Direct-sequence spread-spectrum parallel acquisition in a fading mobile channel

A parallel acquisition scheme for direct-sequence spread-spectrum systems is proposed, and its mean acquisition time performance is analyzed in both nonfading and Rayleigh-fading environments. An expression for the mean acquisition time is derived in terms of the probabilities of detection, missing, and false alarm. These parameters are first analyzed for a typical AWGN (additive white Gaussian noise) channel, then the Rayleigh-fading channel encountered in a typical UHF or microwave land mobile radio channel is studied. The channel is assumed frequency nonselective, and the effect of data modulation and code Doppler is not considered. The performance of the parallel system is compared to the corresponding serial system, and it is shown that a significant improvement can be achieved.<
>