The Smart Highway to Babel: the coexistence of different generations of Intelligent Transport Systems
Oscar Amador, Ignacio Soto, Maria Calderon, Manuel Urueña
TL;DR
Problem: Coexistence of different generations of C-ITS protocols due to uneven technology readiness. Approach: evaluate two ETSI GeoNetworking releases (Release 1 and Release 2) in a highway scenario using a mixed-fleet simulation and measure throughput-related efficiency and safety metrics. Findings: when Release 1 and Release 2 are mutually intelligible, safety remains high, but resource efficiency degrades as the proportion of Release 2 nodes increases, with the total transmissions $N_{tx}$ rising and the Packet Delivery Ratio $PDR$ largely preserved for single-source scenarios. Significance: the results highlight the feasibility limits of mixed fleets and motivate interoperability strategies, such as upgrading legacy nodes to Release 2 or encapsulating newer messages to preserve safety while managing spectrum and contention; future work includes extending analyses to multi-source, multi-modal traffic and deeper compatibility mechanisms.
Abstract
The gap between technology readiness level in Cooperative Intelligent Transport Systems (C-ITS) and its adoption and deployment has caused a phenomenon where at least two types of network access technologies have to coexist. Furthermore, for the case of ETSI Intelligent Transport Systems protocols, work is being completed in Release 2 of the specification while Release 1 deployments are still underway. This, coupled with industry and consumer trends in the vehicle industry, is bound to cause a scenario where fully C-ITS-enabled vehicles have to coexist with non-C-ITS road users and, at the very least, with different versions of C-ITS. In this paper, we analyze the performance in terms of efficiency and safety of two releases of the ETSI GeoNetworking protocol, as well as a discussion on possible paths to tackle the upcoming compatibility and coexistence problems.