Performance of convolutional and RS codes in DS-CDMA systems using space-time MMSE multiuser detection

In this paper we investigate the performance of a minimum mean square error (MMSE) multi-user detector (MUD) using antenna array processing and forward error correction channel codes (FEC) in a synchronous direct-sequence code-division multiple access (DS-CDMA) system over both additive white Gaussian noise (AWGN) and flat Rayleigh fading channels. Two different channel codes are considered in a binary phase shift-keyed (BPSK) modulation system; Reed-Solomon (RS) and convolutional codes. Through computer simulations, a comparison between the two codes shows that convolutional codes and soft decision decoding can offer at least 2 dB coding gain over the hard decision RS decoding in an AWGN channel and approximately a 5 dB gain in a flat fading channel at a BER of 10^-4. In the paper, such results are compared with these in the text (Wicker 1995) for the single user case and AWGN channels