In this paper, we investigate the realization of covert communication in a general radar-communication cooperation system, which includes integrated sensing and communications as a special example. We explore the possibility of utilizing the sensing ability of radar to track and jam the aerial adversary target attempting to detect the transmission. Based on the echoes from the target, the extended Kalman filtering technique is employed to predict its trajectory as well as the corresponding channels. Depending on the maneuvering altitude of adversary target, two channel models are considered, with the aim of maximizing the covert transmission rate by jointly designing the radar waveform and communication transmit beamforming vector based on the constructed channels. For the free-space propagation model, by decoupling the joint design, we propose an efficient algorithm to guarantee that the target cannot detect the transmission. For the Rician fading model, since the multi-path components cannot be estimated, a robust joint transmission scheme is proposed based on the property of the Kullback-Leibler divergence. The convergence behaviour, tracking MSE, false alarm and missed detection probabilities, and covert transmission rate are evaluated. Simulation results show that the proposed algorithms achieve accurate tracking. For both channel models, the proposed sensing-assisted covert transmission design is able to guarantee the covertness, and significantly outperforms the conventional schemes.

翻译：本文研究了一般雷达-通信协作系统中隐蔽通信的实现方式，其中将感知与通信一体化作为特例。我们探索利用雷达的感知能力跟踪并干扰试图检测传输信号的空中敌对目标的可能性。基于目标回波，采用扩展卡尔曼滤波技术预测其轨迹及相应信道。根据敌对目标的机动高度，考虑两种信道模型，旨在通过联合设计基于所构建信道的雷达波形和通信发射波束成形向量，最大化隐蔽传输速率。针对自由空间传播模型，通过解耦联合设计，提出一种高效算法以确保目标无法检测到传输。针对莱斯衰落模型，由于多径分量无法估计，基于库尔贝克-莱布勒散度的特性提出一种鲁棒联合传输方案。评估了收敛行为、跟踪均方误差、虚警概率、漏检概率及隐蔽传输速率。仿真结果表明，所提算法能够实现精确跟踪。对于两种信道模型，所提出的感知辅助隐蔽传输设计能够保证隐蔽性，并显著优于传统方案。