This survey studies the potential data link candidates for unmanned aircraft vehicles (UAVs). There has been tremendous growth in different applications of UAVs such as lifesaving and rescue missions, commercial use, recreations, etc. Unlike the traditional wireless communications, the data links for these systems do not have any general standardized framework yet to ensure safe co-existence of UAVs with other flying vehicles. This motivated us to provide a comprehensive survey of potential data link technologies available for UAVs. Our goal is to study the current trends and available candidates and carry out a comprehensive comparison among them. The contribution of this survey is to highlight the strength and weakness of the current data link options and their suitability to satisfy the UAVs communication requirements. Satellite links, cellular technologies, Wi-Fi and several similar wireless technologies are studied thoroughly in this paper. We also focus on several available promising standards that can be modified for these data links. Then, we discuss standard-related organizations that are working actively in the area of civilian unmanned systems. Finally, we bring up some future challenges in this area with several potential solutions to motivate further research work. Index Terms-Unmanned aircraft systems (UAS), unmanned aircraft vehicle (UAV), civilian applications, data link, satellite communication, cellular communication, aviation standards, standard bodies, future challenges. SATCOM Provider ATC Pilot Cellular Provider Satellite UAV Cellular Tower Fig. 1 2
2) Network RequirementsThere are several survey papers discussing the requirements for UAS data link such as [2], and [9][10][11][12][13][14]. For example, the requirements for the UASs based on four different areas of missions, communication networks, communication data links, navigation, and surveillance are discussed in [2]. Several detailed discussions about the communication data link requirements such as range, velocity, latency, reliability, availability, integrity, security, and bit rate are provided. As another instance, a survey of UAVs communication requirements has been studied in [9]. These requirements are based on four categories of UAV applications (i.e., search and rescue, area coverage, delivery/transportation, and construction). Moreover, the important requirements and considerations regarding the network layer of UAV communications have been discussed in [14].
3) Channel ModelingChannel modeling must be studied for designing and evaluating proper UAV data links for different applications. There have been several research work and surveys on channel modeling for UAV communications, such as [15][16][17][18]. For instance, a comprehensive survey on channel modeling for UAV communications is provided in [15]. Different channel modeling approaches along with the associated challenges have been studied.
4) Our ContributionWe have studied the existing survey papers on the aforementioned issues related to the UAV data links. In this s...