One scheme of cooperative diversity with two satellites based on the Alamouti code

Aiming at the low Earth orbiting (LEO) satellite mobile communication, the cooperative diversity technology is applied to the forward downlink in this paper, and one scheme for cooperative diversity with two satellites based on the Alamouti code is presented. To reduce the non-negligible path delay from the different satellite to the same terminal, the synchronous CDMA is used and satellites are distinguished by the spreading codes which are orthogonal each other in this scheme. Simulation results show the satellite cooperative diversity system can obtain better performance than the traditional uncoded BPSK system with the same fading channel and system parameters. Though the satellite cooperative diversity system has worse performance than the traditional satellite diversity system, it has the advantage in communication range and low complex mobile terminal. Particularly, this new scheme can be used as an effective means to improve the performance in the area where the gateway can not be built.