Parallel acquisition of PN sequences in Rayleigh fading channel and the application to the multi-carrier CDMA systems

We propose an improved scheme for parallel acquisition of PN sequences of multi-carrier direct-sequence spread spectrum systems in the Rayleigh fading channel. Unlike conventional parallel acquisition schemes, the search region of each searcher in the proposed scheme is modified so that it is overlapped with that of other searchers. The use of the proposed search scheme enables us to obtain multiple information on the same code phase at different time instants, providing the time diversity effect. This effect results in acquisition performance robust to fading. The performance of the proposed acquisition scheme is analytically evaluated in terms of the detection probability and the mean acquisition time in the Rayleigh fading channel. Numerical results show that the proposed scheme can provide acquisition performance robust to channel conditions, including fading and correlation between the subchannels.