University of Oulu

O. L. A. López, D. Kumar, R. D. Souza, P. Popovski, A. Tölli and M. Latva-Aho, "Massive MIMO With Radio Stripes for Indoor Wireless Energy Transfer," in IEEE Transactions on Wireless Communications, vol. 21, no. 9, pp. 7088-7104, Sept. 2022, doi: 10.1109/TWC.2022.3154428

Massive MIMO with radio stripes for indoor wireless energy transfer

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Author: López, Onel L. A.1; Kumar, Dileep1; Souza, Richard Demo2;
Organizations: 1Centre for Wireless Communications, University of Oulu, 90570 Oulu, Finland
2Department of Electrical and Electronics Engineering, Federal University of Santa Catarina (UFSC), Florianópolis 88040-900, Brazil
3Department of Electronic Systems, Aalborg University, 9220 Aalborg, Denmark
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.2 MB)
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Language: English
Published: Institute of Electrical and Electronics Engineers, 2022
Publish Date: 2022-09-22


Radio frequency wireless energy transfer (WET) is a promising solution for powering autonomous Internet of Things (IoT) deployments. In this work, we leverage energy beamforming for powering multiple user equipments (UEs) with stringent energy harvesting (EH) demands in an indoor distributed massive multiple-input multiple-output system. Based on semi-definite programming, successive convex approximation (SCA), and maximum ratio transmission (MRT) techniques, we derive optimal and sub-optimal precoders aimed at minimizing the radio stripes’ transmit power while exploiting information of the power transfer efficiency of the EH circuits at the UEs. Moreover, we propose an analytical framework to assess and control the electromagnetic field (EMF) radiation exposure in the considered indoor scenario. Numerical results show that i) the EMF radiation exposure can be more easily controlled at higher frequencies at the cost of a higher transmit power consumption, ii) training is not a very critical factor for the considered indoor system, iii) MRT/SCA-based precoders are particularly appealing when serving a small number of UEs, thus, especially suitable for implementation in a time domain multiple access (TDMA) scheduling framework, and iv) TDMA is more efficient than spatial domain multiple access (SDMA) when serving a relatively small number of UEs. Results suggest that additional boosting performance strategies are needed to increase the overall system efficiency, thus making the technology viable in practice.

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Series: IEEE transactions on wireless communications
ISSN: 1536-1276
ISSN-E: 1558-2248
ISSN-L: 1536-1276
Volume: 21
Issue: 9
Pages: 7088 - 7104
DOI: 10.1109/twc.2022.3154428
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: This work was supported in part by the Academy of Finland—AKA (6Genesis Flagship) under Grant 307492, Grant 319059, and Grant 318927; in part by the National Council of Scientific and Technological Development (CNPq); in part by the Print Coordination for the Improvement of Higher Education Personnel-Federal University of Santa Catarina (CAPES-UFSC) “Automation 4.0;” and in part by the National Education and Research Network/Ministry of Science, Technology and Innovation (RNP/MCTI) 6G Mobile Communications Systems under Grant 01245.010604/2020-14. The work of Petar Popovski was supported in part by the European Union (EU) H2020 RISE-6G Project.
Academy of Finland Grant Number: 307492
Detailed Information: 307492 (Academy of Finland Funding decision)
319059 (Academy of Finland Funding decision)
318927 (Academy of Finland Funding decision)
Copyright information: © The Author(s) 2022. This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see