In this work, we consider a covert communication scenario, where a transmitter Alice communicates to a receiver Bob with the aid of a probabilistic and uninformed jammer against an adversary warden's detection. The transmission status and power of the jammer are random and follow some priori probabilities. We first analyze the warden's detection performance as a function of the jammer's transmission probability, transmit power distribution, and Alice's transmit power. We then maximize the covert throughput from Alice to Bob subject to a covertness constraint, by designing the covert communication strategies from three different perspectives: Alice's perspective, the jammer's perspective, and the global perspective. Our analysis reveals that the minimum jamming power should not always be zero in the probabilistic jamming strategy, which is different from that in the continuous jamming strategy presented in the literature. In addition, we prove that the minimum jamming power should be the same as Alice's covert transmit power, depending on the covertness and average jamming power constraints. Furthermore, our results show that the probabilistic jamming can outperform the continuous jamming in terms of achieving a higher covert throughput under the same covertness and average jamming power constraints.

翻译：本文研究一种隐蔽通信场景：发送方Alice在概率性且无信息干扰器的辅助下，向接收方Bob传输信息以对抗敌方监视者Warden的检测。干扰器的传输状态与功率均服从随机分布且遵循先验概率。首先，以干扰器传输概率、发射功率分布及Alice发射功率为函数，分析Warden的检测性能。随后，在隐蔽性约束条件下，从三种不同视角（Alice视角、干扰器视角及全局视角）设计隐蔽通信策略，以最大化Alice至Bob的隐蔽吞吐量。分析表明：概率干扰策略中的最小干扰功率无需始终为零，这与现有文献中连续干扰策略的特性存在差异。此外，本文证明最小干扰功率应等于Alice的隐蔽发射功率，其取值取决于隐蔽性约束与平均干扰功率约束。进一步地，研究结果显示：在相同隐蔽性与平均干扰功率约束下，概率干扰策略相比连续干扰策略能实现更高的隐蔽吞吐量。