PhysFad: Physics-Based End-to-End Channel Modeling of RIS-Parametrized Environments with Adjustable Fading

Rashid Faqiri, Chloe Saigre-Tardif, George C. Alexandropoulos, Nir Shlezinger, Mohammadreza F. Imani, Philipp Del Hougne

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Programmable radio environments parametrized by reconfigurable intelligent surfaces (RISs) are emerging as a new wireless communications paradigm, but currently used channel models for the design and analysis of signal-processing algorithms cannot include fading in a manner that is faithful to the underlying wave physics. To overcome this roadblock, we introduce a physics-based end-to-end model of RIS-parametrized wireless channels with adjustable fading (coined PhysFad) which is based on a first-principles coupled-dipole formalism. PhysFad naturally incorporates the notions of space and causality, dispersion (i.e., frequency selectivity) and the intertwinement of each RIS element's phase and amplitude response, as well as any arising mutual coupling effects including long-range mesoscopic correlations. The latter are induced by reverberation and yield a highly nonlinear parametrization of wireless channels through RISs, a pivotal property which is to date completely overlooked. PhysFad offers the to-date missing tuning knob for physics-compliant adjustable fading. We thoroughly characterize PhysFad and demonstrate its capabilities for a prototypical problem of RIS-enabled over-the-air channel equalization in rich-scattering wireless communications. We also share a user-friendly version of our code to help the community transition towards physics-based models with adjustable fading.

Original languageEnglish (US)
Pages (from-to)580-595
Number of pages16
JournalIEEE Transactions on Wireless Communications
Volume22
Issue number1
DOIs
StatePublished - Jan 1 2023

Keywords

  • Reconfigurable intelligent surfaces
  • discrete dipole approximation
  • end-to-end channel modeling
  • fading channels
  • over-the-air equalization

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics

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