Cooperative covert communication in multi-antenna broadcast channels

With the gradual popularization of 5G communications, the application of multi-antenna broadcasting technology has become widespread. Therefore, this study aims to investigate the wireless covert communication in the two-user cooperative multi-antenna broadcast channel. We focus on the issue that the deteriorated reliability and undetectability are mainly affected by the transmission power. To tackle this issue, we design a scheme based on beamforming to increase the reliability and undetectability of wireless covert communication in the multi-antenna broadcast channel. We first modeled and analyzed the cooperative multi-antenna broadcasting system, and put forward the target question. Then we use the SCA (successive convex approximation) algorithm to transform the target problem into a series of convex subproblems. Then the convex problems are solved and the covert channel capacity is calculated. In order to verify the effectiveness of the scheme, we conducted simulation verification. The simulation results show that the proposed beamforming scheme can effectively improve the reliability and undetectability of covert communication in multi-antenna broadcast channels.