Performance comparison of interleaving methods in joint frequency-time spreading OFDM-CDMA

OFDM-CDMA using a joint frequency-time spreading method is one of the best candidates for future broadband wireless multimedia communication systems. Different channel-interleaving methods, including bit interleaving and chip interleaving, are investigated. Computer simulations show that the interleaving methods within one OFDM symbol (i.e. only in the frequency domain) can achieve BER performance as good as those within several OFDM symbols (i.e. not only in the frequency domain, but also in the time domain) with less complexity because the joint frequency-time spreading method has already exploited the time diversity.