JP2010010952A - Radio communication device and radio communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately correct errors, while significantly reducing the processing load that accompanies error correction, in a radio communication system to which automatic retransmission control is applied. <P>SOLUTION: A radio terminal 100 comprises a transmitting/receiving part 120, a decoding part 130, and a response transmitting part 150. The decoding part 130 determines whether an error bit is present in each block comprising a part of a plurality of code bits, constituting a code bit sequence. The response transmitting part 150 requests retransmission of a block determined as an error-bit block from a radio base station. The transmitting/receiving part 120 receives a plurality of times the block determined as an error-bit block from the radio base station. The decoding part 130 determines a correction bit, in the plurality of blocks received by the transmitting/receiving part 120, by a majority vote by using each bit at the same position as that of the error bit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus and a wireless communication method to which automatic retransmission control is applied.

  In a wireless communication system, transmission errors frequently occur compared to a wired communication system. In such a wireless communication system, automatic retransmission control (ARQ) is widely used to ensure communication reliability. Furthermore, in recent years, hybrid automatic retransmission control (HARQ) using both ARQ and forward error correction (FEC) has been put into practical use.

  In HARQ, a wireless communication device on the transmission side (hereinafter referred to as a transmission device) transmits an encoded bit sequence to a wireless communication device on the reception side (hereinafter referred to as a reception device). The receiving device performs error correction decoding of the bit sequence received first from the transmitting device. When an error occurs when the decoded bit sequence is checked by CRC, the transmitter is requested to retransmit the bit sequence.

When retransmission is requested, the transmission apparatus retransmits the transmitted bit sequence to the reception apparatus. The receiving device stores the bit sequence received for the first time. When receiving the retransmitted bit sequence, the receiving device combines the stored bit sequence and the retransmitted bit sequence, and combines the combined bits. Sequence error correction decoding is performed (see Patent Document 1). If an error occurs when the decoded bit sequence is checked by CRC, a retransmission request for the bit sequence is requested to the transmission apparatus.
JP 2008-17487 A ([Summary] etc.)

  However, the above-described HARQ has the following problems. Specifically, the receiving apparatus performs error correction decoding on the entire bit sequence at the first reception of the bit sequence and at the second and subsequent receptions of the bit sequence, so that the processing load associated with error correction increases. There was a problem to do. In particular, when a complicated error correction decoding method such as turbo decoding is employed, the processing load described above increases significantly.

  Therefore, the present invention has been made to solve the above-described problem, and in a wireless communication system to which automatic retransmission control is applied, an error can be appropriately corrected and a processing load associated with error correction is increased. An object of the present invention is to provide a wireless communication apparatus and a wireless communication method that are greatly reduced.

  In order to solve the above-described problems, the present invention has the following features. First, the first feature of the present invention is that a wireless communication device (for example, a wireless base station 200) that receives a bit sequence (encoded bit sequence E1) composed of a plurality of bits (for example, a wireless base station 200). An error determination unit (decoding unit 130) that determines whether or not an error bit is included in each block (blocks B1 to B4) that is a part of the bits constituting the bit sequence, A retransmission request unit (response transmission unit 150) for requesting retransmission of the block determined to include the error bit by the error determination unit to the other wireless communication device; and the error determination unit including the error bit. Based on the reception unit (transmission / reception unit 120) that receives the determined block from the other wireless communication device a plurality of times, and the plurality of blocks received by the reception unit, the error is determined. A determination unit (decoding unit 130) that determines a corrected bit obtained by correcting the bit, and the determination unit is configured by majority using each bit at the same position as the error bit in the plurality of blocks received by the reception unit. The gist is to determine the correction bit.

  According to such a wireless communication apparatus, the determination unit determines a correction bit obtained by correcting the error bit by majority using each bit at the same position as the error bit in the plurality of blocks received by the reception unit. By performing error correction processing in units of blocks, the processing load associated with error correction can be greatly reduced as compared with the conventional method in which error correction of the entire bit sequence is performed during retransmission.

