Why Is Network Reselection an Issue for Cross-Border Vehicular Applications?

Safety-critical advanced driver-assistance systems (ADAS) are expected to benefit from cellular vehicle-to-everything communication, providing both short-range and long-range wireless connectivity between vehicles and road/network infrastructure equipment. However, upon switching between adjacent coverage areas belonging to different network operators, the wireless connectivity may be discontinued. This issue prevents network service continuity and causes interruption of ADAS service availability. In this paper, we aim at assessing the average duration of service interruption due to such network reselection procedures. We provide performance evaluation results highlighting that there is a wide gap between the best case scenario and the worst case scenario. Moreover, we propose a simple heuristic to limit the downside of the lack of cooperation between network operators; our heuristic algorithm, which does not require a tight integration between the operators, performs much better than the worst case and it is fairly comparable with the best case scenario. Nevertheless the present work highlights the importance of a tighter integration between network operators to reduce the delay to the minimum.