Delay Tolerant Packet Forwarding Algorithm Based on Location Estimation for Micro Aerial Vehicle Networks

Abstract

In search and rescue mission, micro aerial vehicles (MAVs) are typically used to capture image and video from an aerial perspective and transfer the data to the ground station. Because of the power limitation, a cluster of MAVs are required for a large search area, hence an ad-hoc wireless network must be maintained to transfer data more conveniently and fast. However, the unstable link and the intermittent connectivity between the MAVs caused by MAVs' movement may challenge the packet forwarding. This paper proposes a delay tolerant packet forwarding algorithm based on location estimation for MAV networks, called DTN est algorithm. In the algorithm, ferrying MAVs are used to transmit data between MAVs and the ground station, and the locations of both searching MAVs and ferrying MAVs are estimated to compute the distances between the MAVs and destination. The MAV that is closest to the destination is selected greedy to forward packet. If a MAV cannot find the next hop MAV using the greedy strategy, the packets will be stored and re-forwarded once again in the next time slot. The experiment results show that the proposed DTN est algorithm outperforms the typical DTN geo algorithm in terms of packet delivery ratio and average routing hops.Micro aerial vehicles (MAVs) which weigh only a few kilograms, have been widely used in many applications, such as aerial photography, agricultural monitoring, disaster relief, military and so on. MAVs are usually equipped with computing and wireless communication devices, sensors and cameras to collect image and video and transmit them to the ground station [1] [2]. With the characteristics of low cost, portability, and no casualty risk, MAVs have become a hotspot in both academic and industrial fields.A cluster of MAVs is usually required to complete large and complex tasks coordinately, since the energy, flight distance and communication range of each MAV are limited. The cluster of MAVs is typically organized as an ad-hoc multi-hop network to transmit data from MAVs to the ground station [3]. However, packet forwarding is a challenge in practical MAV networks because of unstable links and intermittent connectivity of the network caused by rapid movements of MAVs [4].Since global positioning system (GPS) and inertial measurement unit provide the location information of MAVs [5][6], Mozaffari et al. proposed a geographic routing based method to forward packets to the nodes that are spatially closer to the destination [7]. In practical applications, the motion and the unstable link of MAVs may change the topology of the network frequently, but these geographic routing methods are not adequate for MAV networks that face intermittent connectivity [8].To cope with intermittent connectivity, delay tolerant networking (DTN) is a feasible approach. Using the communication opportunity formed by nodes flying into each other's transmission range to transmit messages hop by hop, Raffelsberger et al. integrated the "store-carry-forward" with the adaptive routing method [9]. However, traditi...