A blind joint estimator for multipath diversity and PN timing error in direct-sequence spread-spectrum receivers

A blind joint estimator for multipath diversity and PN code timing error is proposed in this paper for direct-sequence spread-spectrum signaling on a frequency-selective fading channel. In the multipath diversity combiner, a modified known modulus adaptive (KMA) algorithm is used to cope with time-varying multipath effects and to perform multipath diversity combining in the blind mode. In the code timing recovery, the timing error signal is extracted from each propagation path independently and also combined in the same fashion as the multipath diversity combining process. By taking advantage of the inherent diversity based on a known modulus adaptive (KMA) algorithm, this modified code timing recovery can avoid the problem due to the drift or flutter effects of the error signals, and provide better performance on frequency selective fading channels. Extensive computer simulation results have verified the analysis and indicated very attractive behavior of the proposed joint estimator for multipath diversity and PN code timing error.