Performance Analysis of CDMA-OFDM System via Cooperative Communication in Wireless Channel

Signal distortion due to the path loss, shadow, and multi-path fading is very serious in radio channel. In this paper, we propose CDMA-OFDM cooperative communication system based on DFP (decode and forward protocol) to overcome these phenomena using spread spectrum technique, orthogonal subcarrier, and the space diversity. We simulated proposed system under Rayleigh flat fading channel environment. A variety of simulation results reveal the cooperation can provide performance gain of up to 12 dB over direct communications in ideal inter-user case at BER of 10^-3 . And we can also confirm variation of diversity effect as channel environment changes.