Adaptive power allocation scheme for land mobile satellite cooperative communication systems under a SNR threshold constraint

Power resource is one of the extremely limited resources of user terminals. 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. Numerical results are given in order to illustrate a significant advantage of total transmit power consumption based on adaptive power allocation scheme over conventional cooperative power allocation scheme and direct transmission.