# Seamless Handover Scheme for MEC/SDN-Based Vehicular Networks
## 5 Performance Evaluation
### Simulation Results
The percentage of blocked tasks increased with the increase in traffic density in all three systems; however, the developed scheme achieved a higher efficiency in terms of blocked tasks. The developed MEC/SDN-based handover scheme achieved an average percentage improvement in the number of blocked tasks of 51% compared to the first system. Thus, the introduction of MEC in the handover scheme achieved a higher efficiency in terms of blocked tasks, due to the implementation of the handover scheme near to the end user, with less overhead. Moreover, the deployment of SDN with MEC facilitated the operation of the MEC during the handover implementation and the maintenance of the TCP connection. The third performance metric was the percentage of failed handover processes compared to the total number of requested handover processes. Figures 11-13 provide the records of the handover failure rate for the developed handover scheme and the traditional schemes. These results were for different velocities, traffic densities, and numbers of deployed vehicles. Figure 11 provides the handover failure rate for the two systems at different traffic densities. These results were for a VANET with 400 vehicles and a vehicle velocity of 50 Km/h. The developed scheme achieved better efficiency in performing the \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Figure**} & \multicolumn{2}{c}{**System (1)**} & \multicolumn{2}{c}{**System (2)**} & \multicolumn{2}{c}{**System (3)**} \\ \cline{2-7}  & **Standard Deviation** & **Mean** & **Standard Deviation** & **Mean** & **Standard Deviation** & **Mean** \\ \hline Figure 8 & 5.29 & 49.00 & 9.02 & 18.33 & 3.00 & 5.00 \\ Figure 9 & 15.13 & 54.00 & 13.41 & 22.83 & 6.79 & 7.83 \\ Figure 10 & 8.54 & 59.00 & 5.13 & 23.33 & 3.06 & 7.67 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Statistical analysis of simulation results of the three systems introduced in Figures 8–10. Figure 10: Percentage of blocked tasks for the three systems at different traffic densities. and a seamless handover scheme for said structure. The handover process is implemented by an MEC server connected to an RSU, when vehicles come to the intersection of two coverage regions of neighboring RSUs. The developed scheme is based on three calculated threshold levels of received signal power in a way that ensures the handover process is performed before the received signal decreases below the reference threshold level that affects the packet reception. The developed scheme achieved a percentage improvement in the PDR of 64% compared to the existing traditional scheme. Moreover, the developed VANET achieved a 51% percentage improvement in blocked computing tasks compared to existing systems. The handover failure rate of the developed handover scheme was lower than the existing scheme by an average of 18%. Our future directions for this work include analyzing and modifying the algorithm for crossroads with overlapped coverage results from multiple RSUs. This includes adding more metrics, such as the RSU load and the vehicle's predicted direction. Conceptualization, M.M.T., N.M. and A.A.A. ; methodology, A.V. and F.E.A.E.-S.; software, M.M.T., A.M., N.M. and A.A.A. ; validation, A.V., M.A.T., and A.A.A.A. ; formal analysis, M.M.T. and N.M.; investigation, A.M. and A.V. ; resources, F.E.A.E.-S.; data curation, M.A.T. ; writing--original draft preparation, M.M.T., N.M. and A.A.A. ; writing--review and editing, F.E.A.E.-S. and A.M.; visualization, A.M.; supervision, F.E.A.E.-S.; project administration, A.A.A. ; funding acquisition, A.V. All authors have read and agreed to the published version of the manuscript. Research funded by the Ministry of Digital Development, Communications, and Mass Media of the Russian Federation, contract number \(\Pi\)33-1-26/9 (Moscow, Russia). Not applicable. The data presented in this study are available on request from the corresponding author. The researcher [PERSON] is funded by the Ministry of Higher Education of the Arab Republic of Egypt.