  In addition, since it is rare that an error occurs at the same position at the time of multiple receptions, the correction bit is determined by majority vote, so that the error can be easily and compared with a complicated method such as turbo decoding. Can be corrected appropriately.

  A second feature of the present invention relates to the first feature of the present invention, wherein the bit sequence is generated by convolutional coding using a coding rule according to a predetermined trellis diagram in the other wireless communication device. In summary, the error determination unit determines whether or not the error bit is included for each block, using the bit that violates the coding rule as the error bit.

  A third feature of the present invention relates to the second feature of the present invention, wherein the determining unit determines a correction bit candidate that is a candidate for the correction bit at the same position as the error bit according to the encoding rule. The gist is to determine the correction bit by generating from each bit and determining the correction bit by majority between the generated correction bit candidates.

  A fourth feature of the present invention relates to any one of the first to third features of the present invention, wherein the error determination unit is configured such that the error bit is between the error bit and the correction bit determined by the determination unit. Hamming distance or Euclidean distance is calculated as correction energy, and when the correction energy is larger than a predetermined threshold, the retransmission request unit retransmits the block determined to include the error bit when the correction energy is larger than a predetermined threshold. The gist is to request the wireless communication device again.

  A fifth feature of the present invention is a wireless communication method used in a wireless communication device that receives a bit sequence composed of a plurality of bits from the other wireless communication device, wherein the bit sequence constituting the bit sequence A step of determining whether or not an error bit is included in each block composed of a part (step S120), and retransmitting the block determined to include the error bit in the determination step to the other wireless communication device Requesting (steps S130, S160), receiving the block determined to include the error bit in the determining step from the other wireless communication device a plurality of times (steps S110, S140, S170), Based on the plurality of blocks received in the receiving step, the error bit is Determining correct correction bits (steps S150 and S180), and in the determining step, a majority decision using each bit at the same position as the error bit in the plurality of blocks received in the receiving step. The gist is to determine the correction bit.

  Advantageous Effects of Invention According to the present invention, it is possible to provide a wireless communication apparatus and a wireless communication method capable of appropriately correcting errors and greatly reducing the processing load associated with error correction in a wireless communication system to which automatic retransmission control is applied. .

  Next, an embodiment of the present invention will be described with reference to the drawings. Specifically, (1) an overall schematic configuration of the radio communication system, (2) a detailed configuration of the radio communication system, (3) an example of convolutional encoding and decoding processing, (4) an operation example of the radio communication system, (5) ) Actions and effects, (6) Other embodiments will be described. In the description of the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

(1) Overall Schematic Configuration of Radio Communication System FIG. 1 is an overall schematic configuration diagram of a radio communication system 10 according to the present embodiment.

  As shown in FIG. 1, the radio communication system 10 includes a radio terminal 100 and a radio base station 200.

  The radio terminal 100 is located in the communication area of the radio base station 200 and communicates with the radio base station 200 via a radio line. In this embodiment, downlink communication will be mainly described. That is, in this embodiment, the radio terminal 100 configures a radio communication device that receives an encoded bit sequence including a plurality of encoded bits from the radio base station 200 (another radio communication device).

  The wireless communication system 10 employs ARQ. When the radio terminal 100 normally decodes the bit sequence received from the radio base station 200, the radio terminal 100 transmits an acknowledgment (ACK) indicating successful decoding to the radio base station 200.

  When the radio terminal 100 fails to decode the bit sequence received from the radio base station 200, the radio terminal 100 transmits a negative response (NACK) indicating the decoding failure to the radio base station 200. When receiving a NACK from the radio terminal 100, the radio base station 200 retransmits the transmitted bit sequence to the radio terminal 100.

(2) Detailed Configuration of Radio Communication System Next, a detailed configuration of the radio communication system 10, specifically, (2.1) configuration of a radio base station and (2.2) configuration of a radio terminal will be described.

