An adaptive real-time intravehicle network protocol for intelligent vehicle systems

Intelligent vehicle systems are inherently real-time systems that must perform continuous operations, often in harsh and unpredictable environments. The real-time network infrastructure is a key technology enabler for these systems. This effort presents an adaptive real-time network protocol (ARTNP) that provides multidimensional quality-of-service support for time-sensitive data under nominal conditions and during transient surges. Transient surges (e.g., the retransmission of corrupt or lost data and the unspecified arrival of sporadic messages) are problematic in that they can temporarily overload the network, causing message transmissions to be late. ARTNP is a fully distributed protocol that specifically addresses the issue of transient surges in network loading. Under nominal conditions, ARTNP can guarantee the time constraints of any messages at optimally high levels of network utilization. During a transient surge, ARTNP will detect the surge and alter the ordering of message transmissions to sustain the timely transmission of critical messages. The CAN protocol is selected as the underlying network, because of its wide spread use in vehicular systems. Simulations compare the performance of ARTNP against an optimal nonadaptive approach.