Outage Analysis and Finite SNR Diversity-Multiplexing Tradeoff of Hybrid-Duplex Systems for Aeronautical Communications

A hybrid-duplex aeronautical communication system (HBD-ACS) consisting of a full-duplex-enabled ground station (GS) and two half-duplex (HD) air stations (ASs) is proposed as a direct solution to the spectrum crunch faced by the aviation industry. The closed-form outage probability and finite signal-to-noise ratio (SNR) diversity gain expressions in aeronautical communications over Rician fading channels are derived for a successive interference cancellation (SIC) detector. Similar expressions are also presented for an interference ignorant (II) detector and the HD-equivalent modes at GS and ASs. Through the outage and finite SNR diversity gain analysis conducted at the nodes, and system level, residual self-interference (SI) and inter-AS interference are found to be the primary limiting factors in the proposed HBD-ACS. Further investigations revealed that the II and SIC detectors in the proposed HBD-ACS are suitable for the weak and strong interference scenarios, respectively. When compared with the HD-ACS, the proposed HBD-ACS achieves a lower outage probability and higher diversity gains at higher multiplexing gains when operating at low SNRs. The finite SNR analysis also showed the possibility of the proposed HBD-ACS being able to attain interference-free diversity gains through proper management of the residual SI. Hence, the proposed HBD-ACS is more reliable and can provide a better throughput compared with the existing HD-ACS at low-to-moderate SNRs.