Relay selection-based hybrid satellite-terrestrial communication systems

The problem of relay selection in amplify-and-forward (AF)-based hybrid satellite-terrestrial cooperative communication systems is considered. A partial relay selection scheme is studied in which satellite selects a relay earth station (ES) among multiple relay ESs (situated on ground) on the basis of maximum instantaneous signal-to-noise ratio (SNR). Satellite-relay ESs are assumed to follow Shadowed-Rician fading, whereas relay ESs-destination ES links (terrestrial links) are assumed to follow Nakagami-m distribution. First, the cumulative distribution function and probability density function (PDF) of the maximum instantaneous SNR of satellite-relay ESs links are derived; then by using this PDF, the expression of moment generating function (MGF) of the received instantaneous SNR at destination ES is obtained. The average error performance of the considered system with the proposed relay ES selection is derived in terms of Meijer-G functions by using MGF approach. In order to get the diversity order of the relay ES selection-based AF scheme, the asymptotic PDF of the considered scheme is derived, and then by using this asymptotic PDF, the analytical diversity order of the system is obtained. It is demonstrated by the analysis and simulation that the performance of the AF-based hybrid satellite-terrestrial communication systems can be significantly improved by deploying more relay ES at the ground in between satellite and destination ES.