MIMO two-way relay communication based on Alamouti code

This paper presents a new scheme for demodulate-and-forward two-way relaying scheme based on Alamouti code. Two nodes, A and B, employ Space-Time Alamouti code to transmit their messages to each other through relay node (RN). The RN receiver uses Minimum Mean Square Error Successive Interference Cancellation (MMSE-SIC) to separate signals originating at nodes A and B. The RN transmitter applies XOR to combine the two received demodulated signals, the composite signal is modulated and broadcasted using Alamouti Code. The proposed scheme does not require Channel State Information (CSI) at the transmitters of A, B and RN. Furthermore, If the number of antennas at each of nodes A and B is two, then RN requires two antennas to separate the two signals. As the number of antenna increases at relay node, the performance of the system improves significantly.