(2.1) Configuration of Radio Base Station FIG. 2 is a block diagram showing the configuration of the radio base station 200. As illustrated in FIG. 2, the radio base station 200 includes an encoding unit 210, a transmission control unit 220, a storage unit 230, a transmission / reception unit 240, and an antenna 250.

  Encoding section 210 encodes an information bit sequence to be transmitted to radio terminal 100 to generate an encoded bit sequence. Here, the information bit sequence is composed of a plurality of information bits. The coded bit sequence is composed of a plurality of coded bits.

  In the present embodiment, the encoding unit 210 generates an encoded bit sequence from the information bit sequence by convolutional encoding. Specifically, convolutional coding is performed for each several bits of a plurality of information bits according to a coding rule according to a predetermined trellis diagram. Hereinafter, a part of a coded bit sequence generated by one-time convolutional coding is appropriately referred to as a “block”. The block is composed of, for example, 8 to 12 encoded bits.

  The transmission control unit 220 passes the encoded bit sequence generated by the encoding unit 210 to the transmission / reception unit 240. The storage unit 230 stores the encoded bit sequence generated by the encoding unit 210.

  The transmission / reception unit 240 transmits the encoded bit sequence to the wireless terminal 100. Specifically, the transmission / reception unit 240 generates a radio signal by modulating the encoded bit sequence, amplifying and up-converting the modulated encoded bit sequence, and the generated radio signal is transmitted to the radio terminal via the antenna 250. To 100.

  When receiving the ACK or NACK transmitted from the wireless terminal 100, the transmission / reception unit 240 notifies the transmission control unit 220 of the ACK or NACK.

  When NACK is notified, the transmission control unit 220 acquires a block requested to be retransmitted from the encoded bit sequence stored in the storage unit 230 and retransmits the acquired block to the radio terminal 100. On the other hand, when ACK is notified, the transmission control unit 220 discards the encoded bit sequence stored in the storage unit 230.

(2.2) Configuration of Radio Terminal FIG. 3 is a block diagram showing the configuration of the radio terminal 100. As illustrated in FIG. 3, the wireless terminal 100 includes an antenna 110, a transmission / reception unit 120, a decoding unit 130, a storage unit 140, and a response transmission unit 150.

  The transmission / reception unit 120 receives an encoded bit sequence from the radio base station 200. Specifically, a radio signal is received from the radio base station 200 via the antenna 110, and after the received radio signal is amplified and down-converted, the encoded bit sequence is demodulated. The encoded bit sequence obtained in this way is input to the decoding unit 130.

  The decoding unit 130 decodes the encoded bit sequence according to an encoding rule according to a predetermined trellis diagram. In the present embodiment, the decoding unit 130 is assumed to decode the encoded bit sequence by hard decision decoding.

  In the decoding process, the decoding unit 130 determines whether or not each block includes an error bit. For example, when a coded bit that violates the coding rule is detected, it is determined that the block includes an error bit. Thus, the decoding unit 130 constitutes an error determination unit that determines whether or not an error bit is included.

  For blocks that do not include error bits, the decoding unit 130 stores the information bit sequence obtained by decoding in the decoding unit 130. On the other hand, for a block including an error bit, the decoding unit 130 generates a correction bit candidate that is a correction bit candidate obtained by correcting the error bit, and stores the generated correction bit candidate in the decoding unit 130.

  The response transmission unit 150 transmits a NACK requesting retransmission of a block determined to include an error bit to the radio base station 200 using the transmission / reception unit 120. At that time, the response transmission unit 150 includes in the NACK information that can identify a block for which retransmission is requested.

  After transmitting the NACK, the transmission / reception unit 120 receives the block retransmitted from the radio base station 200 at least once and passes each received block to the decoding unit 130. That is, in the present embodiment, the transmission / reception unit 120 constitutes a reception unit that receives a block determined to include an error bit a plurality of times (including the first).

  The decoding unit 130 determines a correction bit by majority using each bit at the same position as the error bit in the plurality of blocks received by the transmission / reception unit 120. Specifically, the decoding unit 130 newly generates correction bit candidates for the retransmitted block, and determines correction bits by majority using the correction bit candidates stored in the storage unit 140.

