## 4 Privacy-Preserving Optimization Based on Advanced CH Selection (P2O-ACH)
### Enhanced ROA-Based CH Selection
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**S. No** & **GWO-CH** & **ACO-SCRS** &
\begin{tabular}{c} **QMM-** \\ **VANET** \\ \end{tabular} & **P2O-ACH** \\ \hline Packet Loss & 1578 Packets & 1248 Packets & 867 Packets & 458 Packets \\ Network Lifetime & 65.22\% & 71.86\% & 85.47\% & 97.46\% \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Performance Values of Packet Loss and Lifetime Calculation of the Network. Figure 5: Network Lifetime Calculation. Figure 6: Packet Delivery Ratio Calculation. The values stated in Table 7 prove that the packet delivery ratio achieved by the proposed P2O-ACH is better than earlier works where the packet delivery ratio of the P2O-ACH is 95.13% and the packet delivery ratios of the GWO-CH, ACO-SCRS, and QMM-VANET are 75.12%, 81.28%, and 89.46%, respectively. This is achieved because the privacy-preserving mobility pattern provides security during the process of vehicles joining and leaving the cluster, which reduces the loss of packets, and automatically increases the packet delivery ratio. Then, the latency of the proposed P2O-ACH is lower than earlier works where the latency of the P2O-ACH is 253.79 ms and the latencies of the GWO-CH, ACO-SCRS, and QMM-VANET are 681.92 ms, 546.23 ms, and 502.48 ms, respectively. The network is constructed stably so as to reduce the latency. Due to the advanced clustering method, the communication is highly standardized, which reduced the latency in the network. In Figure 8, the routing overhead is calculated and in the comparative graph the values of all the methods are shown. The main aim of the research is to reduce the energy consumption and overhead of the network. From the results, it is understood that the overhead produced by the proposed P2O-ACH is very much lower than that of the other works. This is because the privacy-preserving mobility pattern generation measures each action of the clusters, such as vehicle migration and fusion. Additionally, hash-based security is provided in it. So, the traffic pattern is secured and stable, which reflects in the overhead. In Figure 9, network throughput is calculated and the throughput achieved by the proposed P2O-ACH is higher than the earlier works. The parameters, such as latency and overhead, are comparatively low in the proposed P2O-ACH method. That is the main reason to achieve high throughput in the network. The values stated in Table 8 prove that the routing overhead achieved by the proposed P2O-ACH is low when compared with the earlier works where the overhead of the P2O-ACH is 2547 packets and the overheads of the GWO-CH, ACO-SCRS, and QMM-VANET are 7658 packets, 5967 packets, and 3467 packets, respectively. This performance is achieved mainly using the idea of CH selection that makes the network more reliable during the \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**S. No** & **GWO-CH** & **ACO-SCRS** &
\begin{tabular}{c} **QMM-** \\ **VANET** \\ \end{tabular} & **P2O-ACH** \\ \hline Packet Delivery Ratio & 75.12\% & 81.28\% & 89.46\% & 95.13\% \\ Latency & 681.92 ms & 546.23 ms & 502.48 ms & 253.79 ms \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Performance Values of Packet Delivery Ratio and Latency Calculation of the Network. Figure 7: Latency Calculation. process of communication. Hence, VANETs are networks with huge mobility. The mobility pattern is properly scheduled so that the overhead should be low. Then, the throughput achieved by the proposed P2O-ACH is higher than earlier works where the throughput of the P2O-ACH is 1047.467 Kbps and the throughputs of the GWO-CH, ACO-SCRS, and QMM-VANET are 301.124 Kbps, 457.128 Kbps, and 857.845 Kbps, respectively. Lowering the network overhead increases the throughput of the network. In the proposed P2O-ACH method, around 1000 packets to 5000 packets are comparatively saved from overhead, which reflects in the increase of throughput from 200 Kbps to 500 Kbps.