Multi-pair two-way massive MIMO AF full-duplex relaying with ZFR/ZFT and imperfect CSI

This paper investigates a multi-pair two-way massive MIMO amplify-and-forward full-duplex relay (MM-AFFDR) system over Ricean fading channels, where multiple pairs of full-duplex users exchange information within pair through a full-duplex relay with very large number of antennas (M for transmission and M for reception). Firstly, the zero-forcing reception/zero-forcing transmission (ZFR/ZFT) processing matrix with imperfect channel state information (CSI) at the relay is presented. Then, the asymptotic expression of the end-to-end SINR is derived. Finally, The asymptotic spectral efficiency and energy efficiency at the general power scaling schemes when the number of the relay antennas tends to infinity are analyzed. Theoretical analyses and simulation results show that, when M → ∞, the effects of channel estimation error and the self-loop of each user as well as the relay can be eliminated if the power scaling scheme is properly selected. Besides, the considered multipair two-way FDR outperforms the multi-pair two-way HDR when M is large.