We abstract the core logical functions from applications that require ultra-low-latency wireless communications to provide a novel definition for reliability. Real-time applications — such as intelligent transportation, remote surgery, and industrial automation — involve a significant element of control and decision making. Such systems involve three logical components: observers (e.g. sensors) measuring the state of an environment or dynamical system, a centralized executive (e.g. controller) deciding on the state, and agents (e.g. actuators) that implement the executive’s decisions. The executive harvests the observers’ measurements and decides on the short-term trajectory of the system by instructing its agents to take appropriate actions. All observation packets (typically uplink) and action packets (typically downlink) must be delivered by hard deadlines to ensure the proper functioning of the controlled system. In-full on-time delivery cannot be guaranteed in wireless systems due to inherent uncertainties in the channel such as fading and unpredictable interference; accordingly, the executive will have to drop some packets. We develop a novel framework to formulate the Observer Selection Problem (OSP) through which the executive schedules a sequence of observations that maximize its knowledge about the current state of the system. To solve this problem efficiently yet optimally, we devise a branch-and-bound algorithm that systematically prunes the search space. Our work is different from existing work on real-time communications in that communication reliability is not conveyed by packet loss or error rate, but rather by the extent of the executive’s knowledge about the state of the system it controls.

中文翻译：

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在具有硬交付期限的共享通道上调度观察者

我们从需要超低延迟无线通信的应用程序中抽象出核心逻辑功能，以提供新的可靠性定义。实时应用——例如智能交通、远程手术和工业自动化——涉及控制和决策的重要元素。此类系统涉及三个逻辑组件：测量环境或动态系统状态的观察者（例如传感器）、决定状态的中央执行器（例如控制器）和执行执行器决策的代理（例如执行器）。执行部门收集观察者的测量结果，并通过指示其代理采取适当的行动来决定系统的短期轨迹。所有观察数据包（通常是上行链路）和动作数据包（通常是下行链路）必须在硬期限内交付，以确保受控系统的正常运行。由于信道中固有的不确定性，例如衰落和不可预测的干扰，无线系统无法保证完全准时交付；因此，执行程序将不得不丢弃一些数据包。我们开发了一个新颖的框架来制定观察者选择问题 (OSP)，通过该框架，执行人员安排一系列观察，以最大限度地了解系统当前状态。为了有效而优化地解决这个问题，我们设计了一种分支定界算法，系统地修剪搜索空间。