Massive MIMO full-duplex relaying with hardware impairments

Massive multiple-input-multiple-output full-duplex relaying (MM-FDR), which exploits both the benefits of large-scale antenna arrays and full-duplex transmission, is considered as a promising technology to achieve very high spectral efficiency in the future wireless network. Despite the inevitable presence of transceiver impairments due to the use of low-cost hardware components, most of the prior works on MM-FDR assume perfect transceiver hardware which is unrealistic in practice. This paper investigates the impact of hardware impairments on the MM-FDR. Based on the recent experimental results, the effect of hardware impairments is modeled using transmit and receive distortion noises. The end-to-end achievable rate is derived and the scaling behaviors of echo interference due to the full-duplex operation, multi-user interference and effective distortions caused by hardware impairments are obtained. The scaling results show that the achievable rate of MM-FDR is limited by the hardware impairments at the sources and destinations, instead of that at the relay or other interferences, as the number of relay antenna tends to infinity. A low-complexity power control scheme is proposed to further improve the energy efficiency of MM-FDR with hardware impairments. Simulation results show that the proposed scheme can improve the spectral-energy efficiency tradeoff significantly.