APPARATUS AND METHODS FOR RECEIVING INFORMATION USING VARIABLE LENGTH ACCUMULATION SEARCHERS

摘要

Delays in a spread spectrum signal transmitted in a communications medium according to a spreading sequence may be determined by receiving a composite signal including the spread spectrum signal from the communications medium. The composite signal is correlated with the spreading sequence according to a first correlation length, to produce first time-offset correlations of the composite signal with the spreading sequence. Selected ones of the first time-offset correlations of the composite signal then are further correlated with the spreading sequence according to a second correlation length that is longer than the first correlation length, to produce second time-offset correlations of the composite signal with the spreading sequence. At least one of the second time-offset correlations may be selected. By providing variable length accumulation searchers, power and/or processing time can be saved by performing limited correlations for those delays that do not appear to be qualified candidates to be ultimately selected.