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在概率性且无先验信息的干扰器辅助下，与接收方Bob进行通信，以对抗敌手监控者Warden的检测。干扰器的传输状态与功率服从随机分布，且遵循某些先验概率。首先，我们分析了Warden的检测性能与干扰器传输概率、发射功率分布及Alice发射功率的依赖关系。随后，在隐蔽性约束条件下，从三个不同视角（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：与文献中连续干扰策略不同，概率性干扰策略的最小干扰功率并非始终为零。此外，我们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，研究结果表明：在相同的隐蔽性与平均干扰功率约束下，概率性干扰相较于连续干扰能实现更高的隐蔽吞吐量。