Joint Optimization for Anti-jamming Communication with UAV-carried Intelligent Reflecting Surface

Wireless communications involving unmanned aerial vehicles (UAVs) are more vulnerable to the malicious jamming. As a promising solution, intelligent reflecting surface (IRS) can be equipped on the UAVs to achieve anti-jamming transmissions by leveraging the reconfigurable passive beamforming technique. In this paper, we study a wireless communication system where a UAV carries an IRS and acts as a mobile relay for a multi-antenna transmitter and receiver pair in the presence of a smart jammer that transmits jamming signals to the receiver and the IRS simultaneously. By jointly designing the transmit beamformer, IRS reflection phase, and UAV trajectory, we aim to maximize the average achievable rate over the entire flight with effective resistance to jamming attacks. To solve the non-convex problem, we adopt the alternating optimization (AO) algorithm and decompose the problem into two subproblems, i.e., joint optimization of the transmit beamformer and reflection phase for a specific time slot and optimization of the UAV trajectory. Simulation results show that the proposed joint optimization framework can well combat the jammer under various network settings such as changing the position of the jammer and the initial position of the UAV. The proposed algorithm has good convergence and achieves better performance than other benchmark schemes.