Integrated Communication and Control Systems: A Data Significance Perspective

The interconnected smart devices and industrial internet of things devices require low-latency communication to fulfill control objectives despite limited resources. In essence, such devices have a time-critical nature but also require a highly accurate data input based on its significance. In this paper, we investigate various coordinated and distributed semantic scheduling schemes with a data significance perspective. In particular, novel algorithms are proposed to analyze the benefit of such schemes for the significance in terms of estimation accuracy. Then, we derive the bounds of the achievable estimation accuracy. Our numerical results showcase the superiority of semantic scheduling policies that adopt an integrated control and communication strategy. In essence, such policies can reduce the weighted sum of mean squared errors compared to traditional policies.

I. Introduction

Industrial internet of things (IIoT) devices are a staple of the fifth generation (5G) of wireless networks and beyond. The goal of IoT devices is to monitor, track, or control a system. Thereby, sensors record measurements from physical processes, and the measurements must be processed in real-time by the receiving devices. For instance, in control systems, actuators need to react immediately on variations within the measurement data. As a result, such actions must be performed in a time-critical manner while delivering accurate and error-free information [1]. Thereby, the dynamics of the different process systems can be different. Hence, not all data should be treated equally as the data transmitted by sensor can have a different semantics (meaning) than the ones sent by sensor . As a result, such semantics can determine the state of the overall system. As a result, it is necessary to consider the levels of significance [1], [2] and criticality requirements [3] while optimizing the overall control and communication system. This means that, latency and information freshness are not sufficient to satisfy the quality-of-service (QoS) of devices in such applications. For this reason, communication schemes should be designed to enhance information accuracy [4] by taking the dynamics of the processes into account [1], [5]. Nonetheless, the communication resources of the wireless medium are limited, and thus, various resource management and allocation schemes have been proposed to orchestrate and multiplex such resources in time, space and frequency. Here, one can adopt scheduling schemes, which assign different resource blocks to demanding IoT devices. In particular, coordinated scheduling schemes such as those in [6] and [7] employ a common coordination among different transmitters. Note that the implementation of a central coordinator may lead to complications in practice for IloT. Alternatively, un-coordinated or random access mechanism such as ALOHA (e.g. [8]–[11]) do not require a central coordination. In such schemes, the decision making mechanism for transmitters is performed locally and in a distributed manner. Notably, in ALOHA schemes, packet collisions due to simultaneous access are possible, which lead to additional decoding errors compared to coordinated scheduling schemes.