JP6602955B2 - Wireless communication method and wireless communication system - Google Patents

Description

Import by reference

  This application claims the priority of Japanese Patent Application No. 2006-65939, which was filed on March 29, 2016, and is incorporated herein by reference.

  The present invention relates to a wireless communication method for transmitting and receiving data via a wireless propagation path.

  Hybrid-ARQ (HARQ) is widely known as a background art in this technical field. HARQ is a method in which ARQ and an error correction code are combined, and is a technique for improving error correction capability at the time of retransmission by using a previous transmission result at the time of decoding. For example, Non-Patent Document 1 discloses a HARQ scheme using a turbo code having excellent error correction capability. In the method disclosed in Non-Patent Document 1, the encoded parity sequence is punctured and transmitted, and when an error occurs, the punctured parity sequence is sequentially added and transmitted for each retransmission.

  In addition, a technique called BICM-ID (Bit Interleaved Coded Modulation with Iterative decoding) has been proposed. For example, as described in Patent Document 1 and Non-Patent Document 2, in BICM-ID, excellent characteristics can be obtained by repeating demodulation processing for modulation and decoding processing for encoding. The characteristics of the BICM-ID are determined not by the characteristics of the demodulator and the decoder but by their matching. For this reason, it is possible to analyze a convergence characteristic using EXT (Extrinsic Information Transfer) analysis and design a demodulator and a decoder that realize excellent characteristics (for example, refer to Non-Patent Document 3). In Non-Patent Document 4, encoding is performed with a code based on a repetitive code, which is a simple code, and multi-level modulation using non-Gray mapping and extended mapping is performed to reduce transmission rate loss. Disclosed is a method for providing a BICM-ID with a small processing capacity of the vessel.

JP 2010-124367 A

D. Garg, F. Adachi, "Rate Compatible Punctured Turbo-Coded Hybrid ARQ for OFDM in a Frequency Selective Fading Channel", IEEE VTC 2003 Spring, pp. 2725-2729, April 2003. X. Li and J. A. Ritcey, "Bit-Interleaved Coded Modulation with Iterative Decoding," IEEE Communications Letters, vol. 1, pp. 169171, 1997. S. ten Brink, "Convergence Behavior of Iteratively Decoded Parallel Concatenated Codes," IEEE Transactions on Communications, vol. 49, No. 10, pp. 1727-1737, October 2001. T. Yano and T. Matsumoto, "Arithmetic extended-mapping for BICM-ID with repetition codes," International ITG Workshop on Smart Antennas, WSA 2009, Berlin, Germany, February 2009.

  In the conventional HARQ scheme, error-free communication is achieved by changing the coding rate of the error correction code based on a value corresponding to an effective signal-to-noise power ratio (SNR), the number of errors, and an estimated value of channel capacity. I do. However, when HARQ is applied to the BICM-ID required in the present invention, the performance of the BICM-ID is determined by the convergence characteristics of the demodulator and the decoder. For this reason, even if the SNR and channel capacity are the same, the convergence characteristics of the demodulator differ depending on the propagation path characteristics and the modulation method, and the characteristics of the decoder that matches the convergence characteristics of the demodulator differ. Therefore, in the code configuration determined based on the SNR and the channel capacity, inappropriate redundant bits are used for retransmission, and there may occur a situation where communication is more error-prone when larger than necessary redundant bits.

A typical example of the invention disclosed in the present application is as follows. That is, a wireless communication method for transmitting data from a transmission device to a reception device, wherein the reception device demodulates a radio signal and outputs bit information; a decoder that decodes the bit information; An interleaving processing unit for switching the bit order of bit information, a deinterleaving processing unit for switching the bit order of the bit information, and a first code optimization processing unit for generating redundant bit control information. The demodulator demodulates a radio signal using a priori information and outputs first bit information, and the interleave processing unit replaces the first bit information with an interleaving process that changes the order of bits. Deinterleave processing for returning the order of the received bits to output second bit information, and the decoder decodes the second bit information The third bit information is output, and the deinterleave processing unit performs an interleave process on the third bit information, which is a reverse process of the deinterleave process, generates fourth bit information, and 4 bit information as the prior information is input to the demodulator to perform iterative decoding processing, and the first code optimization processing unit stops increasing the likelihood due to the iterative decoding processing. Redundancy that maximizes the size of external information when the prior information of the decoder is given at the intersection when the likelihood that the decoder outputs relative to the likelihood input to the decoder is increased by retransmission Generating bit control information, notifying the generated control information to the transmission device, and transmitting the additional redundant bits based on the generated control information. And butterflies.

