Adaptive hybrid acquisition with antenna diversity in CDMA systems

Since existing acquisition systems have a fixed threshold value, they are unable to adapt to varying mobile communication environments. This results in a high false-alarm rate or low detection probability. In this paper, an adaptive hybrid acquisition system that adopts an antenna diversity technique and the cell-averaging constant false alarm rate (CA-CFAR) algorithm is presented to acquire a pseudo-noise (PN) signal for CDMA systems. The CA-CFAR algorithm and an antenna diversity technique are adopted to adjust the decision threshold according to environments and to improve detection performance, respectively. The detection probability, false alarm, rate, miss detection probability, and mean acquisition time in the Rayleigh fading channel are derived and compared to those of the conventional hybrid acquisition system with fixed threshold.