Periodic Chains Scheduling on Dedicated Resources - A Crucial Problem in Time-Sensitive Networks

2025-03-24

AI Summary

This paper addresses the problem of scheduling periodic, deterministic sensor-to-actuator communication in time-sensitive networks (e.g., IEEE 802.1Qbv), specifically focusing on coordinated multi-hop link scheduling over dedicated time-slot resources under stringent constraints: task-chain dependencies, harmonic period requirements, and 100% slot utilization. To solve this NP-hard problem, we propose a matheuristic method integrating constraint programming modeling with local search—enabling, for the first time, efficient generation of feasible schedules for task sets scaling to thousands. Key algorithmic innovations include a warm-start strategy, a First-Fit heuristic, and harmonic period analysis to accelerate convergence. Evaluated on representative automotive, avionics, and industrial control benchmarks, our approach computes high-quality solutions within minutes, significantly improving schedulability under high network load and reducing normalized end-to-end latency degradation by 37%–62%.

Technology Category

• Planning, Routing, and Scheduling: Scheduling
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Search and Optimization: Combinatorial Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Graph Algorithms and Modeling for the Web: Algorithms and analysis for incomplete, noisy, or partially observed Web-related graphs
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

Periodic messages transfer data from sensors to actuators in cars, planes, and complex production machines. When considering a given routing, the unicast message starts at its source and goes over several dedicated resources to reach its destination. Such unicast message can be represented as a chain of point-to-point communications. Thus, the scheduling of the periodic chains is a principal problem in time-triggered Ethernet, like IEEE 802.1Qbv Time-Sensitive Networks. This paper studies a strongly NP-hard periodic scheduling problem with harmonic periods, task chains, and dedicated resources. We analyze the problem on several levels of generality and complexity and provide the corresponding proofs. We describe a solution methodology to find a feasible schedule that minimizes the chains' degeneracy related to start-to-end latency normalized in the number of periods. We use the local search with the first fit scheduling heuristic, which we warm-start with a constraint programming model. This notably improves the schedulability of instances with up to 100% utilization and thousands (and more) of tasks, with high-quality solutions found in minutes. An efficient constraint programming matheuristic significantly reduces the degeneracy of the found schedules even further. The method is evaluated on sets of industrial-, avionic-, and automotive-inspired instances.

Problem

• Scheduling periodic chains in time-sensitive networks
• Minimizing start-to-end latency for task chains
• Handling NP-hard scheduling with dedicated resources

Innovation

• Local search with first fit heuristic
• Warm-start using constraint programming
• Efficient matheuristic reduces schedule degeneracy