  According to the representative embodiment of the present invention, communication can be performed while suppressing an increase in redundant bits due to retransmission. Problems, configurations, and effects other than those described above will become apparent from the description of the following embodiments.

It is a figure which shows the structure of the radio | wireless communications system of this invention. It is a figure which shows the resending procedure of the resending method of this invention. It is a figure which shows the iterative decoding process part on the receiving side in the Example of this invention. It is a figure which shows the EXIT analysis result at the time of the first transmission. It is a figure which shows the EXIT analysis result after N times transmission. It is a figure which shows an example of a structure of the encoding modulation process part using the resending method of this invention. It is a figure which shows an example of the characteristic of the code | symbol used with the resending method of this invention. It is a figure which shows an example of the encoding process using the resending method of this invention. It is a figure which shows an example of the convergence characteristic of the decoder in the resending method of this invention. It is a figure which shows an example of a structure of the encoding modulation process part using the resending method of this invention. It is a figure which shows an example of the characteristic of the code | symbol used with the resending method of this invention. It is a figure which shows an example of the encoding process using the resending method of this invention. It is a figure which shows an example of the convergence characteristic of the decoder in the resending method of this invention.

<Example 1>
Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to an embodiment of the present invention.

  The wireless communication system of the present embodiment includes an encoder 10, an interleaver 11, a modulator 12, a transmitter having a code optimization processing unit 19 and an antenna 13, and an iterative decoding processing unit 18, a code optimization processing unit 21 and an antenna 22. It is comprised by the receiver which has. The transmitter and the receiver are connected via a radio propagation path 14.

  In the transmitter, the encoder 10 encodes the information bits, the interleaver 11 switches the bit order in the codeword output from the encoder 10, the modulator 12 modulates, and outputs from the antenna 13.

  The iterative decoding processing unit 18 of the receiver includes a demodulator 15, a deinterleaver 16, a decoder 17, and an interleaver 20. In the receiver, a signal is received via the radio propagation path 14, the demodulator 15 demodulates the received signal, a deinterleaver 16 that performs reverse processing of the interleaver 11 returns the bit order, and a decoder 17 decodes the signal. To do. The decoding result is input to the demodulator 15 via the interleaver 20, and the demodulator 15 refers to the decoding result of the decoder 17 and outputs a further highly accurate demodulation result. In the wireless communication system of this embodiment, the transmitter performs encoding and modulation using the encoder 10, the interleaver 11, and the modulator 12, and the receiver uses the demodulator 15, the deinterleaver 16, the decoder 17, and the interleaver. The BICM-ID is configured by performing iterative decryption using 20.

  In the wireless communication system of the present embodiment, the code optimization processing unit 19 of the transmitter has a function of controlling a redundant bit generation method based on likelihood information obtained by iterative decoding processing with BICM-ID. In the receiver, when an error remains as a result of the repetition process of BICM-ID, the external information (Extrinsic Information) output from the demodulator 15 and the prior information (A Priori Information) input to the demodulator 15 are estimated. Control information (redundant bit information or likelihood information) for determining additional redundant bits to be retransmitted from the transmitter is used as the degree information. The receiver feeds back control information (redundant bit information or likelihood information) to the transmitter together with the retransmission request. Based on the control information from the receiver, the transmitter determines additional redundant bits to be retransmitted and controls the encoder 10. Likelihood information used for code optimization is equivalent before and after the interleaver 20 and the deinterleaver 16, and either of them may be used.

