An adaptive double-dwell PN code acquisition system in DS-CDMA communications

An adaptive double-dwell acquisition system for pseudo-noise (PN) sequences is presented for direct-sequence spread-spectrum (DS-SS) systems. Since existing acquisition systems have a fixed threshold value, they are unable to adapt to varying mobile communication environments resulting in a high false alarm rate or low detection probability. Accordingly, this study presents an adaptively varying threshold scheme that uses a constant false alarm rate (CFAR) algorithm. The performance of the proposed system is compared to the conventional double-dwell system based on deriving formulas for the detection probability, false alarm rate, and mean acquisition time of the proposed system. The results confirm that the proposed system can produce a highly improved performance over the conventional system.