Self-Sustainable Active Reconfigurable Intelligent Surfaces for Antijamming in Wireless Communications

Wireless devices can be easily attacked by jammers during transmission, which is a potential security threat for wireless communications. Active reconfigurable intelligent surface (RIS) attracts considerable attention and is expected to be employed in antijamming systems for secure transmission to significantly enhance the antijamming performance. However, active RIS introduces external power load, which increases the complexity of hardware and restricts the flexible deployment of active RIS. To overcome these drawbacks, we design an innovative self-sustainable structure in this article, where the active RIS is energized by harvesting energy from base station signals through the time dividing based simultaneous wireless information and power transfer scheme. Based on the above structure, we develop the BS harvesting scheme based on joint transmit and reflecting beamforming with the aim of maximizing the achievable rate of active RIS-assisted system, where the alternating optimization algorithm based on stochastic successive convex approximation tackles the nonconvex optimization problem in the scheme. Simulation results verified the effectiveness of our developed BS harvesting scheme, which can attain higher antijamming performance than other schemes when given the same maximum transmit power.