  FIG. 2 is a diagram illustrating a retransmission procedure according to the present embodiment.

  When an initial transmission is performed from the transmitter (24) and an error is detected at the receiver, a retransmission request and code optimization information are fed back from the receiver to the transmitter (25). The transmitter generates a code to be used for retransmission based on the fed back code optimization information, adds a redundant bit, and performs the second transmission (26). The receiver repeats the decoding process by combining the received signal at the first transmission stored in the buffer and the redundant bit added for the second time. If an error remains, the receiver again sends it from the receiver to the transmitter. A retransmission request and code optimization information are fed back (27). Thereafter, the retransmission process is repeated until there is no error at the receiver or the upper limit of the number of retransmissions is reached (28), and when the decoding process is completed without error at the receiver, a reception confirmation response is fed back to the transmitter. (29) The communication process is terminated.

  The overhead required for retransmission may be reduced by not explicitly notifying the receiver of the redundant bit configuration designed by the code optimization processing unit 19 of the transmitter. In this case, the decoder 17 uses the algorithm for determining the same redundant bits in the code optimization processing unit 19 of the transmitter and the code optimization processing unit 21 of the receiver, and the decoder 17 performs redundancy from the code optimization processing unit 21 of the receiver. The bit configuration is obtained and the decoding process is performed.

  FIG. 3A is a diagram illustrating the iterative decoding processing unit 18 of the receiver in the present embodiment, FIG. 3B is a diagram illustrating an EXIT analysis result at the first transmission, and FIG. 3C is an EXIT analysis after N transmissions. It is a figure which shows a result.

  As likelihood information exchanged between the demodulator and the decoder using the BICM-ID, a log likelihood ratio (LLR) in bit units is generally used. LLR is a logarithmic expression of the ratio between the probability that the bit b is 0 and the probability that it is 1, and is expressed by Equation (1).

  In Equation (1), P (b = 0) indicates the probability that b is 0, and P (b = 1) indicates the probability that b is 1.

  The convergence characteristic of the BICM-ID iterative decoding process can be analyzed by EXT (Extrinsic Information Transfer) analysis described in Non-Patent Document 3. In the EXIT analysis, the input / output characteristics of the decoder and demodulator are displayed in the form of the mutual information Im of the bit expressed by the equation (2), and the characteristics of both are overlapped and plotted on one chart for repeated decoding. The amount of information obtained by processing can be analyzed.

  The mutual information amount of Equation (2) is the average of the entire codeword of the mutual information amount of bits, and is expressed by a value of 0 to 1, and the closer to 1, the greater the bit likelihood of the entire codeword.

  When the prior information IA and DEC of the demodulator and the external information IE and DEC of the decoder are taken on the horizontal axis, and the external information IE and DEC of the demodulator and the prior information IA and DEC of the decoder are taken on the vertical axis, The mutual information increases along each characteristic. In the EXIT analysis result 30 at the time of the initial transmission shown in FIG. 3B, the increase in the mutual information amount stops at the point where the characteristics of the two intersect, and an error remains in the decoding result. By changing the characteristics of the decoder from the mutual information amount at the intersection so that the value of the external information when the prior information of the coordinates of the intersection is given becomes larger, the intersection becomes closer to 1. That is, by changing the additional information bits due to retransmission and changing the characteristics of the decoder so that the intersection is closer to 1, residual errors in iterative decoding after retransmission can be reduced. By repeating this process, as shown in FIG. 3C, the characteristics of the decoder are changed so that the convergence characteristics of the demodulator and the decoder do not intersect in the EXIT analysis result 31 after N times of transmission, and an error-free result is obtained. Can be obtained.

  FIG. 4 is a diagram illustrating a configuration example using an iterative code as an example of a coded modulation processing unit using the retransmission method of the present embodiment.

  Since the coded modulation processing unit shown in FIG. 4 uses repetitive codes, the encoder 10 is composed of a repetitive encoder 40.

