A path restricted sequence estimator using codeword characteristics

This paper proposes a new approach for a sequence estimator to utilize redundancy of transmitted data more effectively. The main concept of the proposed estimator is that it compares only the path metrics of transition paths which agree with the coding rules of modulation in the sequence estimation process. The concept has been found to be effective even for a sequence estimator with decision feedback loops such as a DDFSE, for error propagation can be suppressed. Simulation results, using CCK as a codeword, show that the proposed estimator's packet error rate performance is superior to that of a DDFSE with a codeword correlator, with a 19% improvement in multipath tolerance and 3.5 dB improvement in noise tolerance.