Unmanned-Aerial-Vehicle-Assisted Wireless Networks: Advancements, Challenges, and Solutions

The rapid development of communication and computing techniques enables unmanned aerial vehicles (UAVs) to provide reliable and cost-effective wireless communication and computing services from the air. Compared to the conventional fixed infrastructure, UAVs have attractive attributes, such as high flexibility and operability, and, as a result, on-demand line-of-sight connection links. Therefore, UAV-assisted wireless networks have been envisioned as a promising paradigm to achieve enhanced coverage and connectivity for future wireless communications. Meanwhile, achieving high levels of energy efficiency, sensing, communication, and computing capacities, and security and privacy are critical to the success of UAV-assisted wireless networks. In order to improve the performance of UAV-assisted wireless networks, some frameworks and mechanisms have been developed in the past few years. In this article, we provide a comprehensive survey of these developments. Specifically, we conduct a brief overview for the architecture of UAV-assisted wireless networks from four domains (i.e., framework-related, technology-related, challenge-related, and solution-related) and four aspects (i.e., sensing-related, communication-related, computing-related, and application-related). Then, the integrated sensing, communication, and computing for UAV-assisted wireless networks is introduced, followed by the characteristics and requirements. We also provide the implementation and applications of UAV-assisted wireless networks. Next, we discuss the challenges and the state-of-the-art solutions for UAV-assisted wireless networks. Finally, the advanced technologies for UAV-assisted communication and computing networks are exploited, followed by the potential research directions.

I. Introduction

With the prosperity of mobile networks and the evolution toward beyond 5G (B5G), more and more services focus on the application of unmanned areas. In particular, unmanned aerial vehicles (UAVs) have attracted much attention due to their high mobility and suitability for flexible deployment, which allow UAVs to play the role of communication infrastructure on the move, and have been expected to be an important complementary part of future wireless communication networks. Therefore, as an extension of terrestrial networks, diverse UAVs have rapidly been deployed for different activities, thus enabling the paradigm of UAV-assisted wireless networks which have been envisioned as one of the efficient paradigms for providing high throughput and extensive access schemes for massive wireless terminals [1]. For instance, UAVs are widely used in diverse fields for different purposes. In scenarios of high traffic demand and heavy network load, UAVs can be deployed as the aerial communication platforms for providing ubiquitous accessing and communication services for ground devices [2]. Moreover, in comparison with the stationary terrestrial infrastructure, the high flexibility enables UAVs to enhance the connectivity and service capacities [3]. For instance, to support on-demand data relay and delivery, UAVs can be deployed as the aerial base stations (BSs) in a dynamic manner. Furthermore, owing to the Line-of-Sight (LoS) links, a swarm of UAVs can form a flying ad-hoc network (FANET) with coordination and collaboration to serve ground devices, such as sensing, communication, and computing services. Therefore, as the desirable candidate to increase the coverage of the terrestrial networks, the integration of UAVs with wireless networks can lead to numerous applications [4].