This article considers a wireless networked control system (WNCS) consisting of a dynamic system to be controlled (i.e., a plant), a sensor, an actuator, and a remote controller for mission-critical Industrial Internet of Things (IIoT) applications. A WNCS has two types of wireless transmissions, i.e., the sensor's measurement transmission to the controller and the controller's command transmission to the actuator. In the literature of WNCSs, the controllers are commonly assumed to work in a full-duplex (FD) mode by default, i.e., being able to simultaneously receive the sensor's information and transmit its own command to the actuator. In this article, we consider a practical half-duplex (HD) controller, which introduces a novel transmission-scheduling problem for WNCSs. A frequent scheduling of sensor's transmission results in a better estimation of plant states at the controller and thus a higher quality of control command, but it leads to a less frequent/timely control of the plant. Therefore, considering the overall control performance of the plant in terms of its average cost function, there exists a fundamental tradeoff between the sensor's and the controller's transmissions. We formulate a new problem to optimize the transmission-scheduling policy for minimizing the long-term average cost function. We derive the necessary and sufficient condition of the existence of a stationary and deterministic optimal policy that results in a bounded average cost in terms of the transmission reliabilities of the sensor-to-controller and controller-to-actuator channels. Also, we derive an easy-to-compute suboptimal policy, which notably reduces the average cost of the plant compared to a naive alternative-scheduling policy.

中文翻译：

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工业物联网无线网络控制的最优下行__plink调度


本文考虑了一种无线网络控制系统 (WNCS)，该系统由要控制的动态系统（即工厂）、传感器、执行器和远程控制器组成，用于任务关键型工业物联网 (IIoT) 应用。 WNCS有两种类型的无线传输，即传感器的测量传输到控制器和控制器的命令传输到执行器。在WNCS的文献中，通常假设控制器默认工作在全双工（FD）模式，即能够同时接收传感器的信息并将其自己的命令传输到执行器。在本文中，我们考虑一种实用的半双工 (HD) 控制器，它为 WNCS 引入了一个新颖的传输调度问题。传感器传输的频繁调度可以使控制器更好地估计工厂状态，从而提高控制命令的质量，但会导致工厂控制的频率/及时性降低。因此，考虑到设备的平均成本函数的整体控制性能，传感器和控制器的传输之间存在基本的权衡。我们提出了一个新问题来优化传输调度策略，以最小化长期平均成本函数。我们推导了存在固定且确定性最优策略的充分必要条件，该策略导致传感器到控制器和控制器到执行器通道的传输可靠性方面的平均成本有界。此外，我们得出了一种易于计算的次优策略，与简单的替代调度策略相比，它显着降低了工厂的平均成本。