# Improved Road Segment-Based Geographical Routing Protocol for Vehicular Ad-hoc Networks
## 3 Improved Road Segment-Based Geographical Routing Protocol
### Routing Process, Flowchart and Algorithms
## 5 Conclusions and Future Work

In this paper, we investigated the existing routing protocol limitations and designed an efficient, stable, and robust routing protocol for VANETs. The existing routing protocols have suffered in terms of dis-connectivity, delay, lower throughput, packet drop, and delivery issues for urban areas due to network dynamics, unpredictable topologies, and the high mobility of nodes. A critical examination of these limitations led to the design of ISR based on traffic density, distance, and the direction of nodes for the next forwarder and route selection. ISR was simulated using a network simulator, and the performance of the protocol was compared with existing routing protocols. The simulation results showed that ISR had a higher data delivery ratio, a lower delay, a higher throughput, and less one-hop disconnections in the scenario of a growing number of vehicular nodes and increasing vehicle speed. The research work was carried out to find the solutions of the problems that were discussed in the literature review. It was found that research regarding beaconless geographical routing protocols still has a long way to go. In the future, we will work towards drone-enabled vehicular ad-hoc \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & & **PDR** & \multicolumn{4}{c}{**End-to-End Delay**} & \multicolumn{4}{c}{**Data Throughput**} & \multicolumn{4}{c}{**One Hop**} \\  & & ISR & VBRP & TASR & ISR & VBRP & TASR & ISR & VBRP & TASR & ISR & VBRP & TASR \\  & 0.63 & 0.5 & 0.53 & 0.1 & 0.4 & 0.5 & 350 & 335 & 330 & 5 & 8 & 8 \\  & 0.64 & 0.52 & 0.54 & 0.2 & 0.5 & 0.7 & 320 & 310 & 300 & 8 & 18 & 15 \\  & 0.65 & 0.56 & 0.55 & 0.5 & 0.6 & 1 & 300 & 280 & 270 & 12 & 27 & 25 \\  & 0.65 & 0.60 & 0.6 & 0.6 & 0.9 & 1.3 & 280 & 260 & 250 & 18 & 34 & 30 \\  & 0.66 & 0.62 & 0.62 & 0.8 & 1 & 1.5 & 240 & 220 & 210 & 22 & 40 & 35 \\  & 0.69 & 0.65 & 0.66 & 1 & 1.8 & 1.7 & 200 & 180 & 170 & 25 & 50 & 45 \\  & 0.72 & 0.70 & 0.64 & 1.5 & 2.6 & 2 & 160 & 120 & 100 & 30 & 70 & 60 \\  & 0.81 & 0.73 & 0.66 & 1.7 & 3 & 2.5 & 140 & 119 & 90 & 31 & 65 & 65 \\  & 0.86 & 0.75 & 0.69 & 2 & 3.2 & 2.9 & 120 & 117 & 80 & 32 & 60 & 70 \\ \hline  & 0.95 & 0.9 & 0.92 & 0.2 & 0.5 & 0.4 & 300 & 280 & 250 & 7 & 18 & 15 \\  & 0.94 & 0.88 & 0.90 & 0.4 & 0.6 & 0.5 & 250 & 220 & 200 & 10 & 28 & 20 \\  & 0.91 & 0.85 & 0.88 & 0.6 & 1 & 1.2 & 200 & 170 & 140 & 14 & 37 & 30 \\  & 0.88 & 0.8 & 0.85 & 0.9 & 1.3 & 2.2 & 150 & 120 & 100 & 18 & 44 & 35 \\  & 0.85 & 0.77 & 0.80 & 1 & 1.8 & 2.5 & 140 & 100 & 70 & 25 & 50 & 40 \\  & 0.77 & 0.70 & 0.75 & 1.2 & 2.2 & 3 & 130 & 80 & 55 & 30 & 60 & 50 \\  & 0.72 & 0.65 & 0.70 & 1.8 & 2.5 & 3.3 & 120 & 60 & 40 & 35 & 75 & 65 \\  & 0.68 & 0.60 & 0.65 & 2.2 & 3.1 & 3.5 & 110 & 50 & 35 & 33 & 70 & 70 \\  & 0.66 & 0.50 & 0.55 & 2.9 & 4 & 3.7 & 100 & 40 & 30 & 30 & 65 & 75 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Analysis of the packet delivery ratio (PDR), delay, throughput, and one hop disconnection. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Protocols**} & \multicolumn{3}{c}{**Performance of ISR against Benchmark Protocols**} \\ \hline
**ISR** & **PDR** & \multicolumn{2}{c}{**End-to-End Delay**} & \multicolumn{2}{c}{**Throughput**} & \multicolumn{2}{c}{**One Hop**} \\  & & **Delay** & \multicolumn{2}{c}{**Disconnection**} \\ \hline With number of nodes & 0.68 \% \(\uparrow\) & 5.6\%\(\downarrow\) & 16\%\(\uparrow\) & 18\%\(\downarrow\) \\ With Vehicle Speed & 71\%\(\uparrow\) & 5.8\%\(\downarrow\) & 38\%\(\uparrow\) & 24\%\(\downarrow\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Performance of ISR against competitive protocols with increasing \(\uparrow\) or decreasing \(\downarrow\) trend. networks to enhance the routing and traffic services in real-time traffic environments. How the drone communication framework could benefit on road vehicular traffic information dissemination will be another quest of our future research [28]. Conceptualization, K.N.Q. ; formal analysis, F.U.I. ; investigation, F.U.I. ; methodology, F.U.I.