Communication arrangement and method with fast tracking receiver for spread spectrum signals

Abstract

A fast-tracking discrimination approach provides rapid acquisition useful for direct-sequence spread spectrum applications. In one example embodiment, the present invention is directed to a communication system receiver that operates a linearly normalizing discrimination process on a signal modulated by a waveform having a bit rate defined in terms of a bit-pulse duration (chip). For at least one reference code, correlation results are obtained from several timing offsets of the signal, where each timing offset is separated by a fixed chip offset. Using at least three consecutive ones of these correlation results, assuming that the correlation energy of band-limited signals is approximately quadratic, an accurate phase error is obtained for synchronizing the received signal. When this embodiment is used in an optimal variable gain filter, the receiver outperforms the normalized classical early-late discriminators despite the unrealistic assumption that such classical discriminators have an exact priori knowledge of the received signal power.