University of Oulu

K. Nguyen, Q. Vu, L. Tran and M. Juntti, "Energy Efficiency Fairness for Multi-Pair Wireless-Powered Relaying Systems," in IEEE Journal on Selected Areas in Communications, vol. 37, no. 2, pp. 357-373, Feb. 2019. doi: 10.1109/JSAC.2018.2872377

Energy efficiency fairness for multi-pair wireless-powered relaying systems

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Author: Nguyen, Kien-Giang1; Vu, Quang-Doanh1; Tran, Le-Nam2;
Organizations: 1Centre for Wireless Communications, University of Oulu, FI-90014 Oulu, Finland
2School of Electrical and Electronic Engineering, University College Dublin, Belfield, Dublin 4, Ireland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 0.5 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2019
Publish Date: 2019-04-16


We consider a multi-pair amplify-and-forward relay network where the energy-constrained relays adopting the time-switching protocol harvest energy from the radio-frequency signals transmitted by the users for assisting user data transmission. Both one-way and two-way relaying techniques are investigated. Aiming at energy efficiency (EE) fairness among the user pairs, we construct an energy consumption model incorporating rate-dependent signal processing power, the dependence on output power level of power amplifiers’ efficiency, and nonlinear energy harvesting (EH) circuits. Then, we formulate the max-min EE fairness problems in which the data rates, users’ transmit power, relays’ processing coefficient, and EH time are jointly optimized under the constraints on the quality of service and users’ maximum transmit power. To achieve efficient suboptimal solutions to these nonconvex problems, we devise monotonic descent algorithms based on the inner approximation (IA) framework, which solve a second-order-cone program in each iteration. To further simplify the designs, we propose an approach combining IA and zero-forcing beamforming, which eliminates inter-pair interference and reduces the numbers of variables and required iterations. Finally, extensive numerical results are presented to validate the proposed approaches. More specifically, the results demonstrate that ignoring the realistic aspects of power consumption might degrade the performance remarkably, and jointly designing parameters involved could significantly enhance the EE.

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Series: IEEE journal on selected areas in communications
ISSN: 0733-8716
ISSN-E: 1558-0008
ISSN-L: 0733-8716
Volume: 37
Issue: 2
Pages: 357 - 373
DOI: 10.1109/JSAC.2018.2872377
Type of Publication: A1 Journal article – refereed
Field of Science: 113 Computer and information sciences
213 Electronic, automation and communications engineering, electronics
Funding: This work was supported in part by the Academy of Finland under the projects “Wireless Connectivity for Internet of Everything–Energy Efficient Transceiver and System Design” under Grant 297803, “Flexible Uplink-Downlink Resource Management for Energy and Spectral Efficiency Enhancing in Future Wireless Networks” under Grant 310898, and “6Genesis Flagship” under Grant 318927. This publication has also emanated from research supported in part by a Grant from Science Foundation Ireland under Grant 17/CDA/4786. The work of K.-G. Nguyen was supported in part by the HPY Research Foundation, in part by the Nokia Foundation, in part by the Walter Ahlström Foundation, in part by the Finnish Foundation for Technology Promotion, and in part by the Tauno Tönning Foundation.
Academy of Finland Grant Number: 297803
Detailed Information: 297803 (Academy of Finland Funding decision)
310898 (Academy of Finland Funding decision)
318927 (Academy of Finland Funding decision)
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