Patent ID: 6603796
Filing Date: 2003-08-05
Classification: H04L

Abstract:
A radio communication system comprising a transmission apparatus and a reception apparatus,said transmission apparatus including: an encoder for encoding an information to be transmitted and adding an error detection code; a storage for storing a signal to be output from said encoder; a transmission channel for transmitting said information which has been encoded by said encoder so as to be transmitted; a first multiplier provided in said transmission channel, for multiplying an output signal from said encoder by a first diffusion code so as to be a transmission signal destined to said reception apparatus; a second multiplier for multiplying a signal received from said reception apparatus, by a second diffusion code; a decoder for decoding the output signal from said second multiplier; and a transmission/reception block for transmitting and receiving a signal to/from said reception apparatus, and said reception apparatus including: a first multiplier for multiplying a reception signal from said transmission apparatus, by the first diffusion code; a decoder for decoding an output signal from said first multiplier and checking whether the reception signal contains a code error according to said error detection code; an encoder for, upon detection of a code error in said decoder, encoding a retransmission request identifying a frame number which has caused said code error and outputting said retransmission request; a second multiplier for multiplying an output signal from said encoder, by the second diffusion code, so as to be a transmission signal destined to said transmission apparatus; and a transmission/reception block for transmitting and receiving a signal to/from said transmission apparatus, wherein said decoder of said transmission apparatus has a function to instruct said encoder of said transmission apparatus, upon reception of a retransmission request from said reception apparatus, to retransmit the frame to be retransmitted, said encoder of said transmission apparatus has a function, in response to the instruction of retransmission, to read out from said storage an information to be retransmitted and a function to output said information to be retransmitted simultaneously with said information to be transmitted, said transmission apparatus further including a retransmission channel used only for transmitting the information which has been read out from said storage by said encoder so as to be retransmitted, and a third multiplier provided in said retransmission channel, for multiplying a retransmitted information output signal from said encoder, by a third diffusion code so as to be a retransmitted information in a transmission signal destined to said reception apparatus, said transmission channel and said retransmission channel each include a gain controller, both gain controllers being set to maximum when simultaneously processing said information to be retransmitted on said retransmission channel and said information to be transmitted on said transmission channel, and said reception apparatus further including a third multiplier for multiplying a reception signal including the retransmitted information from said transmission apparatus by the third diffusion code so as to be an input signal to said decoder of said reception apparatus to generate a decoded retransmitted information.