Jun Mitsugi

Path-search algorithm introducing path-management tables for a DS-CDMA mobile terminal

Generally, in a DS-CDMA receiver, the received multipath fading signals are resolved into each path having different time-delay with a searcher and then combined to generate original signal with a Rake combiner. One of the most important design objectives of the Rake combiner is how to search the paths accurately. Particularly from the viewpoint of power dissipation, the searcher operates during a discontinuous path-search mode only, i.e., it can turn power on/off periodically according to the time slot, to save the battery. However, as this period for performing the path search becomes longer, accuracy of the path detection deteriorates. In this paper, a path-search algorithm that improves the path-detection accuracy without shortening the path-search period is proposed. Path detection was carried out by the proposed method utilizing the delay profile detected in the path searcher, the combined signal in the Rake combiner, and also three management tables for paths-data. Computer simulation results show that the proposed approach performance is superior to that of the conventional path-search method.