1 Unmanned Aerial Vehicles: A Survey on Civil Applications and Key Research Challenges Hazim Shakhatreh, Ahmad Sawalmeh, Ala Al-Fuqaha, Zuochao Dou, Eyad Almaita, Issa Khalil, Noor Shamsiah Othman, Abdallah Khreishah, Mohsen Guizani ABSTRACT the challenges facing UAVs within specific vertical domains The use of unmanned aerial vehicles (UAVs) is growing and across application domains. Also, these studies do not rapidly across many civil application domains including real- discuss practical ways to overcome challenges that have the time monitoring, providing wireless coverage, remote sensing, potential to contribute to multiple application domains. search and rescue, delivery of goods, security and surveillance, The authors in [1] present the characteristics and require- precision agriculture, and civil infrastructure inspection. Smart ments of UAV networks for envisioned civil applications over UAVs are the next big revolution in UAV technology promis- the period 2000–2015 from a communications and networking ing to provide new opportunities in different applications, viewpoint. They survey the quality of service requirements, especially in civil infrastructure in terms of reduced risks and network-relevant mission parameters, data requirements, and lower cost. Civil infrastructure is expected to dominate the the minimum data to be transmitted over the network for civil more that $45 Billion market value of UAV usage. In this applications. They also discuss general networking related re- survey, we present UAV civil applications and their challenges. quirements, such as connectivity, adaptability, safety, privacy, We also discuss current research trends and provide future security, and scalability. Finally, they present experimental insights for potential UAV uses. Furthermore, we present the results from many projects and investigate the suitability of key challenges for UAV civil applications, including: charging existing communications technologies to support reliable aerial challenges, collision avoidance and swarming challenges, and networks. networking and security related challenges. Based on our In [2], the authors attempt to focus on research in the areas review of the recent literature, we discuss open research chal- of routing, seamless handover and energy efficiency. First, they lenges and draw high-level insights on how these challenges distinguish between infrastructure and ad-hoc UAV networks, might be approached. application areas in which UAVs act as servers or as clients, Index Terms—UAVs, Wireless Coverage, Real-Time Monitor- star or mesh UAV networks and whether the deployment is ing, Remote Sensing, Search and Rescue, Delivery of goods, Secu- hardened against delays and disruptions. Then, they focus on rity and Surveillance, Precision Agriculture, Civil Infrastructure the main issues of routing, seamless handover and energy Inspection. efficiency in UAV networks. The authors in [7] survey Flying Ad-Hoc Networks (FANETs) which are ad-hoc networks con- I. INTRODUCTION necting the UAVs. They first clarify the differences between FANETs, Mobile Ad-hoc Networks (MANETs) and Vehicle UAVs can be used in many civil applications due to their Ad-Hoc Networks (VANETs). Then, they introduce the main ease of deployment, low maintenance cost, high-mobility and FANET design challenges and discuss open research issues. ability to hover [1]. Such vehicles are being utilized for real- In [8], the authors provide an overview of UAV-aided wireless time monitoring of road traffic, providing wireless coverage, communications by introducing the basic networking architec- arXiv:1805.00881v1 [cs.RO] 19 Apr 2018 remote sensing, search and rescue operations, delivery of ture and main channel characteristics. They also highlight the goods, security and surveillance, precision agriculture, and key design considerations as well as the new opportunities to civil infrastructure inspection. The recent research literature be explored. on UAVs focuses on vertical applications without considering The authors of [9] present an overview of legacy and emerg- ing public safety communications technologies along with the Hazim Shakhatreh, Zuochao Dou, and Abdallah Khreishah are with the Department of Electrical and Computer Engineering, New Jersey Institute of spectrum allocation for public safety usage across all the fre- Technology. (e-mail: fhms35,zd36,[email protected]) quency bands in the United States. They conclude that the ap- Ahmad Sawalmeh and Noor Shamsiah Othman are with the Department plication of UAVs in support of public safety communications of Electronics and Communication Engineering, Universiti Tenaga Nasional. (e-mail: [email protected],[email protected]) is shrouded by privacy concerns and lack of comprehensive