Priority-Based V2X Message Scheduling and Performance Evaluation in a Congested Urban Intersection Using Veins.

Efficient message dissemination in congested urban environments is critical for reliable Vehi-cle-to-Everything (V2X) communications, especially for safety-critical applications like collision avoidance and emergency vehicle warnings. This study evaluates V2X performance under heavy load using the VEINS simulation framework, incorporating both queue-level behavior and pri-ority-based message scheduling. Results are reported as per-node averages across 104 vehicles. Each node generated an average of 30.29 WSMs but received only 4.22 messages, highlighting a significant bottleneck in network reachability. Queue saturation was widespread, with all nodes reaching maximum buffer depth, a mean queue length of 9.81 messages, and peaks of 18. High congestion also caused extensive packet loss, averaging 107.09 dropped messages per node, with a mean drop ratio of 79.3%, reaching up to 90.1%. Three scheduling strategies—FIFO, Strict Priority, and Hybrid—were evaluated. High-priority messages, such as emergency warnings, consistently achieved the lowest latency and highest packet delivery ratio. While Strict Priority improves critical traffic, it severely degrades lower-priority message delivery. The Hybrid scheduler provides the most balanced solution, reducing packet drops, stabilizing channel utili-zation, and maintaining acceptable latency across all message types, demonstrating the effec-tiveness of adaptive scheduling for robust V2X communication in dense urban scenarios.