Beamforming for MISO Interference Channels with QoS and RF Energy Transfer

• Published in: IEEE transactions on wireless communications Vol. 13; no. 5; pp. 2646 - 2658
• Main Authors: Timotheou, Stelios, Krikidis, Ioannis, Gan Zheng, Ottersten, Bjorn
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Array signal processing; Beamforming; Channels; Coding, codes; Decoding; Detection, estimation, filtering, equalization, prediction; Energy exchange; Exact sciences and technology; Exact solutions; Information, signal and communications theory; Interference; MISO channel; Operation, maintenance, reliability; Optimization; Optimization algorithms; power splitting; Quality of service; Radio frequency; Radio-frequency energy transfer; Receivers; second-order cone programming; Signal and communications theory; Signal, noise; Splitting; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); second-order cone programming; Multiple access; Second order; Transmitter; Radio-frequency energy transfer; Secondary cell; Decoding; Radiofrequency; Algorithm; Power allocation; Beam forming; Optimization; Relaxation; Linear combination; Optimal solution; Signal processing; power splitting; Transmission rate; MISO system; beamforming; Service quality; Energy transfer; MISO channel
• ISSN: 1536-1276; 1558-2248; 1558-2248
• DOI: 10.1109/TWC.2014.032514.131199

We consider a multiuser multiple-input single-output interference channel where the receivers are characterized by both quality-of-service (QoS) and radio-frequency (RF) energy harvesting (EH) constraints. We consider the power splitting RF-EH technique where each receiver divides the received signal into two parts a) for information decoding and b) for battery charging. The minimum required power that supports both the QoS and the RF-EH constraints is formulated as an optimization problem that incorporates the transmitted power and the beamforming design at each transmitter as well as the power splitting ratio at each receiver. We consider both the cases of fixed beamforming and when the beamforming design is incorporated into the optimization problem. For fixed beamforming we study three standard beamforming schemes, the zero-forcing (ZF), the regularized zero-forcing (RZF) and the maximum ratio transmission (MRT); a hybrid scheme, MRT-ZF, comprised of a linear combination of MRT and ZF beamforming is also examined. The optimal solution for ZF beamforming is derived in closed-form, while optimization algorithms based on second-order cone programming are developed for MRT, RZF and MRT-ZF beamforming to solve the problem. In addition, the joint-optimization of beamforming and power allocation is studied using semidefinite programming (SDP) with the aid of rank relaxation.