Multipair Massive MIMO Relay with Simultaneous Wireless Information and Power Transfer

초록

Considering a decode-and-forward relay network with multiple source-destination pairs, this paper proposes a two-phase relaying protocol, which enables the massive multipleinput multiple-output (MIMO) relay to simultaneously harvest wireless energy from multiple sources’ information signals and multiple destinations’ energy flows (EFs). Asymptotic expression of the harvested energy is derived when a power splitting relay node employs an unlimited number of antennas. The analysis reveals that the asymptotic harvested energy is independent of the fast fading effect of the wireless channel, meanwhile the transmit powers of each source and each destination can be scaled down inversely proportional to the number of relay antennas. To significantly reduce the energy leakage interference (ELI) and multipair interference (MI), the maximum-ratio combing/maximum-ratio transmission (MRC/MRT) techniques have been employed at the relay node. The exact achievable sum rate and the optimal destination transmit power that maximizes the achievable sum rate are derived in closed-form, respectively. Moreover, the fundamental trade-off between the harvested energy and the achievable sum rate is quantified. It has shown that the destination-aided EFs are beneficial for both the energy harvesting at the relay and the quality improvement of the second-hop link. Meanwhile, the detrimental impact of ELI and MI for signal decoding can be cancelled completely by using MRC/MRT when the number of relay antennas grows without bound.