## 4 Performance Evaluation
### QoE Parameters  
The simulation results show that the GeoQoE-Vanet protocol performs better than GPSR and GPSR-2P protocols. The received video quality at the destination has increased with the number of vehicles. This results from the flow of transmitted video data being shared between more vehicles as shown in Figure 8 and Table 5. Figure 8 represents the mean PNSR of results of all scenarios. Table 5 illustrates the mean \(MOS_{video}\) of results of all scenarios. The proposed protocol can find better-relaying vehicles which allows it getting high \(MOS_{video}\) values. \(MOS_{video}\) for GPSR and GPSR-2P is less than GeoQoE-Vanet because they can not avoid bad relaying vehicles. Their next-hop selection mechanism is based only on distance. When the number of vehicles is decreased, the \(MOS_{video}\) is decreased also because alternatives here become limited and the load is shared between a limited number of vehicles. This may lead to congestion that induces packet loss, delay, and jitter which degrades the quality of the received video. In all scenarios, GeoQoE-Vanet gives the best results because it adapts well to the network degradation and always select the best vehicles based on their quality factors and not only on their distance from the destination. \begin{table}
\begin{tabular}{c c} \hline \hline
**PSNR (dB)** & **MOS** \\ \hline \(\geq\)37 & 5 (excellent) \\
31–36.9 & 4 (good) \\
25–30.9 & 3 (fair) \\
20–24.9 & 2 (poor) \\ \(\leq\)19.9 & 1 (bad) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: PSNR to MOS conversion [58]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Protocol**} & \multicolumn{5}{c}{\(MOS_{video}\)} \\ \cline{2-5}  & **10** & **20** & **30** & **40** & **45** \\  & **Vehicles** & **Vehicles** & **Vehicles** & **Vehicles** & **Vehicles** \\ \hline GeoQoE-Vanet & 2 & 2 & 3 & 3 & 4 \\ GPSR-2P & 1 & 1 & 2 & 3 & 3 \\ GPSR & 1 & 2 & 3 & 3 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: End-user mean \(MOS_{video}\) of received video in all scenarios. The results shown in Figure 8 and Table 5 are confirmed by SSIM results in Figure 9. Figure 9 represents the mean SSIM of results of all scenarios. The quality improves with the increasing number of vehicles and reaches the maximum of 0.904 for GeoQoE-Vanet in the scenario of 45 vehicles. The SSIM diminishes when the number of vehicles decreases. However, in all scenarios, the SSIM of GeoQoE-Vanet is always better than that of GPSR and GPSR-2P. Figure 10 illustrates an example of the quality of received frames in one scenario of 40 vehicles. At the beginning of the simulation, the quality of the received frames is low. After a short period of time, a fast increase in the quality of received frames appears because the number of the received packets increases. There are a small packet loss and jitter which are the result of limited number of transmitted video packets. The shown decrease and increase at the beginning are the effect of initial delay which does not have a significant impact on the rest of the simulation. The quality decreases again over time because packet loss and jitter occur when transmitted data between vehicles increases. The proposed protocol preserves a good quality of frames because it selects the vehicles that ensure the best quality. GPSR and GPSR-2P have a remarkable quality degradation because the relay vehicles selection is based only on distance from the destination and do not allow avoiding vehicles that can not ensure quality. At the end of the video transmission, there is a decrease in the quality of frames. This is due to increased packets loss and jitter when the number of transmitted packets is high. It is shown in Figure 10 that GPSR and GPSR-2P have a high number of lost frames and the proposed protocol performs better. Figure 11 illustrates the results of SSIM of one scenario of 40 vehicles and confirms the results in Figure 10. It shows a decrease in quality of received frames at the beginning of the simulation followed by a rapid increase.