Adaptive phase configuration of intelligent reflecting surface in secure wireless networks using MOPSO

In this paper, propose a novel scheme to enhance the reliability and security of wireless communications by utilising an intelligent reflecting surface (IRS) with multi objective particle swap optimization (MOPSO) algorithm-optimised sub-wavelength unit cells. The design objectives of our proposed scheme are to enhance the signal-to-noise-ratio (SNR) for legitimate users and limit the SNR for eavesdroppers. A two-dimensional simulation has been carried out, where a 29×20-element IRS is deployed in addition to seven users, which can be quality of service (QOS)-demanding ones. The proposed MOPSO algorithm intelligently adjusts IRS phase shifts to enhance the desired signal link and suppress interference. Simulation results show a performance improvement of up to 37.19 dB for legitimate users, while degrading the eavesdropper's SNR to −12.14 db. The obtained scheme is demonstrated to be noise-tolerant and user mobility resistant, demonstrating its suitability for secure and energy-friendly sixth-generation 6G applications. These results affirm that IRS demands intelligent optimisation, instead of arbitrary settings, to achieve stable communication performance and physical layer security.