A Review of Flying Ad Hoc Networks: Key Characteristics, Applications, and Wireless Technologies

Round 1

Reviewer 1 Report

This paper presented a comprehensive review of FANETs, highlighting FANETs characteristics, routing protocols, and new applications. The main objective of this review is to provide a thorough overview of overall research in the area of FANETs, describing the different types of UAVs used in FANETs, their main characteristics, and their applications.

In section 5, we only see the classification, but we don't know how to select different protocols in different scenarios.

The same above problem is also in section 6 and section 7.

So I think the pros and cons of the different routing protocols, mobility models, and integrated technologies should be analyzed.  And should be shown in Fig.6, 7, and table 2.

Author Response

Thanks for your comments, the following changes have been applied in the paper in blue.

Section 5:
Selecting the best routing protocol for UAV-based scenarios depends on different characteristics, including routing approach (dynamic, static, On-demand, and hybrid), mobility models, simulation tools, and performance metrics. Although UAV routing protocols are still in the early stages of
development, reactive and proactive routing approaches perform better in highly dynamic FANETs than other protocols do. In addition to this, hybrid protocols are better to employ in monitoring applications for
large-scale FANETs \cite{drones6010009}.

Section 6:
There are several parameters, including the altitude, path and direction of flying, and atmospheric conditions that impact UAVs' mobility.
In addition to these parameters, other important aspects should be considered to select each mobility model of the UAV in different scenarios. These
aspects include the avoidance of connections that control the distance between UAVs, controlling the sudden change of UAV's direction and the safety standards and deployment are should be considered in
order to prevent collision between UAVs \cite{drones6010009}.

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper presented a comprehensive review of Flying Adhoc Networks, highlighting FANETs characteristics, routing protocols, etc. The reviewer found that the current paper itself contained sufficient information for publication, except that the main contribution of the paper is vague to the reviewer (knowing that if it is a survey paper, it is fine since the authors have attempted to summarize latest works). As one recommendation for changes of the paper to furthermore emphasize its true contribution, a new section discussing the future prospects including technology challenges should be added following Sect. 8 of the current paper.

Author Response

Thanks for your comments, the following changes have been applied in the paper in orange.

\section{Future prospects }
\label{sec:future_pros}
Although collaborative UAVs technologies discussed in Section \ref{sec:FANETs_technologies}, bring a number of benefits for several collaborative applications, there are a number of challenges that should be
addressed \cite{6842275}.
Due to the energy limitations of UAVs, energy-efficient algorithms should be designed for different aspects such as collaborative communication, sensing, processing, acting and data storage in these technologies
\cite{6842275}. Providing efficient resource management strategies that try to manage dynamically various resources such as bandwidth, transmit power, the number of UAVs, and UAV’s flight time, is another challenging issue in UAV-assisted technologies \cite{8660516}.
Security provision in UAV-based communication is a complex task, as UAVs are being widely used in technologies for domains (military, rescue services, and infrastructure inspection) that involve sensitive information. Therefore, efficient techniques are required to provide reliable and secure communication
and services in the technologies associated with UAVs \cite{6842275, s18114015}. As future work, we plan to apply an artificial Immune system-based Danger Theory to enhance FANET security since we have found promising results in \cite{JIM2022102538}.In addition, the flexible deployment of a UAV relies on its mobility to fly towards the destination and
perform its mission. To prevent conflict and manage the level of the battery, UAVs’ real-time mobility reactions and states are vital in discussed technologies \cite{9464915,8397657}.

 

Conclusion:

\item \textit{\textcolor{orange}{Future Directions}}: \textcolor{orange}{When it comes to using new technologies integrated with UAV-based communication, open challenges such as energy limitations of UAVs, managing dynamically 
various resources such as bandwidth, transmit power, the number of UAVs, and UAV’s  flight time, the FANET security should be addressed.}

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors of this article provide a survey on drones or unmanned aerial vehicles (UAVs) employed in flying ad hoc networks (FANETs) as well as a review of current/upcoming technologies that integrate with FANETs. The paper provides a thorough taxonomy of UAVs; moreover, an extensive characterization of FANETs is supplied along with routing protocols and mobility models considered therein.

The article starts with a classification of UAVs according to a set of parameters including their size, weight, range and endurance, altitude, flying mechanism, airspace class, degree of autonomy, ownership, engine, and applications. Particularly, the range of applications discussed is interesting and the authors supply a set of URLs providing up-to-date information about them. On the other hand, the authors also discuss the main parameters of FANETs followed by their applications and routing protocols.

Section 6, which presents UAV mobility models is extremely short and could be easily enriched. One subject that is not discussed in this survey is the availability of simulators for FANETs. The paper seems to be mainly focused on their classification, thus lacking an important discussion of the availability of tools for analyzing and studying FANETs. Therefore, it is strongly suggested the authors consider adding a section studying such a subject.

The paper is well structured and flows well. Moreover, it is well written. The authors start the Introduction section by including Figure 1, which depicts the article's structure. Such a figure can be freely avoided. The list of references is vast and should be enriched with a list of contributions about simulators for FANETs once the authors include such a section.

Author Response

Thanks for your comments, Figure 1 was removed and the following changes have been applied in the paper in red.

