Performance of multicarrier CDMA systems using maximal-ratio combining MMSE detection

This paper concerns with the minimum mean-squared error (MMSE) detection of synchronous multicarrier CDMA systems. Maximal-ratio combining (MRC) MMSE detection schemes are proposed for the multicarrier CDMA systems. In the proposed MRC MMSE receiver, the MMSE detection is first performed separately for each carrier, and then the outputs of each MMSE detector are combined in such a way that the resulting signal-to-noise ratio (SNR) is maximized. The performance of the considered MRC MMSE schemes is compared with the conventional MMSE receivers of both jointly and separately designed MMSE filters. It is found that when the system is lightly loaded, the MRC MMSE detection scheme performs comparably to the jointly optimized MMSE detection in the presence of slow frequency-nonselective independent Rayleigh fading for each carrier.