Acquisition Time Analysis of Noncoherent PN Sequence Acquisition Schemes

In direct-sequence spread-spectrum systems, successful communications require phase synchronization of the incoming pseudonoise PN coded waveform with a locally generated replica at the receiver. It has been previously shown that sequential PN code acquisition schemes have the potential to achieve the best performance, but they are the least analyzed because of the analytical difficulties. The acquisition time for a PN code acquisition scheme is an important parameter for system design purposes. This thesis investigates the performance of two acquisition schemes in terms of the acquisition time. A fixed sample size FSS test and a truncated sequential probability ratio test TSPRT are studied with noncoherent demodulation in a classical additive white Gaussian noise AWGN channel and in presence of fading. Optimal selection of desired detection and false alarm probabilities, the effects of penalty time, majority logic verification schemes and channel signal to noise ratio SNR mismatch problems are thoroughly studied using the flow graph technique. Our results show that the TSPRT is efficient, robust against fading, fast and suitable for real time low cost implementations.