A Geographical Routing Protocol for Highly-Dynamic Aeronautical Networks Kevin Peters, Abdul Jabbar, Egemen K. C ¸etinkaya, James P. G. Sterbenz Information and Telecommunication Technology Center, The University of Kansas Lawrence, Kansas, USA {kevjay, jabbar, ekc, jpgs}@ittc.ku.edu Abstract—Emerging networked systems require domain- specific routing protocols to cope with the challenges faced by the aeronautical environment. We present a geographic routing protocol AeroRP for multihop routing in highly dynamic MANETs. The AeroRP algorithm uses velocity-based heuristics to deliver the packets to destinations in a multi-Mach speed environment. Furthermore, we present the decision metrics used to forward the packets by the various AeroRP operational modes. The analysis of the ns-3 simulations shows AeroRP has several advantages over other MANET routing protocols in terms of PDR, accuracy, delay, and overhead. Moreover, AeroRP offers performance tradeoffs in the form of different AeroRP modes. Index Terms—geographic routing, AeroRP, high-speed, aero- nautical networks, ns-3 simulation, accuracy metric, MANET, disruption-tolerant network (DTN) I. I NTRODUCTION Emerging airborne networked systems require multihop transmission of data in a highly dynamic environment. An example motivation is the iNET telemetry application [1]– [4]. However, the highly dynamic environment poses unique challenges such as short transmission times between nodes due to speed and limited connectivity due to mobility [5], [6]. Therefore, a domain specific geolocation-based routing proto- col, AeroRP, is proposed for multihop routing in networked systems [7]. The main focus of AeroRP is to efficiently route data packets, such as telemetry data, among airborne nodes (ANs) to a ground station (GS) as shown in Figure 1. The ANs must use themselves or relay nodes (RNs) as next hops in order for the packets to reach their destination as the AN may never be within transmission range of the GS within a reasonable amount of time. Mobile ad hoc networks (MANETs) are self-configuring wireless networks with no pre-established infrastructure. Rout- ing packets among a network in which a specific hop-by-hop path will most likely not persist must be a major consideration by the MANET routing protocol since ANs can have relative speeds up to Mach 7 [5], [8]. These fast moving nodes create a unique challenge for routing packets when connectivity among the nodes is very intermittent and episodic. Thus, traditional MANET routing protocols are not suitable for such environments. Previous geographic-based routing protocols generally do not consider high velocity of the nodes. In this paper, we first present an overview of the AeroRP protocol and algorithm to make decisions to forward the GS GS RN AN AN ANs Internet GW GW AN  airborne node RN  relay node GS  ground station GW  gateway Fig. 1. Aeronautical network architecture packets to the next best available hop. We also present per- formance results of the AeroRP routing protocol and compare its performance to traditional MANET protocols. We show that certain modes of AeroRP outperform the MANET routing protocols in terms of successful packet delivery, accuracy, overhead, and delay in this highly-dynamic environment. The rest of the paper is organized as follows: Section II discusses background information specific to geographic rout- ing protocols, some specific geographic routing protocol im- plementations, and routing data in high speed networks. The AeroRP routing protocol is detailed in Section III. Then, in Section IV, we present the simulation results comparing AeroRP to traditional MANET protocols in a highly dynamic network. Finally, conclusions are presented in Section V. II. BACKGROUND The various geographic routing survey papers [9]–[11] break down different geographic forwarding decisions into MFR (most forward with radius r), NFP (nearest with for- ward progress), and compass. MFR is the most intuitive and forwards the packet to the node that makes the most forward progress with respect to the source and destination. NFP IEEE WCNC 2011 - Network 978-1-61284-254-7/11/$26.00 ©2011 IEEE 492