Research On Cooperative Diversity Technology Based On Satellite Mobile Terminals

Satellite mobile communication has been widely applied in emergency rescue, personal mobile communication and so on. Using cooperative diversity technology, mobile satellite communication system can combat fading effectively and improve coverage of system.In this paper, we introduce this system architecture and channel characteristics. These researches can provide system model for this paper. Aiming at the cooperative diversity technology based on satellite mobile terminals, several relaying modes, combining methods and power allocation schemes are analyzed respectively in detail. Through the researches, we can find the optimal relaying mode and combining method, which can increase the system’s reliability performance.This paper focuses on power allocation scheme in cooperative diversity communication based on satellite mobile terminals, including two perspectives:minimizing outage probability and transmit power consumption. Firstly, we illustrate a significant advantage of the outage performance based on outage-optimal power allocation scheme. Secondly, this paper proposes an adaptive power allocation scheme aiming at minimizing total transmit power consumption for land mobile satellite (LMS) cooperative communication systems through amplify-and-forward (AF) protocol. In LMS uplink, the cooperative opportunity, which is defined as the selection between direct transmission and the cooperative transmission, is introduced into this scheme. With the variation values of the fading degree, the transmit power of user terminals can be allocated adaptively subject to a signal to noise ratio (SNR) threshold constraint. As a consequence, simulation results show that the adaptive power allocation scheme provides an outstanding performance aiming at minimizing the total transmit power consumption under a SNR threshold constraint.