I-QTCM QPSK synchronous DS/CDMA over frequency-selective multipath Rayleigh fading channels with selection diversity

This paper considers the application of I-Q trellis coded modulation (TCM) techniques to synchronous direct sequence code division multiple access (S-DS/CDMA) communication over frequency-selective fading mobile radio channels. The effect of the optimum adaptive coherent RAKE receiver structure with selection of the largest outputs is studied and an exact analytical expression for the pairwise error probability is obtained. This expression is used to evaluate the average BER upper bound through the transfer function bounding technique. The influence over the average BER of various system parameters like the number of active users, the number of selected outputs or sequence length are considered.