The use of flying platforms such as unmanned aerial vehicles (UAVs), popularly known as drones, is rapidly growing. In particular, with their inherent attributes such as mobility, flexibility, and adaptive altitude, UAVs admit several key potential applications in wireless systems. On the one hand, UAVs can be used as aerial base stations to enhance coverage, capacity, reliability, and energy efficiency of wireless networks. On the other hand, UAVs can operate as flying mobile terminals within a cellular network. Such cellular-connected UAVs can enable several applications ranging from real-time video streaming to item delivery. In this paper, a comprehensive tutorial on the potential benefits and applications of UAVs in wireless communications is presented. Moreover, the important challenges and the fundamental tradeoffs in UAV-enabled wireless networks are thoroughly investigated. In particular, the key UAV challenges such as 3D deployment, performance analysis, channel modeling, and energy efficiency are explored along with representative results. Then, open problems and potential research directions pertaining to UAV communications are introduced. Finally, various analytical frameworks and mathematical tools, such as optimization theory, machine learning, stochastic geometry, transport theory, and game theory are described. The use of such tools for addressing unique UAV problems is also presented. In a nutshell, this tutorial provides key guidelines on how to analyze, optimize, and design UAV-based wireless communication systems.

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A Tutorial on UAVs for Wireless Networks: Applications, Challenges, and Open Problems

One of the most important design problems for multi-UAV (Unmanned Air Vehicle) systems is the communication which is crucial for cooperation and collaboration between the UAVs. If all UAVs are directly connected to an infrastructure, such as a ground base or a satellite, the communication between UAVs can be realized through the in-frastructure. However, this infrastructure based communication architecture restricts the capabilities of the multi-UAV systems. Ad-hoc networking between UAVs can solve the problems arising from a fully infrastructure based UAV networks. In this paper, Flying Ad-Hoc Networks (FANETs) are surveyed which is an ad hoc network connecting the UAVs. The differences between FANETs, MANETs (Mobile Ad-hoc Networks) and VANETs (Vehicle Ad-Hoc Networks) are clarified first, and then the main FANET design challenges are introduced. Along with the existing FANET protocols, open research issues are also discussed.

Flying Ad-Hoc Networks (FANETs)

The use of flying platforms such as unmanned aerial vehicles (UAVs), popularly known as drones, is rapidly growing. In particular, with their inherent attributes such as mobility, flexibility, and adaptive altitude, UAVs admit several key potential applications in wireless systems. On the one hand, UAVs can be used as aerial base stations to enhance coverage, capacity, reliability, and energy efficiency of wireless networks. On the other hand, UAVs can operate as flying mobile terminals within a cellular network. Such cellular-connected UAVs can enable several applications ranging from real-time video streaming to item delivery. In this paper, a comprehensive tutorial on the potential benefits and applications of UAVs in wireless communications is presented. Moreover, the important challenges and the fundamental tradeoffs in UAV-enabled wireless networks are thoroughly investigated. In particular, the key UAV challenges such as three-dimensional deployment, performance analysis, channel modeling, and energy efficiency are explored along with representative results. Then, open problems and potential research directions pertaining to UAV communications are introduced. Finally, various analytical frameworks and mathematical tools such as optimization theory, machine learning, stochastic geometry, transport theory, and game theory are described. The use of such tools for addressing unique UAV problems is also presented. In a nutshell, this tutorial provides key guidelines on how to analyze, optimize, and design UAV-based wireless communication systems.

The days where swarms of unmanned aerial vehicles (UAVs) will occupy our skies are fast approaching due to the introduction of cost-efficient and reliable small aerial vehicles and the increasing demand for use of such vehicles in a plethora of civil applications. Governments and industry alike have been heavily investing in the development of UAVs. As such it is important to understand the characteristics of networks with UAVs to enable the incorporation of multiple, coordinated aerial vehicles into the air traffic in a reliable and safe manner. To this end, this survey reports the characteristics and requirements of UAV networks for envisioned civil applications over the period 2000–2015 from a communications and networking viewpoint. We survey and quantify quality-of-service requirements, network-relevant mission parameters, data requirements, and the minimum data to be transmitted over the network. Furthermore, we elaborate on general networking related requirements such as connectivity, adaptability, safety, privacy, security, and scalability. We also report experimental results from many projects and investigate the suitability of existing communication technologies for supporting reliable aerial networking.

Survey on Unmanned Aerial Vehicle Networks for Civil Applications: A Communications Viewpoint

In this letter, the efficient deployment of multiple unmanned aerial vehicles (UAVs) acting as wireless base stations that provide coverage for ground users is analyzed. First, the downlink coverage probability for UAVs as a function of the altitude and the antenna gain is derived. Next, using circle packing theory, the 3-D locations of the UAVs is determined in a way that the total coverage area is maximized while maximizing the coverage lifetime of the UAVs. Our results show that, in order to mitigate interference, the altitude of the UAVs must be properly adjusted based on the beamwidth of the directional antenna as well as coverage requirements. Furthermore, the minimum number of UAVs needed to guarantee a target coverage probability for a given geographical area is determined. Numerical results evaluate various tradeoffs.

