Adaptive Power Control for Cooperative Covert Communications with Imperfect CSI

To address the issue that transmitters in existing decode-and-forward (DF) cooperative covert communications hardly acquire all the required channel state information (CSI), this study proceeds as follows. First, an adaptive power strategy for cooperative covert communications based on partial CSI is proposed. Second, the closed-form analytical expression of the covert constraint is derived using the Kullback–Leibler (KL) divergence. Finally, an optimization problem is formulated with the objective of maximizing the covert transmission rate, and the optimal selection of power control parameters is derived. The numerical results demonstrate that in cooperative covert communications, the adaptive power strategy significantly enhances the system’s covert transmission rate compared to the constant power strategy, particularly under relaxed covert constraints. Meanwhile, the proposed strategy also markedly reduces the transmission outage probability. Overall comparative analysis confirms that the adaptive power strategy effectively improves the comprehensive covert performance of the system.