A Unified Analysis and Comparison of Long PN-Code Acquisition Techniques for AWGN and Multipath Fading Channels

Direct Sequence Spread Spectrum is a solution for providing security and jamming resistance in wireless communications. Using long spreading codes is a good idea for making DSSS more secure and reliable. In this paper, common methods of long code acquisition are reviewed and discussed analytically and numerically. The effect of residual frequency and coherent integration time on their probability of detection and mean acquisition time in an AWGN channel are simulated and computational burden of each algorithm is roughly obtained. From theoretical point of view, in addition to restating the expressions of the methods in uniform framework for AWGN channel, performance analysis for averaging based methods in AWGN channel are carried out. Also the effect of multipath Rayleigh channel on detection performance of the methods are modelled mathematically and simulated. Beside good agreement between theory and simulation, the results show that Dual folding method provide better trade-off between time and detection performance and passing through a typical fading channel causes a few dBs drop in the performance of the methods. This paper provides a comparison between acquisition techniques of long codes so as choosing a method for a specific application while considering trade-offs between metrics would be feasible.