Opportunistic Control Over Shared Wireless Channels

TLDR

The study examines wireless control architectures where multiple control loops share a common wireless medium. The authors aim to design channel‑aware scheduling and power allocation that minimize total power consumption while meeting control performance requirements for all systems. They develop an offline optimization and an online protocol that opportunistically schedule transmissions on non‑overlapping frequencies and adapt power to channel conditions, guaranteeing each system’s Lyapunov function decreases at a specified rate. Simulations demonstrate substantial power savings compared to non‑channel‑aware schemes.

Abstract

We consider a wireless control architecture with multiple control loops over a shared wireless medium. A scheduler observes the random channel conditions that each control system experiences over the shared medium and opportunistically selects systems to transmit at a set of non-overlapping frequencies. The transmit power of each system also adapts to channel conditions and determines the probability of successfully receiving and closing the loop. We formulate the optimal design of channel-aware scheduling and power allocation that minimize the total power consumption while meeting control performance requirements for all systems. In particular, it is required that for each control system a given Lyapunov function decreases at a specified rate in expectation over the random channel conditions. We develop an offline algorithm to find the optimal communication design, as well as an online protocol which selects scheduling and power variables based on a random observed channel sequence and converges almost surely to the optimal operating point. Simulations illustrate the power savings of our approach compared to other non-channel-aware schemes.