A Deadline-Aware Scheduler for Smart Factory using WiFi 6

TL;DR

This paper introduces a deadline-aware scheduling algorithm for WiFi 6 in smart factories, optimizing packet delivery with varying deadlines to improve manufacturing data communication efficiency.

Contribution

It models the scheduling problem as a profit maximization, proves its NP-hardness, and proposes a 12-approximate local search algorithm tailored for WiFi 6's unique features.

Findings

The proposed algorithm outperforms existing benchmarks in simulations.

The scheduling problem is strongly NP-hard, justifying approximation approaches.

WiFi 6's resource units can be effectively utilized for deadline-sensitive data transmission.

Abstract

A key strategy for making production in factories more efficient is to collect data about the functioning of machines, and dynamically adapt their working. Such smart factories have data packets with a mix of stringent and non-stringent deadlines with varying levels of importance that need to be delivered via a wireless network. However, the scheduling of packets in the wireless network is crucial to satisfy the deadlines. In this work, we propose a technique of utilizing IEEE 802.11ax, popularly known as WiFi 6, for such applications. IEEE 802.11ax has a few unique characteristics, such as specific configurations of dividing the channels into resource units (RU) for packet transmission and synchronized parallel transmissions. We model the problem of scheduling packets by assigning profit to each packet and then maximizing the sum of profits. We first show that this problem is strongly NP-Hard, and then propose an approximation algorithm with a 12-approximate algorithm. Our approximation algorithm uses a variant of local search to associate the right RU configuration to each packet and identify the duration of each parallel transmission. Finally, we extensively simulate different scenarios to show that our algorithm works better than other benchmarks.