On the Scheme of Rapid Acquisition of Long PN Code in DSSS Signals

In a direct sequence spread spectrum (DSSS) communication system with long period pseudorandom (PN) code, the acquisition speed of the pseudorandom code will impact the overall performance of the receiving system seriously. A rapid acquisition method of long PN code is proposed, which is based on excellent correlation characteristics of PN code. In this method, the local PN code sequence is extended, folded and averaged, and the DS signal sequence is averaged, then the two result vectors are computed to generate observation vector. The preliminary acquisition of the signal is judged through the threshold of the observation vector. Moreover, the precise acquisition of the signal is completed through removing average and extension. Theoretical analysis and numerical results show that the acquisition method can effectively improve the acquisition speed of the pseudorandom code when searching large-scale codes.