Boeing Research & Technology

P.O. Box 3707 Seattle WA 98124 USA fltemplin@acm.org

I-D Internet-Draft Urban Air Mobility concerns the introduction of manned and unmanned aircraft within urban environments, while Intelligent Transportation Systems have traditionally considered only terrestrial vehicles operating on city streets and highways. This document considers the implications for introduction of low-altitude aircraft within urban environments operating in harmony with ground transportation.

Urban Air Mobility (UAM) concerns the introduction of manned and unmanned aircraft within urban environments. Autonomy will play a pivotal role in the acceptance of low-altitude operations for aerial vehicles operating in harmony with traditional ground transportation and pedestrian traffic. The UAM vision therefore builds on evolving works on Unmanned Air Systems (UAS), including the NASA UAS Traffic Management (UTM) service model . Use cases for autonomous aircraft in the UAM vision are endless, and include personal air vehicles, flying taxis, parcel delivery, law enforcement and countless others. Major industry leaders such as Airbus and Boeing have accordingly begun to articulate their UAM strategies. Programs such as Uber Elevate anticipate deployment as early as within the next 2-5 years. With the advent of the UAM vision and its related initiatives, questions arise as to how the new model will be harmonized with the existing terrestrial mobility environment. Directions for modernizing terrestrial mobility are emerging in programs such as the US Department of Transportation's Intelligent Transportation Systems and anticipate an increasing role for Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communications. The IETF recognizes this need and has formed the IP Wireless Access in Vehicular Environments (IPWAVE) working group with charter to produce a document that will specify the mechanisms for transmission of IPv6 datagrams over dedicated short-range wireless communications media. This document anticipates a need to provide a unified V2V and V2I service for all urban mobility agents, including both terrestrial and airborne. Urban air vehicles will employ Vertical Takeoff And Landing (VTOL) and will operate at altitudes below 400 feet, such that communications range overlap with terrestrial vehicles will be inevitable and commonplace. This work therefore proposes that urban air vehicles also employ a short-range V2V / V2I communications capability using the same types of wireless networking gear used in the terrestrial domain (e.g., DSRC, C-V2X, etc.). The urban mobility landscape is evolving from a two dimensional to a three dimensional environment. Vehicles both on the ground and in the air will therefore need to coordinate with one another on a V2V and V2I basis even when supporting communications infrastructure such as cell towers are unavailable or otherwise too congested to support realtime exchanges. The ipwave working group is therefore advised to consider the rapidly emerging and inevitable Urban Air Mobility future.

Terms such as Intelligent Transportation Systems (ITS), Urban Air Mobility (UAM), Unmanned Air Systems (UAS), UAS Traffic Management (UTM) and many others apply to the emerging urban mobility landscape. IETF keywords per are not applicable within the scope of this document.

Urban Air Mobility and Intelligent Transportation System concepts apply within all major urban areas worldwide.

UAM end systems will often have multiple diverse wireless transmission media interfaces (including cellular, SATCOM, short-range omni-directional, etc.) offered by different data link service providers. In order to provide mobility, multihop and multilink services, UAM end systems can employ an Overlay Multilink Network (OMNI) interface as a Non-Broadcast Multiple Access (NBMA) virtual link connection for V2V/V2I communications over the underlying data links. The OMNI interface and link model provide a nexus for multilink, multihop, multicast and mobility coordination using standard IPv6 Neighbor Discovery (ND) messaging according to the NBMA principle. The OMNI model therefore supports efficient UAM internetworking services with no need for adjunct mobility messaging, nor modifications to the IPv6 ND messaging services or link model.

Early prototyping and testing are underway.

This document introduces no IANA considerations.

Communications networking security is necessary to preserve the confidentiality, integrity and availability necessary for V2V and V2I coordinations.

Discussions on the IETF ipwave list (its@ietf.org) helped motivate this document. This work is aligned with the NASA Safe Autonomous Systems Operation (SASO) program under NASA contract number NNA16BD84C. This work is aligned with the FAA as per the SE2025 contract number DTFAWA-15-D-00030. This work is aligned with the Boeing Commercial Airplanes (BCA) Internet of Things (IoT) and autonomy programs. This work is aligned with the Boeing Information Technology (BIT) MobileNet program.

<< RFC Editor - remove prior to publication >> Changes from -01 to -02: Included OMNI interface Version and reference update Changes from -00 to -01: Version and reference update