INCUS: A communication protocol for safety critical distributed real time systems

Safety-critical, distributed real-time systems, such as avionics, automotive or factory automation and control systems, and the like, require efficient communication mechanism between their nodes in order to deliver information within defined time frames. Protocols that follow the time-triggered architecture paradigm guarantee timeliness under a given fault and load hypothesis through the use of a stringent, equivalently-spaced time division multiple access (TDMA) scheme. This, however, comes at the cost of poor channel and bandwidth utilisation in real-world scenarios where functionality and transmission requirements often differ considerably between nodes. Here, we propose a new approach and protocol, INCUS, that allows the slot length of nodes to be configured in accordance with their payload requirements. We show the feasibility of our approach while retaining the level of reliability required for safety-critical realtime systems. Our analysis shows an almost twofold improvement in efficiency in a typical automotive, brake by wire scenario.