Patent ID: 6314387
Filing Date: 2001-11-06
Classification: H03M,H04L

Abstract:
A method of estimating a sequence transmitted by a sender by using a Viterbi algorithm to select surviving paths from paths indicating transitions of states of combinations of data at a first instant up to a second instant and by estimating the sequence from a received signal and from characteristics of a channel, said method comprising the steps of:calculating path metrics of paths going from states at the first instant to states at the second instant;deriving modified paths that are modifications of the paths going from the states at the first instant to the states at the second instant;calculating the path metrics of the modified paths derived by the modified path-deriving step;correcting the paths going from the states at the first instant to the states at the second instant according to results of the calculations performed by the first and second path metric-calculating steps;determining a surviving path going to the states at the second instant from the plural paths going from the states at the first instant to the states at the second instant through paths corrected by the path-correcting step;performing the first path metric-calculating step, the modified path-deriving step, the second path metric-calculating step, the path-correcting step, and the surviving path-determining step for each of the states of combinations of the plural data items at the second instant;then selecting a final path from surviving paths determined for each of the combinations of the data items at the second instant according to path metrics of the surviving paths; andestimating a signal sequence obtained from the final path selected by the final path-selecting step as the transmitted signal sequence.