Concatenated trellis coding and full response CPM for wireless DS/SSMA communications

In this paper, a direct sequence spread spectrum multiple access (DS/SSMA) system employing serially concatenated trellis-coded modulation (TCM) and continuous phase modulation (CPM) techniques over a flat Rayleigh channel is presented. In this concatenated coded modulation scheme, TCM and CPM can be equivalently regarded as outer and inner codes, respectively. The inner code gives desirable spectral efficiency and coding gain by using a maximal likelihood sequence estimator. The outer code contributes significant gain to the DS/SSMA system. The performance of the concatenated TCM/CPM DS/SSMA system is studied and demonstrates that this DS/SSMA system can achieve significant improvements in bit error probability over the conventional DS/SSMA with TCM and the DS/SSMA system using CPM format under the same conditions