Tradeoffs in covert wireless communication with a controllable full-duplex receiver

This paper investigates the tradeoff of the communication link and the eavesdropping link in covert communication in the presence of a full-duplex (FD) receiver. When a warden (Willie) attempts to detect the signal transmitted from a legitimate transmitter (Alice), the controllable FD receiver (Bob) can transmit with random power to impose interference uncertainty to Willie and force it to make an incorrect decision. To maximize the average transmission rate (ATR) of Alice-Bob and the average covert probability (ACP) for Willie, we propose a multi-objective optimization framework to optimize Bob's power uncertainty range (PUR) and spatial position jointly, subject to the sufficient condition for covert communication and the none-deployed-zone (NDZ). Due to the presence of multiple optimization objectives and nonconvex constraints, the nondominated sorting genetic algorithm II (NSGA-II) is utilized to explore the Pareto front and to give a set of solutions that reflect tradeoffs between the two conflicting objectives. Simulation results reveal that the solutions determined by the NSGA-II have larger values for both ATR and ACP than the other two baselines. Simulations also show the positive effect of the width of the PUR of Bob on the Pareto front.