 

Section 6:
\section{Simulation Tools}
\label{sec:Simu_tool}
Evaluating the performance of UAV-based communication networks in the real world is a tough task that requires remarkable time and resources. Frequent topology changes and the high degree mobility of the UAVs in FANETs make the practical evaluation of UAV performance a challenging, costly, and time-consuming task. In addition, due to some regulations of using
UAVs in most countries, some cyber-attack resistance evaluation tests for UAV networks are not allowed \cite{CHRIKI2019106877}.
Therefore, many flexible simulation tools, frameworks, emulators, and testbeds have been developed to make it possible to create, implement, test, and evaluate schemes virtually without requiring real-world implementation.The available FANETs performances analysis tools includes \textit{AVENS, CUSCUS, Simbeeotic, UAVSim, UTSim, FANETSim, Netsim, OMNeT++, NS2,NS3, OPNET, ROS-NetSim, MATLAB, TOSSIM, QualNet, GloMoSim, YANS, ONE, SSFNet, FlynetSim, J-Sim,BonnMotion, GAZEBO, AirSim, RoboNetSim, Mininet-Wifi } and \textit{SUMO}, each of them support different mobility models, operating system, and programming languages \cite{9438449}, \cite{9491882}, \cite{doi:10.1177/1550147716664740}, \cite{8450505} .

 

Conclusion:

\item \textit{\textcolor{red}{Simulation Tools:}}
\textcolor{red}{The available  FANETs performances analysis tools includes \textit{AVENS, CUSCUS, Simbeeotic, UAVSim, UTSim, FANETSim, Netsim, OMNeT++,  NS2,NS3, OPNET, ROS-NetSim, MATLAB, TOSSIM, QualNet, GloMoSim, YANS, ONE, SSFNet, FlynetSim, J-Sim, BonnMotion, GAZEBO, AirSim, RoboNetSim, Mininet-Wifi } and \textit{SUMO}, each of them support different mobility models, operating system, and programming languages}
\item \textit{\textcolor{orange}{Future Directions}}:

Author Response File: Author Response.pdf

Reviewer 4 Report

This paper presents a review on Flying Ad Hoc Networks.  I found it generally quite clear and easy to read. 

Some small questions remain which should be clarified.

For example, Section IX is missing in Figure 1.

In Table 1, the column "Altitude" should read "Maximum Altitude".

There were a few small spelling and grammatical errors listed below:

1. Line 2 - "(UAVs) (or drones) made them" should read "(UAVs), or drones, have made them"

2. Line 36 - "the FANETs'" should read "FANETs'"

3. Line 164 - "within per unit area" should read "per unit volume"

4. Line 170 - "UAVs that causes" should read "UAVs.  This causes"

5. Line 173 - "high movements" should read "rapid movements"

6. Line 207 - "in FANET" should read "in FANETs"

7. Line 369 - "As Figure Figure 7" should read "As Figure 7"

8. Line 424 - "can operate in" should read "can perform"

9. Line 496 - "disscussion on possible" should read "discussion of possible"

If these minor errors are fixed, I believe this article should be considered for publication.

 

Author Response

Thanks for your comments.

Some small questions remain which should be clarified.
For example, Section IX is missing in Figure 1. Revised!
In Table 1, the column "Altitude" should read "Maximum Altitude". Revised!
There were a few small spelling and grammatical errors listed below:
1. Line 2 - "(UAVs) (or drones) made them" should read "(UAVs), or drones, have made them" Revised!
2. Line 36 - "the FANETs'" should read "FANETs'" Revised!
3. Line 164 - "within per unit area" should read "per unit volume" Revised!
4. Line 170 - "UAVs that causes" should read "UAVs. This causes" Revised!
5. Line 173 - "high movements" should read "rapid movements" Revised!
6. Line 207 - "in FANET" should read "in FANETs" Revised!
7. Line 369 - "As Figure Figure 7" should read "As Figure 7" Revised!
8. Line 424 - "can operate in" should read "can perform" Revised!
9. Line 496 - "discussion of possible" should read "discussion of possible" Revised!

Round 2

Reviewer 1 Report

The paper has been revised according to my comments, and I think it is more clearer to read for the interested researchers. 

Author Response

Dear Reviewer,

Thank you very much for your comment.

 

Reviewer 3 Report

The authors added a (very short) Section 9, listing a set of simulation frameworks potentially useful for studying the performance of FANETs. In the list, the NS-2 simulator is included, which is a bit surprising. How NS-2 can be used to simulate FANETs given that it provides very limited support for IEEE 802.11 amendments?

I am sure the authors might provide an improved Section 9, rather than just mentioning a list of simulators that could be used to simulate FANETs.

Author Response

Dear Reviewer,

Thanks for your comment.

Section 9, was revised by adding Table 2, describing each simulation tool.

Regarding NS2, based on my reading, it supports some mobility models such as RW, RWP,  GM, MG, RPGM.  It is a discrete event simulator used for networking research which simulates TCP, routing, and multicast protocols over wired and wireless (local and satellite) networks. 

If you think it is not included in this section, please let me know, so I can remove it.

 

Author Response File: Author Response.pdf