Secrecy Rate Analysis of STAR-RIS in Presence of Energy Harvesting Eavesdroppers

TL;DR

This paper analyzes the secrecy rate and energy harvesting capabilities of a STAR-RIS wireless system with untrusted energy harvesting eavesdroppers, optimizing transmission and reflection coefficients to enhance security and energy efficiency.

Contribution

It introduces a novel optimization framework for maximizing secrecy rate in STAR-RIS systems with energy harvesting eavesdroppers, using advanced convex optimization techniques.

Findings

Secrecy rate increases with STAR-RIS size.

Optimized TARCs improve secrecy and energy harvesting trade-offs.

Numerical results demonstrate the effectiveness of the proposed optimization.

Abstract

This work peruses a simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) based wireless system wherein untrusted energy harvesting nodes wiretap the legitimate signal. The achievable secrecy rate and the harvested energy for multicast communication are computed as functions of STAR-RIS transmission and reflection coefficients (TARCs). Thus, to maximize the secrecy rate while satisfying the minimum required harvested energies, the non-convex optimization problem is investigated. By using the Dinkelbach transformation and semi-definite relaxation technique, the optimization problem is transformed into a convex problem. Eventually, the numerical results are reported to specify the effects of the size of the STAR-RIS and optimizing its TARCs elements on magnifying the secrecy rate-energy harvesting region.