Efficient Deployment of Multiple Unmanned Aerial Vehicles for Optimal Wireless Coverage

An important problem in Wireless Sensor Networks (WSN) is the occurrence of failures that lead to the disconnection of parts of the network, compromising the final results achieved by the WSN operation. A way to overcome such problem is to provide a reliable connection to support the connectivity via other types of nodes that communicate with the sensor nodes. This paper proposes the usage of a network composed by Unmanned Aerial Vehicles (UAVs) as a relay network to guarantee the delivery of data produced by WSN nodes on the ground to the users. Results from simulations of the proposed technique are provided and discussed.

UAV relay network to support WSN connectivity

For the evaluation of wireless network protocols, simulation has established itself as a good compromise between cost and complexity, on the one hand, and accuracy of results, on the other hand. Most established network simulators, however, were originally developed for wired networks and only later extended to the wireless domain. Some simulators like Opnet are not even restricted to communication networks at all, but can be used to simulate all kinds of networked systems. In this paper, we present ShoX, a network simulator explicitly designed for the simulation of wireless networks. Together with its strong GUI support, this allows a very efficient development and evaluation of network protocols without any considerable learning curve. All relevant concepts known from the domain of wireless networks like nodes, links, OSI layers, packets, mobility, signal propagation and traffic models are directly available. Defining new layers, packets or models is as easy as subclassing the existing abstract classes which ensures at compile time that all required methods are provided by the user. ShoX is completely based on Java and XML, thus superseding to learn unfamiliar languages like Tcl or NED. It features an integrated GUI for configuration, visualization and statistics.

ShoX: An Easy to Use Simulation Platform for Wireless Networks

A new challenge in the sensor network area is the coordination of heterogeneous sensors (with different sensing, mobility and computing capabilities) in an integrated network. This kind of sensor networks have clearly high relevance in surveillance systems, in which both low-end static ground sensor nodes and more sophisticated sensors carried by mobile platforms, such as Unmanned Aerial Vehicles (UAVs), cooperate. This paper provides an analysis of two different strategies to guide the collaboration among the sensor nodes mentioned above, applied to area surveillance systems. The first analyzed problem is related to the choice of the UAV instance that will respond to a given alarm issued by a ground sensor node. The second issue is the estimation of the response time until any UAV can be engaged in handling an alarm and effectively handles it. Two strategies are introduced and compared: one based on a pheromone inspired approach and another based on utility functions inspired on risk profiles that models decisions of investors in the stock market.

Evaluation of coordination strategies for heterogeneous sensor networks aiming at surveillance applications

Real-time applications usually are executed on top of a Real-time Operating System (RTOS). Specific scheduling algorithms can be designed. When possi- ble, static cyclic schedules are calculated off-line. If more flexibility is needed on-line techniques are applied. These algorithms are bound to priorities which can be assigned statically or dynamically. Designing a proper RTOS architec- ture needs some delicate decisions. The basic services like process manage- ment, inter-process communication, interrupt handling, or process synchroniza- tion have to be provided in an efficient manner making use of a very restricted resource budget. Various techniques like library-based approaches, monolithic kernels, microkernels, or virtual machines/exokernels are applied, based on spe- cific demands. Safety critical application can be supported by separation of ap- plications either in the time or the space domain. Multi-core architectures need special techniques for process management, memory management, and synchro- nization. The upcoming Wireless Sensor Networks (WSN) generate special de- mands for RTOS support leading to dedicated solutions. Another special area is given by multimedia applications. Very high data rates have to be supported un- der (soft) RT constraints. Based on the used encoding techniques (e.g. MPEG) dedicated solutions can be created.

https://www.springer.com/cda/content/document/cda_downloaddocument/9781402094354-c2.pdf?SGWID=0-0-45-699603-p173865105

Basic Concepts of Real Time Operating Systems

This paper presents a bio-inspired networking strategy to support the cooperation between static sensors on the ground and mobile sensors in the air to perform surveillance missions in large areas. The goal of the proposal is to provide low overhead in the communication among sensor nodes, while allocating the mobile sensors to perform sensing activities requested by the static ones. Simulations have shown that the strategy is efficient in maintaining low overhead and achieving the desired coordination.

/pdf/cooperation-among-wirelessly-connected-static-and-mobile-1p46wkcnbs.pdf

Tales Heimfarth

Papers

UAV relay network to support WSN connectivity

ShoX: An Easy to Use Simulation Platform for Wireless Networks

Evaluation of coordination strategies for heterogeneous sensor networks aiming at surveillance applications

Basic Concepts of Real Time Operating Systems

Cooperation among Wirelessly Connected Static and Mobile Sensor Nodes for Surveillance Applications