Design of MAI-free MC-CDMA systems over frequency-selective fading channels via codeword selection

A scheme to eliminate completely the multiaccess interference (MAI) of the multicarrier code division multiple access (MC-CDMA) system in a frequency-selective fading environment using codeword selection is proposed. We show that, if the CDMA codewords are chosen to be a proper subset of the Hadamard-Walsh codes, the MC-CDMA system can be MAI-free so that the implementational complexity of the transceiver can be greatly reduced. This MAI-free property is analyzed theoretically and demonstrated via simulation results.