Intelligent Omni-Surfaces for Simultaneous Beamforming and Anti-Jamming

Abstract

Due to the openness of wireless channels, wireless transmission is susceptible to malicious jamming attacks, posing a severe threat to wireless communications. Existing studies on anti-jamming mainly considered enhancing desired signals or mitigating jamming, leading to limited performance. To address this issue, intelligent omni-surface (IOS) is a promising solution, which can simultaneously nullify jamming and enhance desired signals by jointly manipulating its reflective and refractive properties. In this paper, we consider an IOS-aided multi-user anti-jamming communication system. We aim to improve desired signals and nullify jamming by joint IOS phase shifts and transmit beamforming optimization, which is challenging due to the coupled and discrete nature of IOS reflection and refraction phase shifts, unknown jammer’s beamformer, and imperfect jammer-related channel state information. To tackle this, we relax IOS phase shifts to continuous states and develop a coupling-aware algorithm using Cauchy-Schwarz inequality and S-procedure, followed by a local search to recover discrete states. Simulation results show that the proposed scheme significantly improves the sum rate in the presence of jamming attacks.