Analysis and performance evaluation of synchronous trellis-coded CDMA for satellite applications

In this paper synchronous trellis-coded code division multiple access (S-TC-CDMA) for satellite communications is introduced and analyzed. Compared with asynchronous CDMA (A-CDMA) and uncoded synchronous CDMA (S-CDMA) systems, S-TC-CDMA improves the power and/or the bandwidth efficiency by using trellis-coded PSK or QAM modulation in conjunction with independent orthogonal I-Q direct sequence spectrum spreading (DS/SS). An approximate formula for the bit error rate performance of S-TC-CDMA in the AWGN channel with co-channel interference is derived and favorably compared to computer simulation results. Finally, the system performance degradation due to the satellite nonlinearities and multipath fading is investigated.