  Thus, in the present embodiment, the decoding unit 130 functions as a determination unit that determines a corrected bit obtained by correcting an error bit. Note that the decoding unit 130 decodes the correction bits determined by the majority decision into information bits.

(3) Example of Convolutional Encoding and Decoding Process Next, an example of the encoding process executed by the encoding unit 210 and the decoding process executed by the decoding unit 130 will be described using FIG.

  For example, the encoding unit 210 has a configuration as shown in FIG. In the example of FIG. 4A, the encoding unit 210 includes registers 211 and 212 that hold information bits, adders 213 and 214 that add information bits, and an output switch 215 that alternately switches the adders 213 and 214. Including. The output switch 215 outputs a coded bit sequence.

  In the encoding unit 210 in FIG. 4A, 2 encoded bits are generated for 1 information bit (encoding rate 1/2). Specifically, when the information bit sequence as shown in the upper part of FIG. 4B is input to the encoding unit 210, the encoding unit 210 converts the encoded bit sequence as shown in the lower part of FIG. Output. Thus, the encoded bit is determined by the current and past information bits.

  FIG. 4C is a trellis diagram showing the relationship between the information bits, the states of the registers 211 and 212, and the encoded bits. In FIG. 4C, a line connecting nodes (states) indicated by circles is called a branch. Each node has two branches. The upper branch corresponds to the information bit “0”, and the lower branch corresponds to the information bit “1”. A value assigned to each branch corresponds to a coded bit.

  As can be seen from FIG. 4C, the transition from each node (state) to the next node (state) is restricted. Therefore, the decoding unit 130 can detect, as an error bit, a coded bit that violates the state transition (coding rule) of the trellis diagram shown in FIG. 4C in the received coded bit sequence.

  In addition, the decoding unit 130 generates encoded bits suitable for the state transition of the trellis diagram illustrated in FIG. 4C as correction bit candidates, and stores the generated correction bit candidates in the storage unit 140. In the example of the trellis diagram shown in FIG. 4C, two correction bit candidates corresponding to the upper and lower branches connected to a certain node are stored as correction bit candidates.

  Then, the decoding unit 130 determines a larger correction bit candidate as a correction bit by majority decision of correction bit candidates by receiving a plurality of times. In addition, the decoding unit 130 compares the correction bit with the encoded bit and calculates correction energy.

  In the present embodiment, hard decision decoding is adopted, so that the Hamming distance is used as the correction energy. The Hamming distance means the number of different bits in the encoded bit and the correction bit candidate. For example, the Hamming distance between the encoded bit “00” and the correction bit candidate “11” is 2, and the encoded bit “ The Hamming distance between 00 ”and the correction bit candidate“ 01 ”is 1.

  When the correction energy calculated by the decoding unit 130 is larger than a predetermined threshold Th, that is, when the reliability of the correction bit is low, the response transmission unit 150 requests retransmission again, and the majority vote is repeated. Executed.

(4) Operation Example of Radio Communication System Next, an operation example of the radio communication system 10 will be described. Specifically, (4.1) Overall schematic operation, (4.2) First reception operation, and (4.3) Second reception operation will be described.

(4.1) Overall Schematic Operation FIG. 5 is a schematic sequence diagram showing the overall schematic operation of the radio communication system 10.

  In step S110, the radio base station 200 transmits the encoded bit sequence E1 to the radio terminal 100.

  In this operation example, the encoded bit sequence E1 includes four blocks B1 to B4 as shown in FIG. In this operation example, it is assumed that the wireless terminal 100 detects, as an error bit, a coded bit that is contrary to the state transition of the trellis diagram in block B2 (step S120).

  When the error bit is detected, the radio terminal 100 stores the encoded bit suitable for the state transition of the trellis diagram as a correction bit candidate. Here, it is assumed that the correction bit candidate to be stored is “a”.

  In step S130, the radio terminal 100 transmits a NACK requesting retransmission of the block B2 to the radio base station 200.

