On outage probability analysis of uplink in land mobile satellite cooperative system

In this paper, the outage probability of the uplink is analyzed for a land mobile satellite (LMS) cooperative system, which consists of a satellite (the destination), a mobile terminal (the source) and a relay node on the ground. It is assumed that the source-satellite (S-D) link and the relay-satellite (R-D) link experience independent shadowed Rician fading, and the source-relay (S-R) link experiences Rayleigh fading. The maximal ratio combining technique is used at the destination to combine the direct signal from the source and the relayed signal from the relay with different relaying protocols, such as amplify-and-forward (AF), decode-and-forward (DF) and selection decode-and-forward (SDF). With the trapezoidal rule-based integration approximation method and the moment generating function (MGF)-based approach, the closed-form expressions of the outage probability of the uplink in the LMS cooperative system with three relaying protocols are derived. The analytical results are confirmed by Monte Carlo simulations. The results show that the outage probability of the uplink in the LMS SDF cooperative system is the smallest among three relaying protocols, and the performance of the uplink in the LMS AF cooperative system is better than that of the DF cooperative system when the transmit SNR is high. Moreover, the outage probability of the uplink in the LMS cooperative system with SDF and AF relaying protocols obviously decreases as the channel condition of the S-D link gets better. The performance of the LMS DF cooperative system depends on the channel condition of the S-R link. In addition, the performance of the LMS cooperative system is better than that of the no relay LMS system in most of cases.