In this paper, we establish a framework for low probability of detection (LPD) communication from a sequential change-point detection (SCPD) perspective, where a transmitter, Alice, wants to hide her transmission to a receiver, Bob, from an adversary, Willie. The new framework facilitates modeling LPD communication and further evaluating its performance under the condition that Willie has no prior knowledge about when the transmission from Alice might start and that Willie wants to determine the existence of the communication as quickly as possible in a real-time manner. We consider three different sequential tests, i.e., the Shewhart, the cumulative sum (CUSUM), and the Shiryaev-Roberts (SR) tests, to model Willie’s detection process. Communication is said to be covert if it ceases before being detected by Willie with high probability. Covert probability defined as the probability that Willie is not alerted during Alice’s transmission is investigated. We formulate an optimization problem aiming at finding the transmit power and transmission duration so as to maximize the total amount of information that can be transmitted subject to a high covert probability. Under the Shewhart test, closed-form approximations of the optimal solutions are derived, which will approximate the solutions obtained from exhaustive search. As for the CUSUM and SR tests, we provide effective algorithms to search for the optimal solutions. Numeric results are presented to show the performance of LPD communication.

中文翻译：

---

LPD 通信：顺序变化点检测视角

在本文中，我们从顺序变化点检测 (SCPD) 的角度建立了一个低检测概率 (LPD) 通信框架，其中发射机 Alice 想要向对手隐藏她向接收机 Bob 的传输，威利。新框架有助于建模 LPD 通信并进一步评估其性能，前提是 Willie 没有关于 Alice 的传输何时开始的先验知识，并且 Willie 希望以实时方式尽快确定通信的存在. 我们考虑三种不同的顺序测试，即 Shewhart、累积总和 (CUSUM) 和 Shiryaev-Roberts (SR) 测试，以模拟 Willie 的检测过程。如果在威利很有可能发现之前就停止了通信，则称通信是隐蔽的。隐蔽概率被定义为在 Alice 的传输过程中 Willie 没有被警告的概率。我们制定了一个优化问题，旨在找到发射功率和传输持续时间，以便在高隐蔽概率下最大化可以传输的信息总量。在休哈特检验下，可以导出最优解的封闭形式近似值，这将近似于从穷举搜索中获得的解。对于 CUSUM 和 SR 测试，我们提供了有效的算法来搜索最优解。数值结果显示了 LPD 通信的性能。我们制定了一个优化问题，旨在找到发射功率和传输持续时间，以便在高隐蔽概率下最大化可以传输的信息总量。在休哈特检验下，可以导出最优解的封闭形式近似值，这将近似于从穷举搜索中获得的解。对于 CUSUM 和 SR 测试，我们提供了有效的算法来搜索最优解。数值结果显示了 LPD 通信的性能。我们制定了一个优化问题，旨在找到发射功率和传输持续时间，以便在高隐蔽概率下最大化可以传输的信息总量。在休哈特检验下，可以导出最优解的封闭形式近似值，这将近似于从穷举搜索中获得的解。对于 CUSUM 和 SR 测试，我们提供了有效的算法来搜索最优解。数值结果显示了 LPD 通信的性能。对于 CUSUM 和 SR 测试，我们提供了有效的算法来搜索最优解。数值结果显示了 LPD 通信的性能。对于 CUSUM 和 SR 测试，我们提供了有效的算法来搜索最优解。数值结果显示了 LPD 通信的性能。