  In an iterative code, the convergence characteristics of the decoder change even when the code has the same coding rate by combining codes having multiple types of orders. Therefore, additional codes are added based on the code optimization information from the receiver. By controlling the code generation, it is possible to realize convergence characteristics of iterative decoding according to propagation path fluctuations.

  FIG. 5 is a diagram illustrating an example of convergence characteristics of the iterative code decoder in the present embodiment.

  FIG. 5 shows a convergence characteristic 50 in the case of using a repetitive code of order 4, 50% each of a repetitive code of order 2 (coding rate 1/2) and a repetitive code of order 6 (coding rate 1/6). A convergence characteristic 51 in the case where a code having a coding rate of 1/4 is combined. The convergence characteristics 50 and 51 have the same coding rate, but have different convergence characteristics, so that iterative decoding with good characteristics can be realized by designing the code according to the characteristics of the demodulator.

  FIG. 6 is a diagram illustrating an example of a retransmission method using the repetition code according to the present embodiment.

  First, the information bits are duplicated, a repetitive code of degree 2 is generated, a code word 60 used for the first transmission is generated, and the initial transmission is performed. When a retransmission request is received from the receiver after the first transmission, some codes are duplicated as additional redundant bits based on the code optimization information fed back, and the duplicated codes are added for the second and subsequent additional redundant bits. Transmit as (61, 62, 63). The receiver stores all codewords from the time of initial transmission until it is confirmed that they can be decoded without error, and repeatedly performs decoding using all the stored codewords. As a result, since the repetition codes having a plurality of types of orders are combined after the Nth transmission, the characteristics of the decoder matched to the characteristics of the demodulator that extracts information from the transmission signal via the propagation path by repeating retransmission Can be realized.

  FIG. 7 is a diagram illustrating an example of the convergence characteristics of the decoder in the retransmission method using the iterative code according to the present embodiment.

  For the sake of explanation, the number of additional redundant bits to be transmitted in one retransmission is set to 1/5 the size of the codeword at the time of initial transmission, and the redundant bits can be arbitrarily controlled with 1/10 the size of the codeword. To do. The code optimization information is an intersection of the EXIT chart, and the redundant bit is selected by selecting a candidate having the maximum size of the external information when the prior information of the decoder at the intersection is given. The size of the external information of the decoder is calculated using Equation (3) of the convergence characteristic of the next decoder.

  In Equation (3), dv is the order of the repetition code, and ai is the ratio of the repetition code.

  As described above, redundant bits are selected by comparing each candidate based on an arbitrary evaluation index, or by determining the order of an iterative code whose ratio is to be increased based on code optimization information. A method of adding bits can be used. Further, as the code optimization information, the convergence characteristic of the demodulator may be estimated, and the code may be designed based on the estimated convergence characteristic.

  In FIG. 7, the repetition code of order 4 is 20% and the repetition code of order 2 is 80% at the first transmission, and the convergence characteristic 71 of the decoder at the first transmission is the convergence characteristic 70 of the demodulator and the horizontal axis. Crossing at a point of 0.12 and a vertical axis of 0.073, an error occurs in the decoding result.

  Based on the coordinates of the intersection, a method for generating additional redundant bits used for the second transmission is controlled to select additional redundant bits. Additional redundant bit options include increasing the ratio of order 6 repetition codes by 1/5, increasing the ratio of order 5 and order 3 repetition codes by 1/10, and increasing the ratio of order 4 repetition codes by 1/5. There are four methods of increasing the ratio of the repetition code of degree 3 by 1/5. When the code is retransmitted in each method, the external information output by the encoder is 0.17, 0.15, 0.14, and 0.14, respectively. For this reason, the method of increasing the ratio of the repetition code of order 6 by 1/5 increases the external information when the prior information of the decoder at the intersection is given. Thereafter, the same procedure is repeated, and the convergence characteristic 74 of the decoder after the fourth transmission intersects with the convergence characteristic 70 of the demodulator near the coordinates (1, 1). In the present embodiment, for the sake of explanation, only the repetition code is used as the code. However, in the case of crossing near the coordinates (1, 1), a method of combining the repetition code and the SPC (Single Parity Check) code, or a modulator A countermeasure method such as a method of inserting an accumulator with a coding rate of 1 and replacing a part of the code word with an accumulator output is known, and an error-free iterative decoding result is obtained by combining these methods. be able to.

