## 5 Comparison of Topology Based Routing Protocol  
This section comprehensively compares the key characteristics, routing approach, mobility models, simulation methodology, performance metrics, and application scenario of conventional and newer topology-based routing protocols. Table 3 identifies the major features of existing topology-based routing protocols, and Table 4 compares the characteristics of the different routing protocols.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Protocol Type** & **Protocol Name** & **Reference** & **Main Feature** \\ \hline \multirow{6}{*}{**Proactive**} & OLSR & Ref. [95] & MPRs technique and use link quality extension \\ \cline{2-4}  & P-OLSR & Ref. [93] & Fast response to Network topology changes \\ \cline{2-4}  & ML-OLSR & Ref. [92] & Reduce the time required for MPRs selection and path disconnections \\ \cline{2-4}  & GPNC-SP & Ref. [89] & Reduce the overhead in the network \\ \cline{2-4}  & OLSR-ETX & Ref. [90] & Support high-mobility networks \\ \cline{2-4}  & TOLSR & Ref. [91] & Improve image quality during transmission in FANETs \\ \cline{2-4}  & QTAR & Ref. [94] & Considers two-hop neighbor nodes while making routing decisions, broadening the local perspective of the network architecture. \\ \hline \multirow{6}{*}{**Reactive**} & AODV & Ref. [102] & Utilize network bandwidth efficiently \\ \cline{2-4}  & ADRP & Ref. [101] & Optimize messages of route discovery based on probability of adaptive forward \\ \cline{2-4}  & RM-AODV & Ref. [97] & Suitable for video surveillance and can handle an increase in bandwidth \\ \cline{2-4}  & BR-AODV & Ref. [98] & Suitable for surveillance mission and forest fire \\ \cline{2-4}  & SARP & Ref. [96] & Reduce the rebroadcasting of control message of route request \\ \cline{2-4}  & EE-Hello & Ref. [99] & Enhanced routing process by reducing the number of hello messages \\ \cline{2-4}  & MDRMA & Ref. [100] & Provide a new routing mechanism by controlling the date rate with respect to the mobility of UAVs \\ \hline \multirow{6}{*}{**Hybrid**} & ZRP & Ref. [107] & Enhance the efficiency of route query and reply for reactive nature \\ \cline{2-4}  & SHARP & Ref. [106] & Reduce the number of zones to decrease the overhead \\ \cline{2-4}  & RTORA & Ref. [105] & Support several routing techniques and loop-free \\ \cline{2-4}  & LERP & Ref. [104] & Support breakages in low link \\ \cline{2-4}  & RFLSR & Ref. [103] & Enhance energy efficiency based on link-state routing \\ \hline \multirow{3}{*}{**Static**} & LCAD & Ref. [110] & Enhance routing security and achieve maximum throughput \\ \cline{2-4}  & MLHR & Ref. [108] & Suitable for large FANETs \\ \cline{2-4}  & DCR & Ref. [109] & Transmit data from one UAV to many UAVs in FANETs \\ \hline \hline \end{tabular}
\end{table}
Table 3: Main features of topology-based routing protocols.  
Table 3 lists the unique creative characteristics of each of the 22 studied topology-based routing protocols for FANETs. According to our findings, proactive and reactive routing techniques perform better in highly dynamic FANETs than other protocols do. Furthermore, mostly under the monitoring application, hybrid protocols are appropriate for large-scale FANETs.