Ala Al-Fuqaha is with the Department of Computer Science, West- policies, regulations, and governance for UAVs. In [10], the ern Michigan University, Kalamazoo, MI, 49008, USA. (e-mail: (ala.al- authors survey the applications implemented using cooperative [email protected]) Eyad Almaita is with the Department of Power and Mechatronics Engi- swarms of UAVs that operate as distributed processing system. neering, Tafila Technical University. (e-mail: ([email protected]) They classify the distributed processing applications into the Issa Khalil is with Qatar Computing Research Institute (QCRI), HBKU, following categories: 1) general purpose distributed processing Doha, Qatar. (e-mail: [email protected]) Mohsen Guizani is with the University of Idaho, Moscow, ID, 83844, USA. applications, 2) object detection, 3) tracking, 4) surveillance, (e-mail: [email protected]) 5) data collection, 6) path planning, 7) navigation, 8) collision 2 Fig. 1: Overall Structure of the Survey. TABLE I: COMPARISON OF RELATED WORK ON UAV SURVEYS IN TERMS OF APPLICATIONS Reference Providing wireless Remote sensing Real-Time Search and Delivery of Surveillance Precision Infrastructure coverage monitoring Rescue goods agriculture inspection [1] X X X X [2] X X [3] X X X X X [4] X [5] X [6] X This work X X X X X X X X TABLE II: COMPARISON OF RELATED WORK ON UAV SURVEYS IN TERMS OF NEW TECHNOLOGY TRENDS Reference Collision mmWave Free space Cloud Machine NFV SDN Image avoidance optical computing learning processing [1] X X [2] X X [3] X X [4] X X X [5] X [6] This work X X X X X X X X avoidance, 9) coordination, 10) environmental monitoring. various channel characterization efforts. They also review However, this survey does not consider the challenges facing the contemporary perspective of UAV channel modeling ap- UAVs in these applications and the potential role of new proaches and outline some future research challenges in this technologies in UAV uses. The authors of [3] provide a domain. comprehensive survey on UAVs, highlighting their potential UAVs are projected to be a prominent deliverer of civil ser- use in the delivery of Internet of Things (IoT) services from vices in many areas including farming, transportation, surveil- the sky. They describe their envisioned UAV-based architecture lance, and disaster management. In this paper, we review and present the relevant key challenges and requirements. several UAV civil applications and identify their challenges. We also discuss the research trends for UAV uses and future In [4], the authors provide a comprehensive study on the insights. The reason to undertake this survey is the lack of use of UAVs in wireless networks. They investigate two main a survey focusing on these issues. Tables I and II delineate use cases of UAVs; namely, aerial base stations and cellular- the closely related surveys on UAV civil applications and connected users. For each use case of UAVs, they present demonstrate the novelty of our survey relative to existing key challenges, applications, and fundamental open problems. surveys. Specifically, the contributions of this survey can be Moreover, they describe mathematical tools and techniques delineated as: needed for meeting UAV challenges as well as analyzing UAV-enabled wireless networks. The authors of [5] provide • Present the global UAV payload market value. The pay- a comprehensive survey on available Air-to-Ground channel load covers all equipment which are carried by UAVs measurement campaigns, large and small scale fading channel such as cameras, sensors, radars, LIDARs, communica- models, their limitations, and future research directions for tions equipment, weaponry, and others. We also present UAV communications scenarios. In [6], the authors provide the market value of UAV uses. a survey on the measurement campaigns launched for UAV • Provide a classification of UAVs based on UAV en- channel modeling using low altitude platforms and discuss durance, maximum altitude, weight, payload, range, fuel 3 type, operational complexity, coverage range and appli- Europe [16]. The payload covers all equipment which are cations. carried by UAVs such as cameras, sensors, radars, LIDARs, • Present UAV civil applications and challenges facing communications equipment, weaponry, and others [17]. Radars UAVs in each application domain. We also discuss the and communications equipment segment is expected to dom- research trends for UAV uses and future insights. The inate the global UAV payload market with a market share of UAV civil applications covered in this survey include: close to 80%, followed by cameras and sensors segment with real-time monitoring of road traffic, providing wireless around over 11% share and weaponry segment with almost coverage, remote sensing,