Hybrid Satellite-Terrestrial Cooperative Communication with Mobile Terrestrial Nodes

This work investigates the performance of hybrid satellite-terrestrial systems over time-selective fading links arising due to the node mobility with multiple relay based selective decode-and-forward cooperation. The aerial satellite-to-relay and satellite-to-destination links are non-identical time-selective shadowed Rician fading in nature, whose parameters depend on the elevation angle of the satellite, whereas the terrestrial relay-destination links are assumed to be non-identical time-selective generalized Nakagami faded. Closed form expressions are derived for the per-frame average symbol error rate (SER) and asymptotic SER floor considering the transmission of M-ary PSK modulated symbols. It is observed that the time-varying nature of the links significantly degrades the system performance. Further, the impact of the satellite elevation angles at the terrestrial nodes is explicitly demonstrated through simulations, along with the effect of preamble versus midamble for channel estimation. The error rate of the system is seen to reduce significantly with increasing satellite elevation angle at the relay when the satellite-destination link experiences frequent heavy shadowing (FHS) and the relay-destination links are relatively strong. However, for other scenarios when the relay-destination links are relatively weak and satellite-relay links experience FHS, significant performance improvement can be seen by increasing the satellite elevation angle at the destination UE.