Recent works have considered the ability of transmitter Alice to communicate reliably to receiver Bob without being detected by warden Willie. These works generally assume a standard discrete-time model. But the assumption of a discrete-time model in standard communication scenarios is often predicated on its equivalence to a continuous-time model, which has not been established for the covert communications problem. Here, we consider the continuous-time channel directly and study if efficient covert communication can still be achieved. We assume that an uninformed jammer is present to assist Alice, and we consider additive white Gaussian noise (AWGN) channels between all parties. For a channel with approximate bandwidth W, we establish constructions such that O(WT) information bits can be transmitted covertly and reliably from Alice to Bob in T seconds for two separate scenarios: 1) when the path-loss between Alice and Willie is known; and 2) when the path-loss between Alice and Willie is unknown.

中文翻译：

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连续时间系统中的隐蔽通信

最近的工作考虑了发射器 Alice 与接收器 Bob 进行可靠通信而不会被看守威利检测到的能力。这些工作通常假设一个标准的离散时间模型。但是，标准通信场景中离散时间模型的假设通常基于它与连续时间模型的等价性，而连续时间模型尚未针对隐蔽通信问题建立。在这里，我们直接考虑连续时间信道并研究是否仍然可以实现有效的隐蔽通信。我们假设存在一个不知情的干扰机来协助 Alice，我们考虑所有各方之间的加性高斯白噪声 (AWGN) 信道。对于具有近似带宽 W 的信道，我们建立了这样的结构，使得 O(WT) 信息位可以在 T 秒内从 Alice 秘密可靠地传输到 Bob，适用于两种不同的情况：1）当 Alice 和 Willie 之间的路径损耗已知时；2) 当 Alice 和 Willie 之间的路径损耗未知时。