Patent ID: 7159167
Filing Date: 2007-01-02
Classification: H03M

Abstract:
1. A method for decoding a convolutionally coded signal in a receiver, using a search through a trellis, in which at each stage of the trellis a certain set of state indexes of the stage are selected for continuation, the method comprising, at each stage of the trellis: defining more than one unequal threshold value for the values of the state indexes, each threshold value defining one state index group, calculating for each state index a path metric, arranging the calculated state indexes into different state index groups by comparing the path metric value of the state index with the threshold values, and selecting state indexes for continuation from the state index groups in such a manner that starting from the state index group comprising the highest state indexes, state indexes are selected from the state index group comprising the highest state indexes in a random order until all the state indexes of the group have been selected, then continuing to select the state indexes from the next state index group, and repeating this until a certain number of state indexes have been selected.