Reconfigurable Intelligent Surface Assisted Multi-User Communications: How Many Reflective Elements Do We Need?

Hongliang Zhang, Boya Di, Zhu Han, H. Vincent Poor, Lingyang Song

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Reconfigurable intelligent surfaces (RISs) consisting of multiple reflective elements are a promising technique to enhance communication quality as they can create favorable propagation conditions. In this letter, we characterize the fundamental relations between the number of reflective elements and the system sum-rate in RIS-assisted multi-user communications. It is known from previous works that the received signal-to-noise ratio (SNR) can linearly increase with the squared number of RIS reflective elements, but how many elements are sufficient to provide an acceptable system sum-rate still remains an open problem. To this end, we derive the asymptotic capacity with zero-forcing (ZF) precoding, and then analyze how many reflective elements are required so that the ratio of the system sum-rate to the capacity can exceed a predefined threshold. Numerical results verify our analysis.

Original languageEnglish (US)
Article number9352958
Pages (from-to)1098-1102
Number of pages5
JournalIEEE Wireless Communications Letters
Volume10
Issue number5
DOIs
StatePublished - May 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering
  • Control and Systems Engineering

Keywords

  • Reconfigurable intelligent surface
  • multi-user communications
  • reflective elements

Fingerprint

Dive into the research topics of 'Reconfigurable Intelligent Surface Assisted Multi-User Communications: How Many Reflective Elements Do We Need?'. Together they form a unique fingerprint.

Cite this