Wirelessly-Powered Full-Duplex AF MIMO Relay Systems Based on Antenna Switching

• Published in: IEEE communications letters 2019-09, Vol.23 (9), p.1640-1643
• Main Authors: Li, Chuanping, Wen, Wenkun, Wu, Peiran, Xia, Minghua
• Format: Article
• Language: English
• Subjects: Algorithms; Amplify-and-forward relaying; antenna switching; Antennas; Array signal processing; Beamforming; Computer simulation; Energy harvesting; energy recycling; Energy transmission; full-duplex; Greedy algorithms; Iterative algorithms; MIMO (control systems); Optimization; Power efficiency; Power management; Protocols; Relay systems; Relaying; Relays; Resource management; spectral efficiency; Switches; Switching theory; Transmitting antennas
• ISSN: 1089-7798; 1558-2558
• DOI: 10.1109/LCOMM.2019.2924219

This letter proposes a novel wirelessly-powered full-duplex amplify-and-forward (AF) relaying scheme, where the multi-antenna relay can harvest energy from the source and recycle energy from itself by using antenna switching protocol. Unlike conventional fixed antennas relay that can only harvest and recycle energy at the second transmission phase, in the proposed scheme, the relay can also harvest energy at the first transmission phase with dynamic antenna combination. To maximize the spectral efficiency of the system, the transmit power of the source, the beamforming matrix at the relay and its antenna allocation are jointly optimized. Also, to tackle the discontinuity and nonconvexity of the optimization problem, a semi-analytical iterative algorithm is developed. In particular, for a fixed antenna combination at the relay, a closed-form solution to the source power allocation and the beamforming matrix at the relay are derived. Then, a greedy antenna switching algorithm is designed to obtain the best antenna combination. Simulation results demonstrate the near optimality of the proposed algorithm and the superiority of the proposed scheme.