# A Practical Approach to Deploying a Drone-Based Message Ferry in a Disaster Situation +
###### Abstract  
Unmanned aerial vehicles (UAVs) are commonly used in disaster recovery efforts to confirm the extent of the damage caused by a large-scale disaster and to ensure that adequate information about the affected area is gathered. UAV usage in a disaster situation is not limited to information gathering, but its functions further extend to network communication functions such as a communication relay, mobile base station, etc. Conversely, using UAVs as communication relays or base stations (e.g., as a temporary mobile base station) is subject to some limitations such as bad weather and limited energy, which affect the timely collection and delivery of information to and from a disaster area. Therefore, an approach to improve the information collection and delivery in a disaster area while ensuring urgent network restoration is necessary. In this paper, we introduce a practical approach to deploying a drone-based message ferry to improve the timely collection and delivery of information in a disaster situation. Specifically, a locally accessible cloud system (LACS), which we previously developed for urgent local network restoration in a disaster affected area, is attached to a drone to form a message ferry. In order to improve the information collection and delivery, the message ferry is deployed from the local headquarters (i.e., local government office or disaster response coordination center) to carry information to and from a standalone LACS installed at each disaster shelter. We measure the achievable data rate of inter-LACS data transfer (i.e., message ferry and a standalone LACS) through experiment. Thereafter, we estimate and confirm the effective transmission speed to transfer data from the local headquarters to the disaster shelters using average achievable data rate obtained from the experiment in order to extend the LACS services and functions. Our experimental results and analysis suggest that the proposed message ferry is more advantageous to transfer a large amount of data (e.g., 300 MB) at a high speed in the hundred meter to ten kilometer range. A practical Approach to Deploying a Drone-Based Message Ferry in a Disaster Situation +
Footnote †: This material was presented in part at the ICT-DM 2021 conference, Hangzhou, China, 3-5 December 2021. Footnote †: These authors contributed equally to this work. Footnote †: This material was presented in part at the ICT-DM 2021 conference, Hangzhou, China, 3-5 December 2021. Footnote †: These authors contributed equally to this work. Footnote †: This material was presented in part at the ICT-DM 2021 conference, Hangzhou, China, 3-5 December 2021. Footnote †: These authors contributed equally to this work. Footnote †: This material was presented in part at the ICT-DM 2021 conference, Hangzhou, China, 3-5 December 2021. Footnote †: These authors contributed equally to this work. Footnote †: This material was presented in part at the ICT-DM 2021 conference, Hangzhou, China, 3-5 December 2021. Footnote †: These authors contributed equally to this work. Footnote †: This material was presented in part at the ICT-DM 2021 conference, Hangzhou, China, 3-5 December 2021. Footnote †: These authors contributed equally to this work. wireless link that is essential for such a system needs a substantial amount of installation time and in some instances physical installation is not possible in the disaster area. Moreover, previous studies utilized a mobile ad-hoc network (MANET) [3], although users need to be in constant connection with one another in order to be able to share vital information. Furthermore, a delay tolerant network (DTN) [4] is used when a steady network connection is difficult to establish when there is a communication failure, which is often experienced in the aftermath of a large-scale disaster. In the DTN, messages are stored by users and when in close proximity with other users, the stored messages can be forwarded. This is commonly referred to as a store-and-carry forward method.