  In step S140, the radio base station 200 retransmits the block B2 requested to be retransmitted to the radio terminal 100.

  In step S150, the radio terminal 100 receives the block B2, and generates a correction bit candidate based on the state transition of the trellis diagram for the encoded bit at the same position as the error bit at the first reception in the block B2. . Here, it is assumed that the generated correction bit candidate is “b”.

  In this case, the correction bit candidate “a” at the first reception is different from the correction bit candidate “b” at the second reception, and the correction bit cannot be determined by majority decision. NACK requesting retransmission is transmitted again to radio base station 200 (step S160).

  Also, the radio terminal 100 compares the encoded bit at the same position as the error bit and the generated correction bit candidate “b” to calculate the correction energy “x”. Then, the radio terminal 100 stores the generated correction bit candidate “b” and the calculated correction energy “x”.

  When the correction bit candidate at the second reception is “a” as in the first reception, “a” is determined as the correction bit by majority vote.

  In step S170, the radio base station 200 retransmits the block B2 requested to be retransmitted to the radio terminal 100.

  In step S180, the radio terminal 100 receives the block B2, and generates a correction bit candidate based on the state transition of the trellis diagram for the encoded bit at the same position as the error bit at the first reception in the block B2. . Here, it is assumed that the generated correction bit candidate is “b”. Also, the radio terminal 100 compares the encoded bit at the same position as the error bit and the generated correction bit candidate “b” to calculate the correction energy “y”.

  In this case, “b” is corrected by majority decision of the correction bit candidate “a” at the first reception, the correction bit candidate “b” at the second reception, and the correction bit candidate “b” at the third reception. Determined as a bit.

  When “b” is determined as the correction bit, the radio terminal 100 compares the correction energies “x” and “y” calculated for “b” with the threshold Th. If “x” and “y” are equal to or smaller than the threshold Th, the radio terminal 100 determines that the correction of the correction bit “b” is high and determines that the block B2 has been successfully decoded, and sends an ACK to the radio base station 200. Transmit (step S190).

(4.2) First Reception Operation Next, the operation of the wireless terminal 100 at the first reception, that is, the details of step S120 in FIG. 5 will be described using FIG.

  In step S121, the decoding unit 130 of the wireless terminal 100 decodes the blocks B1 to B4 included in the encoded bit sequence E1. At that time, the decoding unit 130 determines whether or not each of the blocks B1 to B4 includes an error bit that violates the state transition of the trellis diagram.

  In step S122, the decoding unit 130 of the wireless terminal 100 determines whether a block including an error bit contrary to the state transition of the trellis diagram has been detected. If a block including an error bit is not detected, the process proceeds to step S123. If a block including an error bit is detected, the process proceeds to step S124.

  In step S123, the response transmission unit 150 of the radio terminal 100 transmits ACK indicating that the encoded bit sequence E1 has been normally received to the radio base station 200.

  In step S <b> 124, the response transmission unit 150 transmits a NACK requesting retransmission of a block including an error bit to the radio base station 200. In addition, the decoding unit 130 stores, as error bit candidates, the encoded bits suitable for the state transition of the trellis diagram in the storage unit 140 for the error bits. Further, the decoding unit 130 calculates correction energy between the error bit and the correction bit candidate, and stores the calculated correction energy in the storage unit 140.

  In the case of the operation example of FIG. 5, block B2 including an error bit is detected in step S122, and response transmission section 150 transmits NACK requesting retransmission of block B2 to radio base station 200 in step S124.

(4.3) Second Reception Operation Next, the operation of the wireless terminal 100 at the second reception, that is, the details of step S150 in FIG. 5 will be described using FIG. However, the operation of wireless terminal 100 at the time of the third reception (step S180 in FIG. 5) is the same as step S150 in FIG.

  In step S151, the decoding unit 130 of the wireless terminal 100 receives the retransmitted block, and in the block, the encoded bit at the same position as the error bit at the first reception is based on the state transition of the trellis diagram. A correction bit candidate is generated.

