Multi-Antenna Covert Communications in Random Wireless Networks.

This paper studies multi-antenna covert communications coexisting with randomly located wardens and interferers. We analyze and optimize the covert throughput under a stochastic geometry framework. We first introduce covert outage probability and connectivity probability to respectively characterize covertness and reliability, and derive analytically tractable expressions for them. We then consider a worst-case covert communication, where the wardens can invariably maximize the covert outage probability by adjusting the detection thresholds of their detectors. Afterwards, we jointly design the optimal transmit power and transmission rate to maximize the covert throughput while satisfying the covertness requirement. Interestingly, it is found that the maximal covert throughput is invariant to either the density of interferers or the interfering power, regardless of the number of transmit antennas.