Multi-symbol accumulation maximum-selection method in fast code acquisition of DSSP systems

Pseudonoise (PN) code acquisition in a short period of time with high detection probability is required and challenging in short frame burst-mode direct-sequence spread-spectrum (DSSS) systems. A novel noncoherent approach to PN code acquisition, based on digital matched filters (DMFs), is proposed to solve the problem. It is an improved mode of the traditional maximum-selection method. By using the method of multi-symbol accumulation cell instead of the dwell and verification cell, the proposed algorithm can increase the speed of code acquisition without channel estimation, and suggests itself as an attractive approach in high-speed applications. Its performance in QPSK-DSSS systems, as well as its impact on factors such as frequency shift, signal noise radio (SNR) and spreading factor on detection probability have also been shown. The measurement results show that this algorithm is able to capture PN code fastly in the presence of moderate frequency shift under the conditions of low SNR.