Joint Communication and Computation Optimization for Wireless Networked Control with URLLC

This paper studies the wireless control system at network edge, in which one base station (BS) coordinates the closed-loop wireless control of multiple subsystems each consisting of a plant, sensor, and actuator. In this system, the BS first collects the state information from the sensors of plants, then processes the information via edge computing, and finally sends the obtained command signals back to the actuators for controlling the plants. In particular, we consider the ultra-reliable low-latency communication (URLLC) for the state and command signal transmission, by using the rate formulas based on short-packet communication. Under this setup, we first present a time-division-multiple-access (TDMA) protocol for coordinating the sensing, communication, and computation among the multiple plants. Then, we jointly optimize the communication and computation resource allocations to minimize the closed-loop control latency while ensuring the stability of the controlled plants. Though the considered problem is difficult to solve, we transform it into a non-convex problem with semi-definite constraints, and then present an efficient solution via the techniques of alternating optimization and convex approximation. Numerical results show that the proposed solution efficiently reduces the closed-loop control latency as compared to other benchmark schemes with heuristic resource allocations.