Effects of multiple threshold values in hybrid code acquisition algorithm for direct sequence spread spectrum systems

We propose a hybrid code acquisition algorithm with multiple threshold values for direct sequence spread spectrum (DS-SS) systems, and analyze the algorithm in terms of the detection and the false alarm probabilities. The conventional code acquisition algorithm uses a single fixed threshold value, which is determined at particular SNR, so that it is hard to obtain the optimal performance of the acquisition system. A new decision method proposed in this paper uses multiple threshold values to increase the detection probability. Simulation result shows that our proposed scheme outperforms the conventional one in terms of the detection probability and also that the enhancement of performance is saturated when the number of thresholds is three. From these results, we can see that the use of multiple threshold values compensates for the performance degradation by use of a single pre-determined threshold value in the conventional algorithm.