Performance and Service Continuity of HD Map Downloads in MEC-Enabled Cross-Border Mobile Radio Networks

Cooperative, Connected and Automated Mobility (CCAM) will enrich assisted and automated driving by exchange of information among vehicles (V2V), as well as between vehicles and the network, commonly also called ”cloud” or ”backend”, (V2N). HD Mapping is such a V2N use case where vehicles obtain up-to-date information about the roads they drive on. This includes lane markings and dedication of lanes, to e.g. better distinguish between parking vehicles and vehicles waiting at a traffic light, and road signs like speed limits. Such information can become outdated, e.g. due to road constructions, and vehicles therefore download it on-the-fly before entering corresponding areas. Such HD map tile downloads must be seamlessly enabled and especially should not be interrupted when crossing a country border and with that also switching between different Mobile Network Operators (MNOs). It is furthermore a candidate service for Mobile Edge Cloud (MEC) deployment, as it might benefit from faster HD map tile transmissions from reduced round trip times (RTTs) enabled by MEC-hosting. This paper evaluates the performance gain MEC-hosting has over hosting on the public Internet and shows how seamless cross-MNO service continuity is achieved by enabling handover across different MNOs. Results from corresponding trials at the AstaZero automotive test ground are presented showing no noticeable effect on use case performance when handing over between the two mobile networks. Furthermore, it is shown that bulk-data transmission use cases like HD Mapping, using webserver download with TCP, benefit from reduced RTT from MEC-hosting through shorter HD map tile download times. In our setup 15 ms reduced RTT resulted in 15% shorter download
times.