Impact of Time Synchronization on Time Aware Shaper Scheduling in Time Sensitive Networks

Industry 4.0 applications, such as smart factories and robotics, demand networks with guaranteed low latency and minimal jitter. Ethernet is a popular communications technology that is cost-effective and widely used. However, for Ethernet to meet these time-sensitive requirements, it must be enhanced. To address this, the IEEE Time-Sensitive Networking (TSN) Task Group has developed standards to extend Ethernet capabilities, including IEEE 802.1Qbv (Time-Aware Shaper, or TAS) for deterministic scheduling. Furthermore, for TAS to perform, all devices across the network require precise periodic time synchronization. Existing TAS scheduling solutions often assume perfect synchronization or use worst-case errors. As a result, these methods either produce idealized schedules that may fail in real networks or lead to inefficient bandwidth usage. This thesis shows that incorporating realistic time synchronization parameters into TAS scheduling significantly improves bandwidth efficiency. Compared to conventional worst-case approaches, using network-obtained synchronization parameters reduces unnecessary delays and achieves 26% to 34% lower end-to-end latency based on the studies conducted in this thesis. Additionally, this thesis shows that the deterministic latency and jitter bounds can be analytically derived using network-obtained synchronization and topology information, without the need for solving complex optimization and heuristics solutions. However, even with improvements to the conventional approaches, queuing delays, and jitters still persist. Therefore, to address this, another notable contribution in this thesis is the development of an alternative scheduling method that completely eliminates queuing delays, enabling time-sensitive streams to meet even the most stringent deadlines. Further refinements to the scheduling method using network-derived synchronization data improves bandwidth efficiency by 15% to 65% without compromising latency guarantees. Finally, this thesis highlights the interdependence between time synchronization and TAS scheduling. The network overheads are minimized by jointly optimizing synchronization periodicity while deriving TAS schedules. Overall, this thesis underscores that effective deployment of TAS requires tight integration with network time synchronization mechanisms.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Engineering, Electrical and Computer

Grantor dc:publisher

Carleton University

Year dc:date.issued

2025

Author dc:creator

• Ghosh, Aviroop

Statement dc:rights

• Copyright © 2025 the author(s). Theses may be used for non-commercial research, educational, or related academic purposes only. Such uses include personal study, distribution to students, research and scholarship. Theses may only be shared by linking to the Carleton University Institutional Repository and no part may be copied without proper attribution to the author; no part may be used for commercial purposes directly or indirectly via a for-profit platform; no adaptation or derivative works are permitted without consent from the copyright owner.

Language dc:language.iso

en

DOI

10.22215/etd/2025-16804

OAI identifier oai:identifier

oai:carleton.scholaris.ca:20.500.14718/44831