Communications method, communications apparatus and communications system using same communications apparatus

Abstract

A communications method carries out error-correction encoding of data, generation of a suitable packet in accordance with a retransmission request from a receiving side, and transmission of the packet to the receiving side, from a transmission side. In the receiving side, the communications method performs error-correction decoding of the received data, distinguishing an uncorrectable block in accordance with a result of the error-correction decoding, and transmission of a retransmission request packet to the transmitting side. In this way, if a block in the packet is judged as uncorrectable by the receiving side, where one packet is composed of a plurality of correction blocks of error correction codes of a block type, it is possible to retransmit only the block to be retransmitted. Therefore, it is possible to avoid unnecessary use of bands and to attain a low bit rate.

1 . A communications apparatus, which transmits a data packet composed of a plurality of blocks so as to communicate, comprising: 
 a receiver receiving a request for a retransmission of one or more blocks from a receiving end,    a retransmitter being able to retransmit only said one or more requested blocks of all blocks transmitted in a time frame, by adding said one or more requested blocks to one or more data packets to be transmitted next and/or subsequently time frame to said time frame.    
   
   
       2 . A communications apparatus, which receives a data packet composed of a plurality of blocks so as to communicate, comprising: 
 a data receiver receiving said plurality of blocks from a transmitting end,    a decoder decoding said plurality of blocks,    a retransmission request transmitter being able to transmit a request for a retransmission of one or more blocks of all blocks transmitted in a time frame to said transmitting end based on said decoding result,    wherein, said data receiver can receive only said one or more blocks of all blocks transmitted in a time frame with one or more data packets to be transmitted next and/or subsequently time frame to said time frame.