Designing wireless powered networks assisted by intelligent reflecting surfaces with mechanical tilt

Zoran Hadzi-Velkov, Slavche Pejoski, Nikola Zlatanov, Haris Gacanin

Research output: Contribution to journalArticleResearchpeer-review

Abstract

In this paper, we propose a fairness-aware rate maximization scheme for a wireless powered communications network (WPCN) assisted by an intelligent reflecting surface (IRS). The proposed scheme combines user scheduling based on time division multiple access (TDMA) and (mechanical) angular displacement of the IRS. Each energy harvesting user (EHU) has dedicated time slots with optimized durations for energy harvesting and information transmission whereas, the phase matrix of the IRS is adjusted to focus its beam to a particular EHU. The proposed scheme exploits the fundamental dependence of the IRS channel path-loss on the angle between the IRS and the node’s line-of-sight, which is often overlooked in the literature. Additionally, the network design can be optimized for large number of IRS unit cells, which is not the case with the computationally intensive state-of-the-art schemes. In fact, the EHUs can achieve significant rates at practical distances of several tens of meters to the base station (BS) only if the number of IRS unit cells is at least a few thousand.

Original languageEnglish
Pages (from-to)3355-3359
Number of pages5
JournalIEEE Communications Letters
Volume25
Issue number10
DOIs
Publication statusPublished - Oct 2021

Keywords

  • Antennas
  • Downlink
  • intelligent reflecting surfaces
  • Optimization
  • Radio frequency
  • Resource management
  • System performance
  • Time division multiple access
  • Wireless power transfer

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