The Receiving Method Based on Signal Separation by Spread Spectrum in the Cooperative System with Step Direct Channel

In high-speed mobile Orthogonal Frequency Division Multiplexing (OFDM) cooperative system, direct channel signal presents a step change due to carriage loss, which interferes with signal reception. In the proposed system, spread spectrum is adopted at relay to separate the receiving mixed signals. Subsequently, the fading coefficient threshold of direct channel is obtained by simulating outage probability of direct channel. Finally, separated direct channel signal is selectively received based on the ratio relationship between its current fading coefficient and the obtained threshold. The proposed receiving strategy reduces Bit Error Rate compared with other receiving methods. Moreover, throughput of the proposed system increases when the fading coefficient is higher than threshold.