EE Enhancement in FD MIMO Relay System through Adaptive Antenna Allocation and Self-Energy Recycling

In this work, the energy efficiency (EE) of a decode-and-forward (DF) full-duplex (FD) multiple-input multiple-output (MIMO) relay system is investigated, that employs adaptive antenna allocation (AAA) and self-energy recycling (S-ER). The proposed AAA scheme enhances the EE of the FD relay system by allocating antennas, in an adaptive manner, for information transmission and reception while simultaneously facilitating S-ER at the FD relay. Specifically, the proposed scheme presents a distribution of antennas for transmission and reception of information at the FD relay, which enhances the spectral efficiency (SE) and reduces the circuit power consumption, which consequently increases the EE of the FD relay system. Further, the antennas corresponding to lower channel gains are adaptively utilized to harvest the inherently present self-interference (SI) at the relay node, which further boosts the EE. The closed-form expressions for the SE and EE have been derived for the proposed AAA scheme with S-ER. A good agreement between simulation and analytical results validates the proposed analysis.