Selective PNC in satellite-terrestrial network over non-identical fading channels

We analyze the performance of a twoway satellite-terrestrial decode-and-forward (DF) relay network over non-identical fading channels. In particular, selective physical-layer network coding (SPNC) is employed in the proposed network to improve the average end-to-end throughput performance. More specifically, by assuming that the DF relay performs instantaneous throughput comparisons before performing corresponding protocols, we derive the expressions of system instantaneous bit-error-rate (BER), instantaneous end-to-end throughput, average end-to-end throughput, single node detection (SND) occurrence probability and average end-to-end BER over non-identical fading channels. Finally, theoretical analyses and Monte Carlo simulation results are presented. Evaluations show that: 1) SPNC protocol outperforms the conventional physical-layer network coding (PNC) protocol in infrequent light shadowing (ILS), average shadowing (AS) and frequent heavy shadowing (FHS) Shadowed-Rician fading channels. 2) As the satellite-relay channel fading gets more severe, SPNC protocol can achieve more performance improvement than PNC protocol and the occurrence probability of SND protocol increases progressively. 3) The occurrence probability increase of SND has a beneficial effect on the average end-to-end throughput in low signal-to-noise ratio (SNR) regime, while the occurrence probability decrease of SND has a beneficial effect on the average end-to-end BER in high-SNR regime.