# Moving Ad Hoc Networks--A Comparative Study
## 4 Flying Ad-Hoc Network (FANET)  
One of the key application cases of UAVs is the use of FANET, which is a subset of VANET [32, 33]. In the FANET, coordination and collaboration between nodes are very important for effective data transmission [34, 35, 36]. The collaboration between nodes depends on the node behavior, and the concept of trust can be used to quantify the node behavior [37, 38, 39]. Trust helps isolate non-cooperative and malicious network nodes, thereby improving the reliability of the information exchange between nodes [40, 41, 42]. For networks with highly mobile devices, routing protocols are not practical or do not provide enough throughputs in VANET. However, the topology of the FANET alternates more frequently than that of VANET or MANET [43, 44]. The most essential network technology which is applicable these days for the implementation of FANETs is the IEEE 802.11a and 802.11s for mesh ad hoc network extension. A jet powers a flying ad hoc network or a reciprocating engine, and it is piloted remotely through pre-programmed flight plans. These are also called Unmanned Aerial Vehicles (UAVs) and are mostly used for military operations [45, 46]. This aerial vehicle works without human help and does not carry humans onboard, like autopilot. The communication in FANET is broadly classified as UAV-to-UAV (U2U) and UAV-Infrastructure communications (U2I), as shown in Figure 9. In the FANETs, the nodes communicate with each other using multi-hop communication, where one node is linked or connected to the infrastructure and the rest has multi-hop communication [47, 48]. Therefore, it is not necessary that all UAV flights should communicate to the satellite or ground base station [49, 50, 51, 52, 53]. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Reference** & **Major Contribution** & **Year** \\ \hline
[19] & A comprehensive overview of the resource allocation approach for VANETs, as well as challenges and opportunities. & 2021 \\ \hline
[20] & A Comparative Survey of Reinforcement Learning-based VANET & 2021 \\  & routing algorithms & \\ \hline
[21] & A comprehensive survey in the security of vehicular ad hoc networks, trust management, arracks, and security mechanisms. & 2020 \\ \hline
[22] & A comprehensive Survey of Privacy Schemes and Authentication to different types of attacks in vehicular ad hoc Networks & 2020 \\ \hline
[23] & A Survey of the inadequacies of existing trust and weaknesses establishment, management mechanisms, and some future challenges for trustworthy communication in VANET & 2020 \\ \hline VANET & [24] & A survey on the different authentication mechanisms and possible security attacks in VANETs & 2020 \\ \hline
[25] & Exhaustive review based on wireless communication, Benefits, Recent Works, Security, Services, Challenges, and Use Cases for SDN-VANET & 2020 \\ \hline
[26] & A survey of vehicular edge computing for architecture, mobility, applications, and research directions & 2019 \\ \hline
[27] & Authentication schemes, privacy, security, architecture, and open challenges, in VANET & 2021 \\ \hline
[28] & A Survey of Security Services, Attacks, and Applications for Vehicular Ad Hoc Networks & 2019 \\ \hline
[29] & Communication, security and privacy, applications, and challenges in VANET & 2019 \\ \hline
[30] & Architecture, security classification and solutions, challenges, and various simulators in VANET & 2019 \\ \hline
[31] & A survey on Multi-Layer Problems and Solutions in VANETs & 2019 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of the existing surveys in VANET. * Challenges in UAV Communications:
* Geographical and environmental constraints,
* Mobility of the node,
* Sufficient bandwidth availability and low latency,
* Synchronization between the UAVs swarms. * Advantages of using multi-UAV over single UAV:
* Cost: Many interviewees said that using drones to collect data is not difficult, but the real problem and challenge is how to use the massive amounts of data collected.