Emerging Remote Piloting (RP) operations of electrified Unmanned Aerial Vehicles (UAVs) demand low-latency and high-quality video delivery to conduct safe operations in the low-altitude airspace. Although cellular networks are one of the prominent candidates to provide connectivity for such operations, their ground-centric nature limits their capabilities in achieving seamless and reliable aerial connectivity. In this paper, we study the feasibility of supporting RP operations with low latency and high-quality video delivery over commercial cellular networks. By setting up an adaptive bitrate video transmission pipeline with the Google Congestion Control (GCC) and Self-Clocked Rate Adaptation for Multimedia (SCReAM) Congestion Control (CC) algorithms, we analyze the video delivery performance for the RP application requirements and compare the performance of GCC and SCReAM against constant bitrate video delivery. Our results show that low-latency video delivery with < 300 ms playback latency between full-HD and 4K resolution can be maintained up to about 95% of the time in the air. While static bitrate video delivery outperforms adaptive streaming in urban location with abundant link capacity, the latter becomes advantageous in rural locations, where the link capacity is affected by fluctuations. Although the study's findings highlight the capabilities of cellular networks in delivering low-latency video for a safety-critical aerial service, we also discuss the potential improvements and future research challenges for enabling safe operations and meeting the service requirements using cellular networks. We release our collected traces and the video transmission pipeline as open-source to facilitate research in this field.

Network support for Unmanned Aerial Vehicles (UAVs) is raising an interest among researchers due to the strong potential applications. However, current knowledge on UAV data traffic is mainly based on conceptual studies and does not provide an in-depth insight on the data traffic properties. To close this gap, we present a measurement-based study analyzing in detail the Control and Non-payload Communication (CNPC) traffic produced by three different UAVs when communicating with their remote controller over 802.11 protocol. We analyze the traffic in terms of data rate, inter-packet interval and packet length distributions, and identify their main influencing factors. The data traffic appears neither deterministic nor periodic but bursty, with a tendency towards Poisson traffic. We further create an understanding on how the traffic of the investigated UAVs are internally generated and propose a model to analytically capture their traffic processes, which provides an explanation for the observed behavior. We implemented a publicly available UAV traffic generator "AVIATOR" based on the proposed traffic model and verified the model by comparing the simulated traces with the experimental results.

Sensors currently deployed on board have wired connectivity, which increases weight and maintenance costs for aircraft. Removing cables for wireless communications of sensors on board alleviates the cost, however, the powering of sensors becomes a challenge inside aircraft. Wireless power transfer (WPT) via radio-frequency (RF) signals is an emerging solution to remotely power sensors for battery-less operation with long-lived capacitors. In this article, we design a WPT system for aircraft IoT-type applications, including low data rate inside (LI) sensors by determining the number, location, and tilt angles of WPT transmitters given constraints based on the cabin geometry and duty cycle of the sensors. We formulate a robust optimization problem to address the WPT system design under channel uncertainties. We also derive an equivalent integer linear programming and solve that for an optimal deployment to satisfy the duty cycle requirements of LI sensors. We perform experiments inside the cabin to validate the wireless avionics intracommunications channel model. Our simulations demonstrate the feasibility of 90% robust design with 14 WPT transmitters for duty cycles less than 0.1% while keeping the human radiation exposure below the recommended reference value of 4.57 W/m2.

Wireless Avionics Intra-Communications (WAIC) is an emerging standard to migrate regulatory and safety-related applications from wired networks to wireless means in next generation aircraft. Removing most of the cables from the fuselage will benefit to the overall efficiency of aircraft. On the other hand, it is a difficult task to achieve the Quality of Service (QoS) performance of wired networks by wireless technologies. Also, the Radio Altimeter (RA) interference in the same spectrum is another obstacle to overcome. Current Long Term Evolution (LTE) and emerging Fifth Generation (5G) technologies advertise promising specifications that can meet the requirements of WAIC networks. Therefore, the goal of this study is to evaluate the feasibility of supporting high data rate WAIC applications with LTE/5G by means of analytical and experimental studies. Measurements conducted in unoccupied mockup cabin and outside environment show that at least one cellular technology can meet the requirements of high data rate WAIC classes in the absence of RA interference. In coupling scenarios, robustness strategies should be considered to improve the network resilience. Finally, a network architecture based on the experimental results is presented to show an example usage scenario of a high data rate WAIC network.