Generalized Asynchronous Time-Triggered Scheduling for FlexRay

Florian Sagstetter, Martin Lukasiewycz, Samarjit Chakraborty

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


FlexRay is a hybrid communication protocol tailored to the requirements in the automotive domain, supporting both time-triggered and event-triggered communication with high data-rates. The time-triggered static segment is commonly used for in-vehicle communication while the event-triggered dynamic segment is used for diagnostics and configuration. This paper addresses the problem of synthesizing schedules for the static FlexRay segment for asynchronous scheduling, following the design approach of current automotive architectures. Previous approaches largely focused on FlexRay 2.1 while the few existing approaches for FlexRay 3.0 are nonoptimal in several aspects. As a remedy, our framework makes use of all new features of version 3.0 while supporting the still predominantly used FlexRay 2.1, making it backward compatible. The following approaches are proposed: 1) a single-stage integer linear programming (ILP) approach that determines an optimal solution but does not scale; 2) a multistage ILP for combining previously generated subsystem schedules to a global schedule. It clearly improves the scalability but is not optimal. The multistage approach allows to integrate and convert existing FlexRay 2.1 schedules into a FlexRay 3.0 schedule which is important for legacy reasons, i.e., to reduce testing and certification efforts; 3) a greedy heuristic which scales well and obtains high quality solutions in comparison with the optimal solution, but is unsuitable to integrate existing schedules; and 4) metaheuristic approaches based on genetic algorithms or simulated annealing to evaluate the benefits of the proposed approaches.

Original languageEnglish
Article number7471402
Pages (from-to)214-226
Number of pages13
JournalIEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Issue number2
StatePublished - Feb 2017


  • Automotive
  • FlexRay
  • schedule synthesis
  • time-triggered


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