Patent ID: 6233290
Filing Date: 2001-05-15
Classification: H03M,H04L

Abstract:
In a communication system receiving from a channel a received signal corresponding to a succession of received symbols during a corresponding succession of symbol times, said succession of symbols corresponding to a succession states of a code of said communication system, each of said states branching to a predetermined number of others of said states, a process for deducting an estimate of said succession of symbols from said received signal by overlapped observations of said received signal, said process comprising:storing a block of symbols of said received signal;for each one of said states at a current symbol time of said received signal, identifying a previously stored survivor path of states corresponding to said received signal leading to said one state and forming plural candidate paths from said one state by appending to said survivor path next ones of said states branching from said one state;for each one of said plural candidate paths, computing a path metric comprising a sum of products of symbols corresponding to said succession of states in one of said plural candidate paths and a corresponding succession of symbols in said received signal extending back from a next state of said one candidate path over a predetermined number of prior symbol times;for each of said next ones of said states, selecting one of said plural candidate paths having the greatest path metric as said survivor path to a corresponding next state and storing said survivor path to said one next state; andoutputting a symbol of a survivor path corresponding to an earlier symbol time displaced from a current symbol time by a predetermined delay.