Ultra Reliable Hard Real-Time V2X Streaming with Shared Slack Budgeting

While autonomous driving roadmaps envision large data to be exchanged in V2X scenarios, current V2X communication standards only focus on reliable exchange of small objects. The Wireless Reliable Real-Time Protocol (W2RP) addresses this challenge, however, cannot properly handle scenarios where multiple applications share the channel especially as there are predetermined periodic and dynamic retransmissions phases for each data object. If transient error spikes occur, applications will compete for dynamic channel resources, potentially creating critical overload situations that can lead to safety violations. Furthermore, the channel is shared by multiple applications with different criticality, properties and constraints. We propose a two-level hierarchical approach that assigns a fixed budget to each node, with periodic and dynamic transmission parts of a node’s applications being scheduled by the node itself. Prioritization is used to differentiate applications based on their criticality, thereby enabling reliable data exchange for safety-critical applications. The concept was evaluated using an OMNeT++-based simulation of an Automated Valet Parking use case and proved highly effective in enabling safe sample exchange even under varying channel conditions, while offering significantly more efficient resource reservation compared to a static configuration.