Trellis demodulation of two-level Reed-Solomon-modulated FH-CDMA wireless communication systems

Frequency-hopping code-division multiple access (FH-CDMA) along with coded modulation using Reed-Solomon (RS) codes has recently been proposed for wireless communications to increase data transfer rate. In this paper, an improved method of implementing the modulation and demodulation of the RS codes in RS/FH-CDMA by means of a trellis and the Viterbi algorithm is proposed and analyzed. We study an efficient algorithm for “pruning” the trellis to decrease demodulation errors. Our pruned-trellis method reduces modulation complexity and substantially simplifies the demodulation process. Finally, the performance of this trellis-based RS/FH-CDMA system is analyzed and compared with the old system without trellis.