Space-Time Coding for Two-Transmitter and Two-Receiver Cooperation

The single antenna user nodes at the transmitters and receivers share their antennas to form a virtual multiple antenna system and to realize the cooperative diversity. So it can enlarge the system´s capacity and enhance the service quality of the ad hoc network and improve the system´s performance. Applying the orthogonal property of the space-time coding, we transform the vector signal jointly maximum likelihood (ML) decoding into single symbol decoding, and we provide the single symbol decoding methods for the situations in decode and forward mode (DF) and in amplify and forward mode (AF) separately. After smoothing the noise influence, we can improve the system´s performance. Simulation demonstrates that the application of user´s cooperation diversity can effetely improve the system´s performance. And given the total power, suitably adjust the target signal power and cooperative signal power, the performance in AF mode approaches that in DF mode. So, the space-time coding in AF mode is a good choice.