초록 ▼

Intended is to achieve, in a wide range of an SN ratio, throughput on the same order of that attained by a method based on puncturing and improve computational complexity of decoding processing at a high coding rate. In a communication system for transmitting an error correcting code for an error on

Intended is to achieve, in a wide range of an SN ratio, throughput on the same order of that attained by a method based on puncturing and improve computational complexity of decoding processing at a high coding rate. In a communication system for transmitting an error correcting code for an error on a communication path from a transmitter to a receiver, the transmitter divides information bits of a code word to be transmitted into a plurality of blocks based on a request for retransmission of an error correcting code from the receiver, generates an error correcting code by compact-coding of one block among the plurality of blocks and transmits the generated error correcting code.

대표청구항 ▼

1. A communication system using an error correcting code which is directed from a transmitter to a receiver in order to cope with an error, wherein said transmitter comprises a coding unit which in response to a retransmission request when said receiver fails in decoding, transmits a parity bit stri

1. A communication system using an error correcting code which is directed from a transmitter to a receiver in order to cope with an error, wherein said transmitter comprises a coding unit which in response to a retransmission request when said receiver fails in decoding, transmits a parity bit string generated by compact-coding one information block among a group of information blocks obtained by dividing an information bit string of an error correcting code,in the division into the group of said information blocks at the time of a retransmission request, generates a new first information block by collecting a part of information bits of each information block as of the current time point and executes said compact-coding with respect to the first information block, andgenerates a new group of information blocks by an information block formed of a complementary set of each information block as of the current time point and said first information block and said first information block. 2. The communication system according to claim 1, wherein said first information block is generated such that an information block to be newly generated in response to a retransmission request has the same block length. 3. The communication system according to claim 2, wherein as an error correcting code, a low density parity check code is used whose information part has a regular degree distribution. 4. The communication system according to claim 1, wherein said receiver comprises a decoding unit which executes decoding of said information bit received by using a reception value of said information block of information bits, reception values of said error correcting code received so far and an already decoded information bit string, and when failing in decoding the information block of said information bits, transmits a retransmission request to said transmitter. 5. The communication system according to claim 4, wherein said decoding unit of said receiver, when failing in decoding the information block of said information bits, divides said information bits into the information blocks according to division of said information bits into information blocks by said transmitter together with a retransmission request to said transmitter. 6. The communication system according to claim 1, wherein said coding unit comprises an information bit storage unit, andan information block extraction unit for extracting said first information block of information bits from said information bit storage unit. 7. The communication system according to claim 1, wherein said coding unit calculates said error correcting code as of issuance of a retransmission request in advance and storing the code in an error correcting code storage unit, and upon a retransmission request, selects said error correcting code to be transmitted from said error correcting code storage unit. 8. The communication system according to claim 1, wherein said coding unit comprises an intermediate information generation unit for calculating intermediate information as a product of the information block of said information bits and a corresponding error correcting code check matrix component, andan intermediate information storage unit for storing said intermediate information. 9. The communication system according to claim 1, wherein said transmitter executes division of said information bits into information blocks up to the maximum number of times determined in advance, andretransmits an already transmitted information bit or error correcting code in response to a request for retransmission of said error correcting code whose number of times exceeds said maximum number of times. 10. The communication system according to claim 9, wherein said receiver, when receiving said information bit or error correcting code from said transmitter, executes packet composition as processing of averaging a value of said information bit or error correcting code and a previous reception value thereof. 11. A transmitter which uses an error correcting code which is directed to a receiver in order to cope with an error, comprising a coding unit which in response to a retransmission request when said receiver fails in decoding, transmits a parity bit string generated by compact-coding one information block among a group of information blocks obtained by dividing an information bit string of an error correcting code,in the division into the group of said information blocks at the time of a retransmission request, generates a new first information block by collecting a part of information bits of each information block as of the current time point and executes said compact-coding with respect to the first information block, andgenerates a new group of information blocks by an information block formed of a complementary set of each information block as of the current time point and said first information block and said first information block. 12. The transmitter according to claim 11, wherein said first information block is generated such that an information block to be newly generated in response to a retransmission request has the same block length. 13. The transmitter according to claim 12, wherein as an error correcting code, a low density parity check code is used whose information part has a regular degree distribution. 14. The transmitter according to claim 11, wherein said coding unit comprises an information bit storage unit, andan information block extraction unit for extracting said first information block of information bits from said information bit storage unit. 15. The transmitter according to claim 11, wherein said coding unit calculates said parity bit as of issuance of a retransmission request in advance and storing the code in a parity bit storage unit, and upon a retransmission request, selects said error correcting code to be transmitted from said parity bit storage unit. 16. The transmitter according to claim 11, wherein said coding unit comprises an intermediate information generation unit for calculating intermediate information as a product of the information block of said information bits and a corresponding error correcting code check matrix component, andan intermediate information storage unit for storing said intermediate information. 17. The transmitter according to claim 11, which executes division of said information bits into information blocks up to the maximum number of times determined in advance, andretransmits an already transmitted information bit or parity bit in response to a request for retransmission of said error correcting code whose number of times exceeds said maximum number of times. 18. The transmitter according to claim 17, wherein in response to a request for retransmission of said error correcting code whose number of times exceeds said maximum number of times, transmits a block formed by collecting a part of bits of the information blocks of said information bits or a block formed by collecting a part of bits of a block of parity bits already transmitted. 19. A receiver, which, with respect to the transmitter according to claim 18, executes packet composition processing for reception data in response to a request for retransmission of said error correcting code whose number of times exceeds said maximum number of times and sequentially decodes the information blocks of said information bits starting with a first information block of said information bits. 20. The transmitter according to claim 11, which executes division of said information bit string into information blocks up to the maximum number of times of retransmission requests determined in advance,in response to a request for retransmission whose number of times exceeds said maximum number of times, generates a parity bit as an expansion code for a compact code corresponding to said information block and said parity bit already transmitted, andgenerates a block by collecting parity bits generated by an expansion code corresponding to said information block from the plurality of information blocks and transmits the block in response to a retransmission request.