  FIG. 8 is a diagram illustrating an example of a configuration of a coded modulation processing unit using a convolutional code according to the present embodiment.

  Since the encoded modulation processing unit shown in FIG. 8 uses a convolutional code, the encoder 10 includes a convolutional encoder 80. In addition, a puncture processing unit 81 that punctures the code is provided between the convolutional encoder 80 and the interleaver 11.

  In the convolutional code, by combining a plurality of codewords having different constraint lengths, the convergence characteristics of the decoder can be changed even with a code having the same coding rate. When the convolutional code is used, the generation of the convolutional code and the puncturing process are controlled based on the code optimization information from the receiver.

  FIG. 9 is a diagram illustrating an example of convergence characteristics of the decoder of the convolutional code according to the present embodiment.

  FIG. 9 shows a convolutional code convergence characteristic 90 with constraint length K = 2 and coding rate 1/2, and a convergence characteristic 91 of a convolutional code decoder with constraint length K = 7 and coding rate 1/2. . Since the convergence characteristics 90 and 91 have the same coding rate but different convergence characteristics, it is possible to realize iterative decoding with good characteristics by designing the code according to the characteristics of the demodulator.

  FIG. 10 is a diagram illustrating an example of a retransmission method using a convolutional code according to the present embodiment.

  First, the information bits are encoded with a convolutional code having a plurality of constraint lengths to generate a code word, and a part of the code words 100 are extracted by puncturing, and the first transmission is performed. If there is a retransmission request from the receiver after the initial transmission, an additional redundant bit is selected from among the punctured codes based on the code optimization information to be fed back, and the additional redundant bits (101 for the second and subsequent times) are selected. , 102). The receiver stores all codewords from the time of initial transmission until it is confirmed that decoding can be performed without error, and repeatedly performs decoding processing using all the stored codewords.

  FIG. 11 is a diagram illustrating an example of convergence characteristics of a decoder in a retransmission method using a convolutional code.

  For the sake of explanation, the number of additional redundant bits to be transmitted in one retransmission is assumed to be 1/8 the size of the codeword at the first transmission, and the redundant bits can be arbitrarily controlled with the size of 1/8 the codeword. To do. Also, a convolutional code with a coding rate of ¼ using a convolutional code with a coding rate of ½ with a constraint length of K = 2 and a constraint length of K = 7 is used.

  In FIG. 11, at the first transmission, a code obtained by combining a code obtained by puncturing 50% of a convolutional code having a constraint length K = 2 and a code obtained by puncturing 50% of a convolutional code having a constraint length K = 7 is used. The convergence characteristic 111 of the decoder at the time intersects with the convergence characteristic 110 of the demodulator at points of the horizontal axis 0.013 and the vertical axis 0.16, and an error occurs in the decoding result.

  Based on the coordinates of the intersection, a method for generating additional redundant bits used for the second transmission is controlled to select additional redundant bits. There are two options for selecting additional redundant bits: a method in which a punctured untransmitted codeword of a convolutional code having a constraint length K = 2 or a constraint length K = 7 is additionally transmitted. When the code is retransmitted in each method, the external information output from the encoder is 0.038 and 0.022, respectively. For this reason, the method of transmitting the puncture bit with the constraint length K = 2 increases the external information when the prior information of the decoder at the intersection is given. Thereafter, the same procedure is repeated, and the output of the demodulator reaches 1 in the convergence characteristic 113 of the decoder after the third transmission. For this reason, an iterative decoding result without error can be obtained.

