Performance of Residue Number System Based DS-CDMA over Multipath Channels Using Orthogonal Sequences

摘要

This paper is concerned with a new direct-sequence spread-spectrum multiple-access communication system based on the so-called residue number system (RNS) or redundant residue number system (RRNS). The system operates in a multipath fading environment, and a RAKE receiver structure with maximum ratio combining is used for demodulation. Approximations to the error probabilities are given by using Gaussian statistics for the multiple-access and the multipath interference. Concatenated codes employing residue number system product codes (RNS-PC) as the inner codes and nonbinary Reed-Solomon (RS) codes as the outer codes are adopted to improve thc system performance. The performance of the system is determined for a range of different length RNS-PC schemes. The results show that, for a given outer RS code and a given number of moduli of the inner RNS-PC, the performance of the system ean be optimized by varying the relative number of information moduli and redundant moduli of the inner RNS-PC and the moduli's values.