Segment Routing IPv6 Based Low Latency Mobile Network for Vehicular Communications towards Automated Driving Era

Japan recently suffers from a serious social issue that is becoming difficult to maintain not only logistics services but also regional transportation services of route buses and district railways nationwide due to the progress of labor shortage and regional depopulation caused by declining birthrate and aging population. Automated driving technologies, including Connected and Automated Vehicles (CAVs), are indispensable to realizing sustainable logistics and regional transportation services, and require the reduction of further communication latency in mobile networks that support the technologies. Unfortunately, the current mobile networks, i.e., 4G and 5G specified by 3GPP, suffer from a problem where the communication latency increases with the distance between the serving base stations (BSs) and a mobile core network (CN) node over the transport network (TN). This problem becomes more severe, especially in areas far from the backbone network station accommodating the CN. This is because the User plane (U-plane) packets shall always be passed through the CN in the current mobile networks. In order to solve this problem in the current mobile networks, Segment Routing IPv6 for the Mobile User Plane (SRv6 MUP) that integrates 3GPP-based mobile network with Segment Routing over IPv6 (SRv6), has been proposed within IETF. SRv6 MUP is designed to allow the U-plane packets to bypass the CN and is equipped with the functionality to advertise the IP routing information to TN among BSs and CN in consideration of the user equipment (UE) mobility, including inter-cell handover (HO) between BSs. In the mobile network applied with SRv6 MUP, this design and functionality enable optimizing the U-plane packet route. This achieves not only low-latency edge computing but also low-latency Peer-to-Peer (P2P) communication among UEs since the U-plane packets bypass the CN. This paper first overviews SRv6 MUP technology as well as describes its distinctive mechanisms that support UE mobility, including HO between radio BSs, and that optimize the U-plane packet routes. Next, this paper proposes a novel concept of low-latency Vehicle-to-Network (V2N) and Vehicle-to-Network-to-Everything (V2N2X) utilizing the distinctive mechanisms of SRv6 MUP towards automated driving era. Then, it also presents field trial tests of low latency in-vehicle UE-to-UE communication applying SRv6 MUP under a live commercial 5G StandAlone (SA) network environment assuming application to low-latency Vehicle-to-Network-to-Vehicle (V2N2V), and the results demonstrate the effectiveness of SRv6 MUP in practical network environments.