  As described above, according to the embodiment of the present invention, since the code generation method is controlled according to the convergence characteristics of the demodulator, the BICM-ID whose characteristics cannot be determined only by the signal-to-noise power ratio and the communication capacity is used. Even in the existing systems, communication can be performed while suppressing an increase in redundant bits due to retransmission.

  Further, since the value based on the likelihood information obtained by the iterative decoding process is notified as control information from the receiving apparatus to the transmitting apparatus, the amount of information fed back from the receiving apparatus to the transmitting apparatus can be reduced. In addition, when the code optimization processing unit 21 of the receiving device and the code optimization processing unit 19 of the transmitting device use the same algorithm and do not explicitly notify the receiver of the configuration of redundant bits, they are necessary for retransmission. Unnecessary overhead can be reduced.

  Also, in the case where the code configuration determined based on the likelihood information obtained by the iterative decoding process is notified as control information from the reception device to the transmission device, an algorithm for determining the configuration of redundant bits on the transmission side is provided. This is unnecessary, and the processing amount on the transmission side can be reduced.

  In addition, when the configuration of redundant bits is explicitly notified to the receiver, it is not necessary to have an algorithm for determining the configuration of redundant bits on the receiving side, and the processing amount on the receiving side can be reduced.

The following are typical examples of aspects of the present invention other than those described in the claims.
(1) A wireless communication system for transmitting data from a transmitting device to a receiving device,
The receiving device is:
A demodulator that demodulates a radio signal and outputs bit information;
A decoder for decoding the bit information;
An interleave processing unit for changing the bit order of the bit information;
A deinterleave processing unit for changing the bit order of the bit information;
A first code optimization processing unit for generating redundant bit control information,
The demodulator demodulates the radio signal using prior information and outputs first bit information;
The deinterleaving processing unit performs deinterleaving processing for returning the order of the bits replaced in the interleaving processing for replacing the order of bits to the first bit information, and outputs second bit information,
The decoder decodes the second bit information and outputs third bit information;
The interleave processing unit performs an interleaving process that is a reverse process of the deinterleaving process on the third bit information, generates fourth bit information, and uses the fourth bit information as the prior information. By inputting to the demodulator, iterative decoding is performed,
The first code optimization processing unit is configured such that the likelihood that the decoder outputs becomes larger by retransmission with respect to the likelihood input to the decoder at a point where the increase in likelihood due to the iterative decoding process is stopped. Generating redundant bit control information, notifying the generated control information to the transmission device,
The wireless communication system, wherein the transmission device transmits additional redundant bits based on the generated control information.

(2) The transmission device includes a second code optimization processing unit,
The control information notified from the receiving device to the transmitting device is a value based on likelihood information obtained by the iterative decoding process,
The first code optimization processing unit and the second code optimization processing unit have the same algorithm for determining a code configuration based on the control information. Wireless communication system.

  (3) The control information notified from the receiving device to the transmitting device has a code configuration determined based on likelihood information obtained by the iterative decoding process. Wireless communication system.

(4) The transmission device includes a second code optimization processing unit,
The wireless communication system according to (1), wherein the second code optimization processing unit transmits a configuration of redundant bits transmitted by the transmission device to the reception device.

  The present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the scope of the appended claims. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to those having all the configurations described. A part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Moreover, you may add the structure of another Example to the structure of a certain Example. In addition, for a part of the configuration of each embodiment, another configuration may be added, deleted, or replaced.

  In addition, each of the above-described configurations, functions, processing units, processing means, etc. may be realized in hardware by designing a part or all of them, for example, with an integrated circuit, and the processor realizes each function. It may be realized by software by interpreting and executing the program to be executed.

  Information such as programs, tables, and files for realizing each function can be stored in a storage device such as a memory, a hard disk, and an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, and a DVD.

  Further, the control lines and the information lines are those that are considered necessary for the explanation, and not all the control lines and the information lines that are necessary for the mounting are shown. In practice, it can be considered that almost all the components are connected to each other.