  In step S152, the decoding unit 130 of the wireless terminal 100 compares the encoded bit at the same position as the error bit with the generated correction bit candidate, and calculates correction energy. Then, the wireless terminal 100 stores the generated correction bit candidate and the calculated correction energy in the storage unit 140.

  In step S153, the decoding unit 130 of the wireless terminal 100 determines whether or not the correction bit candidate generated at the first reception matches the correction bit candidate generated at the second reception. If the correction bit candidate generated at the first reception matches the correction bit candidate generated at the second reception, the process proceeds to step S154. If not, the process proceeds to step S156.

  In step S154, the decoding unit 130 of the wireless terminal 100 determines whether or not each of the correction energy calculated at the first reception and the correction energy calculated at the second reception is equal to or less than the threshold Th. If each of the correction energy calculated at the time of the first reception and the correction energy calculated at the time of the second reception is equal to or less than the threshold value Th, the process proceeds to step S155. If the correction energy exceeds the threshold value Th, the process proceeds to step S156. Proceed to

  In step S155, the response transmission unit 150 of the wireless terminal 100 transmits ACK to the wireless base station 200.

  On the other hand, in step S <b> 156, the response transmission unit 150 transmits NACK requesting retransmission of the block determined to include the error bit to the radio base station 200. Further, the decoding unit 130 stores the correction bit candidate generated in step S151 and the correction energy calculated in step S152 in the storage unit 140.

  5, in step S153, it is determined that the correction bit candidate “a” at the first reception does not match the correction bit candidate “b” at the second reception, and the response transmission unit 150 In step S156, NACK requesting retransmission of block B2 is transmitted to radio base station 200.

(5) Operation / Effect As described above, the decoding unit 130 of the radio terminal 100 determines whether or not an error bit is included in each block composed of a part of a plurality of encoded bits constituting the encoded bit sequence. To do. The response transmission unit 150 requests the radio base station 200 to retransmit the block determined to include the error bit. The transmission / reception unit 120 receives a block determined to include an error bit from the radio base station 200 a plurality of times. Then, the decoding unit 130 determines a correction bit by a majority decision using each bit at the same position as the error bit in the plurality of blocks received by the transmission / reception unit 120.

  In this way, by performing error correction processing by majority voting in units of blocks, the processing load associated with error correction processing is significantly reduced compared to conventional methods that perform error correction of the entire encoded bit sequence during retransmission. be able to. In particular, when the wireless terminal 100 is driven by a battery, the power consumption is reduced by significantly reducing the processing load of the wireless terminal 100, so that the driveable time of the wireless terminal 100 can be extended.

  In addition, since it is rare that an error occurs at the same position at the time of multiple receptions, the correction bit is determined by majority vote, so that the error can be easily and compared with a complicated method such as turbo decoding. Can be corrected appropriately. It is apparent that the accuracy of the correction bit determination process based on the majority decision increases as the number of retransmissions increases.

  Further, in the present embodiment, the encoded bit sequence is generated by convolutional encoding using an encoding rule according to a predetermined trellis diagram in radio base station 200. The decoding unit 130 determines whether or not an error bit is included for each block by using a bit that violates the encoding rule as an error bit. Therefore, it is possible to appropriately detect error bits in units of blocks.

  In the present embodiment, the decoding unit 130 generates a correction bit candidate that is a correction bit candidate from each bit at the same position as the error bit according to a coding rule according to a predetermined trellis diagram, The correction bit is determined by majority vote among the correction bit candidates. For this reason, error bits can be corrected with high accuracy.

  In the present embodiment, the decoding unit 130 calculates the Hamming distance between the error bit and the correction bit as correction energy, and the response transmission unit 150 determines that an error occurs when the correction energy is greater than a predetermined threshold Th. The radio base station 200 is requested again to retransmit the block determined to contain the bit. Therefore, when the reliability of the correction bit is low, the majority decision can be redone, and the error bit can be corrected with higher accuracy.

