Patent ID: 7450668
Filing Date: 2008-11-11
Classification: H03M,H04L

Abstract:
1. A method of decoding data transmitted via a communication channel, the method comprising: determining a first partially collapsed metric value for each bit in a symbol transition, each first partially collapsed metric value being a cumulative metric of starting in a first state and ending in a second state in L transitions with the respective bit in the symbol transition being a first value, the first state and the second state being internal states of a Viterbi algorithm, wherein the first partially collapsed metric value is equal to the cumulative metric value for each of the states plus first minimum sum of branch metric values; determining a second partially collapsed metric value for each bit in the symbol transition, each second partially collapsed metric value being a cumulative metric of starting in the first state and ending in the second state in L transitions with the respective bit in the symbol transition being a second value, the second value differing from the first value; for each bit in the symbol transition, determining a relative likelihood value based on its respective first partially collapsed metric value and its respective second partially collapsed metric value; and