Non-coherent detection for DS spread-spectrum acquisition

Noncoherent detectors for initial code synchronization (acquisition) of binary- and quarternary-phase-shift-keying (BPSK and QPSK) direct-sequence (DS) spread-spectrum signals are analyzed. In addition to the thermal noise, in many applications such detectors are faced with self-noise due to imperfect correlations. Assuming random spreading code sequences, it is shown that the Gaussian approximation to the code partial autocorrelation distribution is very well justified. Based on the theory of circularly symmetric random variables, exact results for the detection performance of BPSK and QPSK schemes are obtained, and handy approximations are devised.