(6) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above-described embodiment, hard decision decoding is adopted, but soft decision decoding may be adopted. In the case of soft decision decoding, Euclidean distance (likelihood) can be used as correction energy.

  In the above-described embodiment, the downlink communication has mainly been described, but the present invention can also be applied to the uplink communication. In this case, the radio base station 200 configures a radio communication device that receives a bit sequence composed of a plurality of bits from the radio terminal 100 (another radio communication device).

  In the above-described embodiment, the case where the radio terminal 100 receives a coded bit sequence that is a bit sequence that has been convolutionally coded has been described. However, the wireless terminal 100 may receive an information bit sequence that is not a coded bit sequence, but is not limited to receiving a coded bit sequence. Even in such a case, the majority process according to the present invention can be applied.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

1 is an overall schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. It is a block diagram which shows the structure of the wireless base station which concerns on embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless terminal which concerns on embodiment of this invention. It is a figure for demonstrating an example of the encoding process performed by the encoding part which concerns on embodiment of this invention, and the decoding process performed by a decoding part. It is a schematic sequence diagram which shows the whole schematic operation | movement of the radio | wireless communications system which concerns on embodiment of this invention. It is a flowchart which shows the detail of step S120 of FIG. It is a flowchart which shows the detail of step S150 of FIG.

Explanation of symbols

  B1 to B4 ... block, E1 ... coded bit sequence, 10 ... wireless communication system, 100 ... wireless terminal, 110 ... antenna, 120 ... transmission / reception unit, 130 ... decoding unit, 140 ... storage unit, 150 ... response transmission unit, 200 DESCRIPTION OF SYMBOLS ... Wireless base station, 210 ... Coding part, 211, 212 ... Register, 213, 214 ... Adder, 215 ... Output switch, 220 ... Transmission control part, 230 ... Memory | storage part, 240 ... Transmission / reception part, 250 ... Antenna

Claims (5)

A wireless communication device that receives a bit sequence composed of a plurality of bits from another wireless communication device,
An error determination unit that determines whether or not an error bit is included in each block including a part of the bits constituting the bit sequence;
A retransmission request unit that requests retransmission of the block determined to include the error bit by the error determination unit to the other wireless communication device;
A receiving unit that receives the block determined to include the error bit by the error determining unit a plurality of times from the other wireless communication device;
A determination unit that determines a correction bit obtained by correcting the error bit based on a plurality of blocks received by the reception unit;
The wireless communication apparatus, wherein the determination unit determines the correction bit by majority using each bit at the same position as the error bit in the plurality of blocks received by the reception unit. The bit sequence is generated by convolutional encoding using an encoding rule according to a predetermined trellis diagram in the other wireless communication device,
The radio communication apparatus according to claim 1, wherein the error determination unit determines whether or not the error bit is included for each block by using a bit that violates the coding rule as the error bit. The determination unit is
According to the encoding rule, a correction bit candidate that is a candidate for the correction bit is generated from each bit at the same position as the error bit,
The wireless communication apparatus according to claim 2, wherein the correction bit is determined by a majority vote between the plurality of generated correction bit candidates. The error determination unit calculates a Hamming distance or a Euclidean distance between the error bit and the correction bit determined by the determination unit as correction energy,
The retransmission request section requests the other wireless communication apparatus to retransmit the block determined to include the error bit when the correction energy is larger than a predetermined threshold. The wireless communication device according to any one of the above. A wireless communication method used in a wireless communication device that receives a bit sequence composed of a plurality of bits from the other wireless communication device,
Determining whether to include an error bit for each block consisting of a part of the bits constituting the bit sequence;
Requesting the other wireless communication device to retransmit the block determined to include the error bit in the determining step;
Receiving the block determined to include the error bit in the determining step from the other wireless communication device a plurality of times;
Determining correction bits obtained by correcting the error bits based on a plurality of blocks received in the receiving step,
In the determining step, the correction bit is determined by majority using each bit at the same position as the error bit in the plurality of blocks received in the receiving step.

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