Two-way Full-duplex Relay Systems Research Articles

Outage Performance Analysis of Multi-User Selection for Two-Way Full-Duplex Relay Systems

In this letter, we consider a multi-user two-way full-duplex (FD) relay system, where the user pairs are predefined and the multiple pairs are competing one relay node to exchange messages within the pair. The system is suffering from independent but not identically distributed fading channels. We analyze the system outage performance with Max–Min scheduling scheme. The exact closed-form outage probability expressions are derived. In addition, the impacts of the residual self-interference incurred by the FD mode are considered. Moreover, we obtain some insights on the self-interference cancellation requirements for the FD mode. The superiority of FD mode and the multi-user diversity gain of the system are verified by the analytical results, which are corroborated by the numerical simulations.

Spectral and Energy Efficiency of Multipair Two-Way Full-Duplex Relay Systems With Massive MIMO

In this paper, we consider a multipair amplify-and-forward two-way relay channel, where multiple pairs of full-duplex users exchange information through a full-duplex relay with massive antennas. For improving the energy efficiency, four typical power-scaling schemes are proposed based on the maximum-ratio combining/maximum-ratio transmission (MRC/MRT) and zero-forcing reception/zero-forcing transmission (ZFR/ZFT) at the relay. When the number of relay antennas tends to infinity, we quantify the asymptotic spectral efficiencies and energy efficiencies for the proposed power-scaling schemes. We show that the loop interference can be reduced by decreasing the transmit power under massive relay antennas. Besides, the inter-pair interference and inter-user interference in such systems can also be eliminated in large number of antennas. Moreover, we analytically compare the performance between MRC/MRT and ZFR/ZFT, and describe the impact of the number of user pairs on the spectral efficiency. We also evaluate the energy efficiency performance based on the practical power consumption model, and depict the impact of the relay antenna number on the energy efficiencies for the proposed schemes. Furthermore, we provide the available regions where full-duplex systems can outperform half-duplex systems. Finally, we show that the proposed schemes achieve good performance tradeoffs between the spectral efficiency and the energy efficiency.