Covert Communication in Intelligent Reflecting Surface Assisted Networks With a Friendly Jammer

In this paper, we investigate covert communication in intelligent reflecting surface (IRS) assisted networks with a friendly jammer where the jammer radiates random power jamming signals to confuse Willie in detecting the existence of the communication between Alice and Bob. We propose a novel technique that jointly optimizes the transmission probability, transmit power at Alice, IRS reflection matrix, and the interval of jamming power with the aim of maximizing the expected achievable rate at Bob while maintaining the covertness of the communication. In addition, we analyze the impact of the number of IRS elements on the detection error probability (DEP) at Willie and study the trade-off between the number of IRS elements and the covertness of the communication. We show through numerical simulations that the developed technique achieves near-optimal performance with low computational complexity and the analysis on the DEP at Willie is accurate.