Distributed Channel Access for Control Over Unknown Memoryless Communication Channels

TL;DR

This paper introduces a distributed, timer-based channel access method for control systems over shared wireless networks, capable of adapting to unknown channel conditions through learning algorithms, ensuring stability and collision-free operation.

Contribution

It presents a novel distributed deterministic channel access scheme that does not require explicit communication, and incorporates learning algorithms for unknown channel statistics.

Findings

Ensures collision-free channel access with learning algorithms.

Provides stability verification framework for the control system.

Demonstrates effectiveness through simulations and an illustrative example.

Abstract

We consider the distributed channel access problem for a system consisting of multiple control subsystems that close their loop over a shared wireless network. We propose a distributed method for providing deterministic channel access without requiring explicit information exchange between the subsystems. This is achieved by utilizing timers for prioritizing channel access with respect to a local cost which we derive by transforming the control objective cost to a form that allows its local computation. This property is then exploited for developing our distributed deterministic channel access scheme. A framework to verify the stability of the system under the resulting scheme is then proposed. Next, we consider a practical scenario in which the channel statistics are unknown. We propose learning algorithms for learning the parameters of imperfect communication links for estimating the channel quality and, hence, define the local cost as a function of this estimation and control performance. We establish that our learning approach results in collision-free channel access. The behavior of the overall system is exemplified via a proof-of-concept illustrative example, and the efficacy of this mechanism is evaluated for large-scale networks via simulations.