Efficient DSSS burst synchronization methods

This paper treats the synchronization of packetized (burst like) direct sequence spread spectrum (DSSS) signals. Burst lengths up to 200 bits with binary phase shift keying (BPSK) modulation are considered. Under the condition of receive signal levels below the noise level this is a very critical enterprise as rapid burst detection and acquisition techniques are needed. Assuming that the pseudo noise (PN) code length is identical to the spreading factor, a filter matched to the PN code (named PN matched filter) can be used for both acquisition and tracking. Though the use of matched filtering for transmission purposes has a long tradition, only in recent years the realization of digital wide band and high order finite impulse response (FIR) filters has grown to state of the art due to steady progress in semiconductor and very large scale integration (VLSI) techniques. Digital filtering has developed in a way that allows storage and real time processing of complete PN codes as a set of filter coefficients and therefore, the despreading of DSSS signals.