RIS-assisted Physical Layer Security
Xudong Li, Matthias Frey, Ehsan Tohidi, Igor Bjelaković, Sławomir Stańczak
TL;DR
This work develops a RIS-assisted wiretap channel with spatial separation and semantic security (SSOC). It introduces a vector-valued model and derives an achievable secrecy rate under semantic security, then designs a power-allocation MM algorithm to maximize the secrecy rate between direct and RIS-assisted links under a total power constraint. The analysis leverages channel resolvability tools and a distinction-based security metric, establishing conditions for reliable and semantically secure communication in RIS-enabled environments. Simulations show significant secrecy-rate gains from RIS deployment, especially as the eavesdroppers’ locations and numbers vary, highlighting practical security improvements in programmable wireless environments.
Abstract
We propose a reconfigurable intelligent surface (RIS)-assisted wiretap channel, where the RIS is strategically deployed to provide a spatial separation to the transmitter, and orthogonal combiners are employed at the legitimate receiver to extract the data streams from the direct and RIS-assisted links. Then we derive the achievable secrecy rate under semantic security for the RIS-assisted channel and design an algorithm for the secrecy rate optimization problem. The simulation results show the effects of total transmit power, the location and number of eavesdroppers on the security performance.