Heterogeneous Multilink Aggregation for Reliable UAV Communication in Maritime Search and Rescue Missions

Abstract

Recent technological advances are leading to increasing adoption of Unmanned Aerial Vehicles (UAV) in more and more application areas. The use of UAVs promises great potentials in finding missing persons during maritime search and rescue (SAR) missions. Hereby, communication between ground station and vehicle is essential in order to exchange data. Mandatory requirements are high reliability - especially for telemetry and control data - as well as high data rates as an enabler for high resolution thermal imaging and real-time video payloads. The underlying paper investigates the applicability of Long Term Evolution (LTE) for maritime SAR missions. Therefore, in a first step, a detailed maritime channel model is developed and implemented. The analytic evaluations show significant decreases in communication range in dependency of UAV flight and base station height and in dependency of the current wind speed. To compensate interferences and frequency-dependent propagation effects the authors propose the aggregation of multiple LTE links using the Multipath TCP (MPTCP) protocol. The proposed multi-link concept is evaluated and assessed in a close-to-reality evaluation. Hereby, a hardware-in-the-loop (HIL) experiment is conducted emulating a public mobile network operator in combination with a dedicated SAR-mission-only LTE link. The experiments highlight the applicability of LTE and MPTCP for maritime SAR missions. The heterogeneous multilink concept increases UAV communication range and achieves high reliability and data rates in the whole search area.