Outage performance for full-duplex relaying satellite-terrestrial multi-antenna NOMA systems with imperfect SIC

Due to the masking effect, a reliable line-of-sight transmission between a satellite and terrestrial nodes is not always guaranteed, and a half-duplex (HD) relaying is commonly performed in literature to assist such transmission. However, the system efficiency could be seriously degraded with the HD relaying as a two-time slot is required for a dual-hop information transmission. Therefore, in this paper, a full-duplex (FD) relaying, which can enable signal receiving and transmitting simultaneously, is considered for a satellite-terrestrial non-orthogonal multiple access (NOMA) system consisting of a multi-antenna satellite source, a FD relay, and two multi-antenna destination nodes. Specifically, the satellite source adopts a maximum ratio transmission scheme to transmit a NOMA signal to the relay, and the relay deploys a decode-and-forward protocol to forward the information to two destination nodes simultaneously, which employ the maximal ratio combining strategy to process the received signals. Assuming the satellite link experiences Shadowed-Rician fading and the terrestrial links undergo Nakagami-m fading distribution, both analytical and asymptotic expressions of outage probability (OP) for two destination nodes are presented in the presence of residual self-interference and imperfect successive interference cancellation. In addition, an adaptive power allocation (APA) scheme is performed, and the system throughput under the delay-limited transmission mode is also analyzed. Finally, Monte-Carlo simulations are adopted to verify the accuracy of those derived analytical expressions. Numerical results show that the OP performance with the FD mode outperforms that with the HD one, and adopting the APA scheme can result in the best OP performance.