A differential Alamouti coding scheme for OFDM based asynchronous cooperative systems

In this paper, we present a differential OFDM Alamouti coding based transmission scheme for two relay cooperative system. The relay nodes, only need the time-reversion, some sign changes, the complex conjugation to the received signals, and no IFFT or FFT is needed. At the destination node, decoding is achieved with low decoding complexity based on differential Alamouti code. Simulation results show that the differential scheme is a little worse than coherent detection without the channel state information (CSI).