Linear Precoder Design for Physical Layer Security via Reconfigurable Intelligent Surfaces

Gayan Amarasuriya, Rafael F. Schaefer, H. Vincent Poor

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

The feasibility of provisioning physical layer security via reconfigurable intelligent surfaces (RISs) is investigated. The key idea is to constructively combine the signals received through the direct and reflected channels at a legitimate user, while degrading the signal quality at a passive eavesdropper by destructive combining of these two signals enabled via a joint effect of intelligent phase control at a large number of passive reflective elements of the RIS and a corresponding precoder design of the base-station. To this end, we advocate adoption of linear precoders, which are designed based on cascaded channels, with sole optimization of phase-shifts at the RIS to maximize the achievable secrecy rate in the presence of a passive eavesdropper. The underlying optimization problem is solved by developing an alternating algorithm to iteratively update the phase-shifts of the RIS. Specifically, the optimal phase-shift design problem can be modeled as a semidefinite program by using relaxation techniques. Thereby, the optimal phase-shift values can be closely approximated by using Gaussian randomization techniques. Our numerical results show that the proposed technique serves as a practical-viable low-complexity alternative to joint optimization of non-linear precoder and RIS phase-shifts.

Original languageEnglish (US)
Title of host publication2020 IEEE 21st International Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728154787
DOIs
StatePublished - May 2020
Event21st IEEE International Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2020 - Atlanta, United States
Duration: May 26 2020May 29 2020

Publication series

NameIEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC
Volume2020-May

Conference

Conference21st IEEE International Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2020
Country/TerritoryUnited States
CityAtlanta
Period5/26/205/29/20

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering
  • Computer Science Applications
  • Information Systems

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