Maximum likelihood combining for MC-CDMA

Abstract

This paper proposes a novel maximum likelihood combining (MLC) scheme for MC-CDMA systems. Currently, minimized mean square error combining (MMSEC) is widely considered the best combining scheme for MC-CDMA. The MLC proposed in this paper is optimal from the standpoint of minimizing the probability of error performance. It is shown that MLC is very close to MMSEC in a fully loaded system, justifying the selection of MMSEC over other combining schemes. Moreover, when the load is small (as measured by number of users), MLC is shown to outperform MMSEC (and, other combining schemes).