Performance Analysis of High-Definition Map Distribution in VANET

High-definition (HD) map is a key enabler to achieving fully autonomous driving. Unlike traditional multimedia data, HD map consists of hybrid data types including 3D point clouds, images, GPS, etc. However, transporting HD map data to and from autonomous vehicles is challenging. IEEE 802.11p Vehicular ad-hoc networks (VANETs) are the de facto standard to establish short-range communications for vehicle-to-everything (V2X). One of the key limitations of 802.11p is ensuring quality of service for HD map traffic, since it might be categorised as best-effort (low priority) between all four access categories (AC) best-effort, background, voice, and video. We proposed a new AC for HD map traffic in this paper to address the aforementioned limitation. We also demonstrate the benefits of using the new AC, as well as the importance of selecting the appropriate channel control parameters within the AC, such as contention window (CW) and Arbitrary Inter-Frame Space (AIFS). Various values of CW and AIFS were examined under dynamic vehicular density and mobility to investigate end-to-end latency and throughput. Experimental results reveal that both, the average delay and throughput of HD map traffic improved by 80%, with the new AC. Furthermore, the delay manifested a steady behavior of 2.3 seconds for thirty, forty, and fifty vehicles. For the selection of AFS and CW parameters, a correlation is observed between vehicular mobility and density.