A low-complexity multitone-CDMA communication technique

Digital implementation of multitone(MT-) CDMA systems often involves considerable complexity. Assuming the spreading-sequence length, N , is a multiple of the number of subcarriers, M , this paper proposes a new digital MT-CDMA technique that achieves lowimplementation complexity. In particular, for the case of rectangular chip waveform, it is shown that the MT-CDMA technique proposed earlier and the technique proposed in this paper require a + a log, aN and 1 + (M/N)log, M multiplications per chip, respectively, where a 2 1 is the number of samples per chip. The reduction in complexity is particularly considerable when N is large.