Patent ID: 6658071
Filing Date: 2003-12-02
Classification: H04L

Abstract:
A method for detecting symbols in a received signal in the presence of intersymbol interference, the method comprising:performing a forward recursion using a first Viterbi decoder and, at each stage of the forward recursion: selecting forward survivor states; and computing a forward state metric for each selected forward survivor state; performing a backward recursion using a second Viterbi decoder and, at each stage of the backward recursion: selecting backward survivor states; and computing a backward state metric for each selected backward survivor state; and computing soft values for symbols in the received signal by combining the forward state metrics and the backward state metrics; canceling, during the forward recursion, intersymbol interference in the received signal using estimated symbols output by the first Viterbi decoder during the forward recursion; and canceling, during the backward recursion, intersymbol interference using the estimated symbols output by the first Viterbi decoder during the forward recursion.