PERFORMANCE EVALUATION OF DS CDMA HYBRID ACQUISITION IN MULTIPATH RAYLEIGH FADING CHANNEL/

In this paper, the evaluation of a hybrid acquisition performance has been considered for the pilot signal in direct sequence code division multiple access (DS/CDMA) forward link. The hybrid acquisition is intr oduced by the combination of two schemes, parallel and serial acquisit ions. The mean acqusition time of the hybrid acquisition scheme is der ived to consider both case 1 (the correct code-phase offsets are inclu ded in one subset) and case 2 (the correct code-phase offsets exist at the boundary of two subsets), which are caused by the distribution of the correct code-phase offsets between two subsets. Detection, false alarm, and miss probabilities are derived for the cases of multiple co rrect code-phase offsets and multipath Rayleigh Fading channel. Result s are provided for the acquisition performance with respect to system design parameters such as postdetection integration length in the sear ch and verification modes, subset size, and number of I/Q noncoherent correlators. Also, comparision between hybrid acquisition and parallel acquisition under the same hardware complexity is provided in terms o f the minimum mean acquisition time.