MAXIMUM-LIKELIHOOD SEQUENCE ESTIMATOR WITH VARIABLE NUMBER OF STATES

摘要

A maximum-likelihood sequence estimator (MLSE) with avariable number of states. A channel response estimatorcalculates channel responses from a received signal having apredetermined burst length and a reference signal. Acontroller checks the latest (L-th) response having a largerpower than a predetermined threshold value of the channelresponses and determines the L number of effective channelresponses having the larger power. A Viterbi equilizer witha variable number of states executes a maximum-likelihoodsequence estimation on the basis of the trellis with M(L-I)states (M is a multi-value number of a modulation signal)using the L number of effective channel responses. The MLSEis operated with the minimum number of states every burst toreduce an average processing amount without degradingcharacteristics and to achieve a low consumption power ofreceivers.