A new serial search acquisition approach with automatic decision threshold control

A new approach to pseudo noise (PN) code acquisition for a code division multiple access (CDMA) direct sequence spread spectrum system is presented and analyzed. The new approach adaptively estimates the optimal threshold by exploiting the signal and noise statistics, uses the threshold to make a decision to stop or to continue the search process by employing pre-verification logic, and obtains fast acquisition. The paper also develops the mean acquisition time of the new algorithm and illustrates the optimum system parameter design methodology through a performance analysis. The considerable advantage of this approach compared to conventional approaches is demonstrated. By combining the maximum likelihood approach with a serial search approach, a faster acquisition is achieved. The new acquisition system uses, in each dwell, an adaptive signal detection threshold for signal detection and an adaptive signal classification threshold for classifying a signal versus noise.