is applied in the transmitter, a reverse operation for bit retransmission is performed on received data of each burst, and then a burst demultiplexer 830 transmits m burst data . The demultiplexed data D ₁ through D _n reconstruct the respective rotatable buffers CB 841 through 843 and then transmit the RLC data block # 1 through the respective channel decoders 851 through 853, To #n.

FIGS. 9 and 10 show a signal flow diagram for the transmitter and receiver described above. 9 and 10 show a case where a retransmission (IR) scheme based on an ACK / NACK (Acknowledgment / Negative Acknowledgment) signal is applied. That is, when the receiving unit fails to decode the RLC data block, it sends a NACK signal to request data retransmission, and the transmitting unit transmits a bitstream of the new RV stored in the CB at the request of the receiving unit. The receiver stores soft information on previously received data and improves the decoding performance by using both the bit stream of the newly transmitted RV and the soft information of the bit stream of the previously transmitted RV for decoding. When the receiving unit successfully decodes the RLC data block, the receiving unit transmits an ACK signal to the transmitting unit so that the transmitting unit can transmit the new RLC data block (s).

Referring to FIG. 9, when a new RLC data block is generated in step 901, the transmitter adds a CRC to an RLC data block in step 902, performs channel encoding in step 903, and then performs a CBRM process in step 904. FIG. In step 905, the RV bitstream is selected according to the embodiment of the present invention described above, and burst multiplexing is performed in step 906. In step 907, it is determined whether to consider bit importance in a symbol in symbol mapping. If bit importance is considered, bit relocation is performed in step 908. Next, in step 909, each bit is mapped to a multiplexed burst and transmitted.

In step 910, the receiver performs a process of processing the data transmitted from the transmitter, and performs channel decoding in step 911. In step 912, it is determined which of the ACK / NACK signals is to be transmitted according to the channel decoding success, and the corresponding signal is transmitted according to the determination result. Upon receiving the ACK signal from the receiver, the transmitter returns to step 901 and transmits new data. If the NACK signal is received, the transmitter returns to step 905 and performs an operation to retransmit the data.

Referring to FIG. 10, the receiver receives burst data in step 1001, and then performs data equalization in step 1002. FIG. In step 1003, the header information and the TSC are separated through burst inverse mapping, and data is extracted from each burst. In the case where the bit relocation is applied in the transmitter, the inverse operation for bit relocation is performed on the received data of each burst in step 1004, and then the burst data is demultiplexed in step 1005. In step 1006, the demultiplexed data is reconstructed into a rotating buffer CB, and then channel decoding is performed in step 1007 to restore the RLC data block. In step 1008, which of the ACK / NACK signals is to be transmitted according to channel decoding success or not is determined. In step 1009, the ACK / NACK signal is transmitted to the transmitter in steps 1009 and 1010, respectively. After transmitting the ACK / NACK signal, it receives new data or receives retransmitted data.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (11)

delete A transmission method for performing rate matching in a communication system,
Performing channel coding on each of a plurality of data blocks to be transmitted;
Interleaving the channel-encoded data blocks; And
And rate matching the plurality of interleaved data blocks using a rotation type buffer,
Wherein bits output from the rotatable buffer are determined based on a redundancy version (RV) and a number of output bits of rate matching for each data block, and the first bit of the output bits is based on the redundancy version The determined transmission method.
3. The method of claim 2,
And adding a CRC (Cyclic Redundancy Check) to each data block before performing the channel coding.
3. The method of claim 2,
When mapping the rate-matched data bits to a physical layer channel in an uplink transmission,
Wherein the mapped data bits are mapped adjacent to both sides with a reference signal in the middle.
A transmission apparatus for performing rate matching in a communication system,
A channel encoder for performing channel encoding on each of a plurality of data blocks to be transmitted;
An interleaver interleaving the channel-encoded data blocks; And
And a rate matching unit for rate matching the plurality of interleaved data blocks using a rotation type buffer,
Wherein bits output from the rotatable buffer are determined based on a redundancy version (RV) and a number of output bits of rate matching for each data block, and the first bit of the output bits is based on the redundancy version The transmitting device is determined.
6. The method of claim 5,
And a CRC adder for adding a cyclic redundancy check (CRC) to each data block before performing the channel encoding.
6. The method of claim 5,
When mapping the rate-matched data bits to a physical layer channel in an uplink transmission,
Wherein the mapped data bits are mapped adjacent to both sides with a reference signal in the middle.
A receiving method for recovering rate-matched data bits in a communication system,
Receiving the rate-matched data blocks and restoring the received plurality of data blocks into a plurality of data blocks before rate matching using a rotating buffer; And
And performing channel decoding on each of the recovered data blocks,
The bits input in the rotatable buffer are determined based on a redundancy version (RV) and the number of output bits of rate matching for each data block, and the first bit of the input bits is based on the redundancy version The receiving method being determined.
9. The method of claim 8,
When mapping the rate-matched data bits to a physical layer channel in an uplink transmission,
Wherein the mapped data bits are mapped adjacent to both sides with a reference signal in the middle.
A receiving apparatus for recovering rate-matched data bits in a communication system,
A decompressor for receiving the rate-matched data blocks and restoring the received plurality of data blocks into a plurality of data blocks before rate matching using a rotation buffer; And
And a channel decoder for performing channel decoding on each of the plurality of reconstructed data blocks,
The bits input in the rotatable buffer are determined based on a redundancy version (RV) and the number of output bits of rate matching for each data block, and the first bit of the input bits is based on the redundancy version The receiving device being determined.
11. The method of claim 10,
When mapping the rate-matched data bits to a physical layer channel in an uplink transmission,
Wherein the mapped data bits are mapped adjacent to both sides with a reference signal in the middle.

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