An improved hybrid PN code acquisition for CDMA personal wireless communications

This paper proposes an improved decision strategy for noncoherent hybrid parallel pseudonoise (PN) code acquisition and analyzes the acquisition performance in the presence of multiple access interference (MAI) over Rayleigh and Rician fading channels for code-division multiple access (CDMA) personal wireless communications. The hybrid acquisition scheme combines parallel search with serial search to cover the whole uncertainty region of the input code phase. The closed-form expressions of the detection and false-alarm probabilities and mean acquisition time are derived. It is shown that, (i) the scheme achieves both better acquisition performance and simpler acquisition hardware structure than total parallel acquisition in the case of severe MAI, and (ii) the increase of the mean acquisition time (due to MAI) depends on the number of users in the CDMA system, PN code search strategy, system design parameters, and channel fading statistics