A protocol for loosely time-triggered architectures

Abstract

A distributed real-time control system has a time-triggered nature, just because the physical system for control is bound to physics. Loosely Time-Triggered Architectures (LTTA) are a weaker form of the strictly synchronous Time-Triggered Architecture proposed by Kopetz, in which the different periodic clocks are not synchronized, and thus may suffer from relative offset or jitter. We propose a protocol that ensures a coherent system of logical clocks on the top of LTTA, and we provide several proofs for it, both manual and automatic, based on synchronous languages and associated model checkers. We briefly discuss how this can be used for correct deployment of synchronous designs on an LTTA.