## 1 Introduction  
During the past couple of years, providing access anytime and anywhere to network resources has become an important challenge for FANET. Such a challenge is further agitated in mission-critical applications such as disaster recovery operations, where on-time data transmission is a prerequisite. Therefore, there exists a high demand for wireless communication technologies that can be rapidly deployed to enable data communication services with air-to-air and air-to-ground links. One possible solution for providing wireless connectivity is via high-altitude platforms (HAPs), such as balloons. The balloons generally reside on stratosphere at an altitude of about tens of kilometers above the earth's surface, as shown in Figure 1. However, HAP-based communications are preferred for large geographical areas. On the other hand, low-altitude platforms (LAPs) have several advantages over HAPs [1], primarily in cases of disastrous events when existing communication infrastructure collapses and where it is difficult to install communication infrastructure in a short amount of time. These on-demand short-range wireless technologies can be used to provide easily deployable and reconfigurable communication services for connecting UAVs with rescue teams on the ground. Moreover, due to the low altitude of UAVs, short-range wireless links lead to substantial performance improvement over the high-altitude wireless links. In addition, performance can further be improved with jointly designed adaptive communications with a UAV mobility model. For example, when a UAV experiences good communication channel with the ground station, the speed to sustain wireless connectivity is reduced. These evident benefits make a short-range wireless system a promising solution for the low-cost deployment of the future flying ad-hoc network. Recently, the need for various types of on-demand wireless communication technologies is increasing for the rapid, efficient, and low-cost deployment of FANET. The technology of choice should be able to support air-to-air and air-to-ground connections in an unhampered manner. It must be able to cater to a wide range of UAV applications, irrespective of significant height and orientation differences of UAVs [2]. In this context, a number of wireless technologies can be exploited for FANET, in order to execute the communication compulsion for all UAV applications. However, a pertinent question needs to be answered about the existing wireless technologies, which is whether they are able to withstand the harsh environment of aerial links or not. Secondly, the doubt behind their applicability for the real-time communication also needs to be cleared. One of the major purposes of our work is to come forth with answers to the requirements, constraints, and shortcomings of these technologies for FANET-focused communication and networking schemes. Since wireless communication technologies are progressing at a rapid pace, UAVs with reduced size are being introduced with increased incorporation in FANET applications. Thus, the installation and maintenance of the networked communication among multiple UAVs and the ground station has emerged as a crucial task [3]. In addition, accomplishing the complex tasks, the UAVs need to assure simultaneous coordination with each other and with the ground station. For this reason, to realize a well-coordinated UAV ad-hoc network, an efficient architecture is required [4]. Inspired by the aforementioned observations, in this work, with the aim to address the communication and networking needs of FANET, we present a comprehensive review of  
Figure 1: High-altitude platform (HAP) for FANET. communication architectures and wireless technologies. It has been concluded that multi-layer UAV ad-hoc network is the most suitable architecture for networking a group of heterogeneous UAVs, while 802.15.1 is the strongest candidate in short-range wireless technologies.