In this article, we propose a multiple-input-multiple-output, orthogonal frequency division multiplexing, codedivision\r\nmultiple-access (MIMO OFDM-CDMA) scheme. The main objective is to provide extra flexibility in user\r\nmultiplexing and data rate adaptation, that offer higher system throughput and better diversity gains. This is done\r\nby spreading on all the signal domains; i.e, space-time frequency spreading is employed to transmit users� signals.\r\nThe flexibility to spread on all three domains allows us to independently spread users� data, to maintain increased\r\nsystem throughput and to have higher diversity gains. We derive new accurate approximations for the probability\r\nof symbol error and signal-to-interference noise ratio (SINR) for zero forcing (ZF) receiver. This study and simulation\r\nresults show that MIMO OFDM-CDMA is capable of achieving diversity gains significantly larger than that of the\r\nconventional 2-D CDMA OFDM and MIMO MC CDMA schemes.
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