Impact of MIMO enabled relay on the performance of a hybrid satellite-terrestrial system

In this paper, we investigate a hybrid satellite terrestrial system with multiple input and multiple output enabled fixed relay, which is more reliable than the conventional dual-hop multiple single input and single output relaying network. Providing a small number of antennas on a fixed relay is easier to undertake than setting up on a mobile terminal due to the size limitation. In this study, we consider the impact of cooperating fixed relay with multiple transmitting and receiving antennas on the hybrid satellite-terrestrial system. Amplify-and-forward cooperative protocol is used at the relay node while for signal combining at the relay node, maximum ratio combining and maximum ratio transmission techniques are used. Independent and non-identically distributed fading channels, shadowed Rician, and Nakagami-\(m\), are assumed between the source-relay and relay-destination links respectively. An analytical approach is derived to evaluate the performance of the system in terms of outage probability, symbol error rate (SER) and ergodic capacity. The closed form expressions for the probability density function, cumulative distribution function, moment generating function, average SER of the total end-to-end signal-to-noise ratio are derived. We further derive the approximate closed form expression of ergodic capacity. These derived analytical expressions are applied to the general operating conditions together with available satellite channel data of various degrees of shadowing. The analytical results are compared with Monte Carlo simulations. The results show the improvement in the performance of the hybrid satellite-terrestrial system under various antenna arrangements at the relay node.