Design of IRS-assisted SWIPT System based on Direction Modulation

This paper first proposes an innovative design methodology for an intelligent reflecting surface (IRS)-assisted simultaneous wireless information and power transfer (SWIPT) system, which leverages directional modulation (DM) to achieve joint optimization of information security transmission and efficient energy harvesting through physical layer security enhancement techniques. The proposed approach guarantees that the excited on weight coefficients at the base station transmitter, the discrete phase shift matrix of the IRS, and the power allocation ratio at the receiver are jointly optimized. While guaranteeing the accurate decoding of information and the energy harvesting threshold for legitimate users, it minimizes the mismatch between the desired null response and the actual beam response towards eavesdroppers, effectively suppressing the risk of information leakage. This approach effectively mitigates information leakage risks and significantly enhances system security. In response to the actual deployment requirements, a discrete phase shift optimization strategy is proposed to reduce hardware costs. Simulation results indicate that the proposed design can make the signal amplitude in the direction of the eavesdropper weaker and the phase randomly scrambled, enhancing the security and reliability of the system. Furthermore, the algorithm convergence shows that the cost function optimization stabilizes after iterations, highlighting the system's practicability. This study offers a low-cost and high-security physical layer transmission framework for IRS-assisted SWIPT systems.