Performance of 16-state TCM MC-CDMA with various SUD techniques over downlink wireless channels
Abstract
We present a novel combination of 16-state 8-phase shift keying/8- quadrature amplitude modulation (8-QAM) trellis coding schemes with multicarrier code division multiple access (MC-CDMA) and various single user detection (SUD) techniques. In literature, it is well established that minimum mean square error (MMSE) is the optimum SUD technique when used with fully loaded uncoded MC-CDMA systems. We show that for fully loaded systems, 8-QAM trellis-coded MC-CDMA equalised with threshold orthogonality restoring combining (TORC) outperforms equivalent systems that use MMSE by almost 1.4 dB at a bit error rate of 10-5. Conversely, it is known that single user loaded uncoded MC-CDMA equalised with maximum ratio combining provides best performance among all SUD methods. We report that among all possible combinations of the underlying trellis-coded modulation, MC-CDMA and SUD techniques, TORC equalised 8-QAM trelliscoded MC-CDMA systems provide the best performance as they do for fully loaded systems. Hence, this combination appears to be a promising candidate for both downlink and uplink channels.
Keywords
References
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