Optimizing Age of Information for Multi-Antenna Aided Covert Communications

The performance of wireless communication systems has been improved with the recent advances in array antenna technology. In this paper, we propose a scheme to improve the age of information (AoI) for covert communication with multi-antenna technique (MAT). Specifically, we first propose the transmitter structures and the corresponding beamforming methods for the considered model. Subsequently, the closed-form expressions of the Kullback-Leibler (KL) divergence is derived to serve as the quantitative measure of communication covertness under both schemes, based on which the average covert AoI (CAoI) is derived to jointly characterize the covertness and timeliness performance. Then, to minimize the average CAoI, the optimization problems of the blocklength and beamforming parameters are formulated and solved. Finally, the numerical results are provided to show that the proposed scheme indeed improve the covert communication performance in terms of the average CAoI.