Effects of Ricean fading and data modulation on noncoherent PN sequence sequential acquisition schemes

The authors investigate the performance of various pseudonoise (PN) sequence acquisition schemes with data modulation in a Ricean fading channel. In particular, the fixed sample size test and the truncated sequential probability ratio test are studied in detail. In previous studies of sequential acquisition tests, the integrators in the correlation process were reset periodically to generate i.i.d. (independent and identically distributed) samples, which introduces loss in the effective signal-to-noise ratio and hence degrades the system performance. The authors do not reset the integrators, and their decision samples are neither independent nor identically distributed. The probability density functions of the decision statistics are determined, and the decision thresholds for achieving the design false-alarm and miss probabilities can be calculated. However, the average sample size of a sequential test does not have a closed-form analytical solution, but is evaluated by simulation