VITERBI DECODING METHOD, DECODER, MOBILE STATION RADIO DEVICE, BASE STATION RADIO DEVICE AND MOBILE COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a viterbi decoding method capable of acquiring a correct decoding bit sequence with the less number of times of trace-back, a decoder, a mobile station radio device, a base station radio device and a mobile communication system. SOLUTION: A start state memory 110 is provided on an error correction decoder 102, a path metric being likelihood of a surviving path is stored for the surviving path of all time points and of all states during ACS arithmetic operation, the starting state of the ACS arithmetic operation (time point S) of the surviving path is stored in a start state memory 110. After the completion of ACS processing, a trace-back control circuit 113 performs tracing back at only a state satisfying (state at ACS arithmetic operation completion (time point E))=(start status of ACS arithmetic operation start time point), thereby avoiding useless trace-back processing. COPYRIGHT: (C)2006,JPO&NCIPI