Using higher order constellations with minimum mean square error (MMSE) receiver for severe multipath CDMA channel

Third generation wireless systems are expected to be characterized by high data rates and multimedia traffic. This paper is a preliminary investigation to determine if two dimensional higher order constellations, in conjunction with code division multiple access (CDMA), can be used to support the data communication needs of such systems. We compare the performance of QPSK and 16-QAM in a high multipath environment when either conventional matched filters (MF) or minimum mean square error (MMSE) receivers are used. We substantiate the results of semi-analytical calculations of the error rate with simulations, and conclude that the use of a higher order constellation can improve the system performance when the multipath is sufficiently severe.