Sequential acquisition of PN sequences for DS/SS communications: design and performance

The performance of sequential acquisition of m sequences, based on the sequential probability ratio test (SPRT), is studied. The authors consider a sliding correlator-type structure for the acquisition scheme, which the mean acquisition time is proportional to the average number of samples used for a synchronization test. Sequential acquisition requires the knowledge of the partial correlation of the pseudonoise (PN) sequence, however, as the partial correlation of an m sequence is difficult to model the authors propose an approximate upper bound. This is then piecewise linearized and used for designing the SPRT which is then compared to the fixed-dwell time technique, a scheme using the fixed sample size test. Numerical results show that the saving of acquisition time by the SPRT increases as the desired probabilities of errors and/or the input SNR decrease. Analytic results are verified by computer simulation.>