PN code acquisition with adaptive antenna array and adaptive threshold for DS-CDMA wireless communications

An efficient PN code acquisition scheme with an adaptive antenna array and adaptive threshold is proposed. The basic structure is the combination of a conventional PN correlation searcher, an adaptive beamformer and an adaptive threshold setting circuit. The proposed scheme employs all the array element outputs in the PN correlation searcher and also uses an adaptive threshold for each PN code phase hypothesis testing by estimating the instantaneous power prior to PN code despreading. The performance of the proposed scheme is theoretically analyzed and also simulated in terms of the false alarm probability P_f, detection probability P_d and average acquisition time T_acq under a Rayleigh mobile fading environment. Theoretical and simulation results show that the proposed scheme is robust against received signal power variations and can significantly improve the PN code acquisition performance