Claims (8)

  A wireless communication method for transmitting data from a transmitting device to a receiving device,
  The receiving device is:
  A demodulator that demodulates a radio signal and outputs bit information;
  A decoder for decoding the bit information;
  An interleave processing unit for changing the bit order of the bit information;
  A deinterleave processing unit for changing the bit order of the bit information;
  A first code optimization processing unit for generating redundant bit control information,
  The method
  The demodulator demodulates the radio signal using prior information and outputs first bit information;
  The interleave processing unit performs deinterleaving processing for returning the order of the bits replaced in the interleaving processing for replacing the order of bits to the first bit information, and outputs second bit information,
  The decoder decodes the second bit information and outputs third bit information;
  The deinterleave processing unit performs an interleave process on the third bit information, which is a reverse process of the deinterleave process, generates fourth bit information, and converts the fourth bit information to the prior information. As an input to the demodulator to perform iterative decoding processing,
  When the first code optimization processing unit stops the increase in likelihood due to the iterative decoding process, the likelihood that the decoder outputs becomes larger than the likelihood input to the decoder due to retransmission. , Generating redundant bit control information that maximizes the size of the external information when the prior information of the decoder at the intersection is given, and notifying the generated control information to the transmission device,
  The wireless communication method, wherein the transmission device transmits an additional redundant bit based on the generated control information.   The wireless communication method according to claim 1,
  The transmission device includes a second code optimization processing unit,
  The control information notified from the receiving device to the transmitting device is a value based on likelihood information obtained by the iterative decoding process,
  The wireless communication method according to claim 1, wherein the first code optimization processing unit and the second code optimization processing unit have the same algorithm for determining a code configuration based on the control information.   The wireless communication method according to claim 1,
  The wireless communication method characterized in that the control information notified from the receiving device to the transmitting device has a code structure determined based on likelihood information obtained by the iterative decoding process.   The wireless communication method according to claim 1,
  The transmission device includes a second code optimization processing unit,
  The second code optimization processing unit transmits a configuration of redundant bits transmitted by the transmission device to the reception device.   A wireless communication system for transmitting data from a transmitting device to a receiving device,
  The receiving device is:
  A demodulator that demodulates a radio signal and outputs bit information;
  A decoder for decoding the bit information;
  An interleave processing unit for changing the bit order of the bit information;
  A deinterleave processing unit for changing the bit order of the bit information;
  A first code optimization processing unit for generating redundant bit control information,
  The demodulator demodulates the radio signal using prior information and outputs first bit information;
  The interleave processing unit performs deinterleaving processing for returning the order of the bits replaced in the interleaving processing for replacing the order of the bits to the first bit information, and outputs second bit information,
  The decoder decodes the second bit information and outputs third bit information;
  The deinterleave processing unit performs interleave processing on the third bit information, which is reverse processing of the deinterleave processing, generates fourth bit information, and converts the fourth bit information to the prior information. As an input to the demodulator, iterative decoding is performed,
  In the first code optimization processing unit, the likelihood that the decoder outputs becomes larger due to retransmission with respect to the likelihood input to the decoder at the point where the increase in likelihood due to the iterative decoding process is stopped. , Generating redundant bit control information that maximizes the size of the external information when the prior information of the decoder at the intersection is given, and notifying the generated control information to the transmitting device,
  The wireless communication system, wherein the transmission device transmits additional redundant bits based on the generated control information.   The wireless communication system according to claim 5,
  The transmission device includes a second code optimization processing unit,
  The control information notified from the receiving device to the transmitting device is a value based on likelihood information obtained by the iterative decoding process,
  The wireless communication system, wherein the first code optimization processing unit and the second code optimization processing unit have the same algorithm for determining a code configuration based on the control information.   The wireless communication system according to claim 5,
  The wireless communication system, wherein the control information notified from the receiving device to the transmitting device has a code configuration determined based on likelihood information obtained by the iterative decoding process.   The wireless communication system according to claim 5,
  The transmission device includes a second code optimization processing unit,
  The wireless communication system, wherein the second code optimization processing unit transmits a configuration of redundant bits transmitted by the transmission device to the reception device.

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