Real CDMA-OFDM/OQAM transmission system based on Walsh Hadamard spreading code over Rayleigh fading channel

In this paper, we investigate the combination of Orthogonal Frequency Division Multiplexing with Offset Quadrature Amplitude Modulation (OFDM/OQAM) with spread spectrum Code Division Multiple Access (CDMA) transmission scheme as an alternative to classical Multicarrier-CDMA (MC-CDMA) system over multipath fading channel. The performance of real CDMA-OFDM/ OQAM transmission system with Walsh Hadamard spreading code is directly linked to the performance of OFDM/OQAM system. OFDM/OQAM performs better than CP-OFDM and CDMA-OFDM/OQAM outperforms conventional MC-CDMA thanks to the no use of the Cyclic Prefix and the good choice of the prototype filter. We present the simulation results of the performance of OFDM/OQAM system with Isotropic Orthogonal Transform Algorithm (IOTA) prototype filter compared to conventional CP-OFDM system and the performance of the combination CDMA-OFDM/OQAM compared to MCCDMA. The performance is derived by computing the Bit Error Rate (BER) as a function of the transmit signal-tonoise ratio (SNR).