Energy Efficient SWIPT Systems in Multi-Cell MISO Networks

• Published in: IEEE transactions on wireless communications Vol. 17; no. 12; pp. 8180 - 8194
• Main Authors: Jang, Seokju, Lee, Hoon, Kang, Seowoo, Oh, Taeseok, Lee, Inkyu
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-12-2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antennas; Array signal processing; Beamforming; Computer simulation; Decoding; Energy consumption; Energy efficiency; Energy harvesting; Integrated circuit modeling; Interference; MISO (control systems); MISO communication; multi-cell coordination; Power efficiency; Power transfer; Quality of service; simultaneous wireless information and power transfer (SWIPT); Transfer stations; Wireless communication; Wireless networks
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2018.2874646

This paper studies beamforming design problems for multi-cell multi-user downlink networks with simultaneous wireless information and power transfer (SWIPT). In this system, multi-antenna base stations (BSs) concurrently transfer information and energy to multiple single-antenna information decoding (ID) and energy-harvesting (EH) users. We aim to maximize EH efficiency (EHE) that is defined as the ratio of the harvested energy at the EH users to the amount of energy consumption at the BSs while guaranteeing the quality-of-service constraint for each ID user. The EHE metric quantifies the efficiency of the power transfer capability of the SWIPT network. For the EH operation, both an ideal linear model and a practical non-linear model are individually investigated. We optimally solve this non-convex problem in two different scenarios according to the cooperation level among the BSs. First, for the centralized case, where global channel state information (CSI) is available at all BSs, we propose a centralized beamforming method based on the semi-definite relaxation and the successive convex approximation techniques. Next, in order to reduce the backhaul signaling overhead, decentralized algorithms are presented where each BS computes its beamforming vector by only using local CSI. The simulation results show that the proposed SWIPT beamforming algorithms offer a significant EHE performance gain over conventional schemes.