System-level Security Solution for Heterogeneous D2D-underlaid Cellular Network

This paper focuses on the problem of secure communications in a D2D-underlaid cellular network, where device-to-device (D2D) communication operates in a hybrid manner using both millimeter-wave (mmWave) and microwave frequency bands. To combat vigilant adversaries, we employ the technique of covert communication to conceal the presence of legitimate D2D transmissions. The D2D transmitters employ power control, communication-mode switching, and leverage the cellular signals to evade detection by adversaries. The conflict situation between the D2D transmitters and the adversaries is modeled as a Stackelberg game. To mathematically characterize the network's spatial configuration, we utilize the stochastic geometry modeling and consider a large-scale D2D-underlaid network, enabling a system-level analysis of communication strategies. We analyze the game equilibrium and thereafter search for equilibrium by using a bi-level algorithm. Insightful findings are drawn from numerical simulation results.