Wireless secure transmission method based on random frequency array and intelligent reflecting surface

The invention relates to a wireless secure transmission method based on a random frequency array and an intelligent reflecting surface, and provides a multi-user system which comprises a transmitting end antenna, an intelligent reflecting surface controller and an intelligent reflecting surface which are connected in sequence, and specifically comprises the following steps: constructing a multi-user system model, selecting the maximum signal to leakage and noise ratio weighted sum of all expected users in the system as a target function of the system; by combining a corresponding convex optimization theory and applying an idea of alternate iterative optimization, a corresponding active beamforming vector and a passive beamforming matrix are obtained, i.e., a reflection matrix of the intelligent reflecting surface is obtained. Based on the random frequency array and the intelligent reflecting surface, safe transmission of a multi-user system can be achieved, and it is guaranteed that a private signal reaches t