METHODS AND APPARATUS FOR SIGNAL SEARCHING USING CORRELATION

摘要

A signal searcher for a CDMA communications system has a reference signal generator and a correlator to correlate a reference signal with a received signal in short (signal-coherent) correlation intervals. The code phase of t he reference signal is changed through all of N possible code phases in N successive correlation intervals constituting one signal scan cycle. The correlation results for the same code phase for a plurality of the correlati on intervals are accumulated over successive signal scan cycles using a combine r and buffer, and the presence and code phase of one or more desired signals i n the received signal are determined by a decision unit in dependence upon the accumulated correlation results. In one embodiment all of the correlation results are accumulated; in other embodiments memory requirements are reduce d by accumulating only larger values of the correlation results.