Performance Evaluation of Decode-and-Forward Satellite Relaying

In this paper, we consider decode-and-forward (DF) relaying of the data of a multiple-antenna-based source Earth station, via a single-antenna-based satellite, to a multiple-antenna-based destination Earth station. The source uses beamforming for transmission of the data, and the destination utilizes the maximal ratio combining for demodulating the transmitted signal. The uplink and downlink satellite channels are assumed to be shadowed-Rician (SR) fading. First, we consider independent and identically distributed SR fading and derive the closed-form expressions of the approximate bit error rate (BER) and probability of outage for the considered scheme. By using the BER expression, the analytical diversity order of the scheme is obtained. It is deduced on the basis of the diversity order analysis that the diversity of the considered DF scheme linearly depends upon the minimum number of antennas at the source and destination nodes. Next, we consider correlated SR fading links and derive power-series-based expression of the approximate BER of the DF satellite relay system. For the correlated SR fading, the diversity order is analytically obtained; it is shown by analysis and simulation that the diversity order of the scheme with correlated channels does not depend upon the antenna correlation matrices of the source and destination nodes.