Design of a Novel SS (Spread Spectrum) System based on Cooperative Communications

In this paper, we first propose a novel system that combines multi-code spread spectrum modulation (McM) technique with orthogonal frequency division multiplexing (OFDM) employing quadrature amplitude modulation (QAM). This system provides high data transmission rate without reducing spectral efficiency and overcomes the adverse effects of frequency-selective Rayleigh fading by applying a minimum mean square error (MMSE) equalizer at the receiver. Then we deploy the decode-and-forward cooperative communications protocol in the novel system to allow single-antenna users to obtain the powerful benefits of multi-antenna systems. Monte-Carlo simulations are also performed to evaluate the performance of the proposed system