Adaptive acquisition of multiple access codes

Most families of codes used in code division multiplexing have a large number of autocorrelation side lobes which lead to false acquisitions, particularly when the received signal is strong. In this paper, an adaptive acquisition scheme is proposed for the initial acquisition of direct sequence (DS) spread spectrum (SS) systems using multiple access codes. The proposed algorithm considerably increases the high signal acquisition performance at the expense of a small decrease in low signal performance, thereby increasing the range in the carrier-to-noise ratio (C/No) over which the SS system can operate. The performance of the proposed algorithm is compared with conventional, fixed-threshold, serial-search acquisition for a DS SS multiple access system employing a family of Gold codes.