## 4 Proposed Protocol
### Vehicle Clustering and Monitoring  
One certification authority (CA) in a VANET authenticates all the vehicles within a 400 m cluster. The cluster may include 100 m range sub-clusters as per the topology of the VANET. The CA is a trusted third party that manages registration, authentication, and vehicle communication record registers. The vehicles moving on the highway are divided into several clusters. Each cluster has one Cluster Head (CH) and one or more cluster members. The cluster has two bands, each with one or more lanes. All the vehicles inside \begin{table}
\begin{tabular}{l l} \hline \hline
**Vehicle** & **CA Server** \\ \hline V2I Communication: & \\ Computes & \\ \(ID_{i}\) & \\ \(REF_{i}\) & \\ \(CL_{i}=(lat+long)\) & \\ \(LUI_{i}\) & \\ \(t_{i}\) & \\ \(\xrightarrow{\{ID_{i},REE_{i},CL_{i},LUI_{i},t_{i}\}}\) & \\  & \\  & \\  & \\  & \\  & \\  & \\ Parsing \(\{lat,long\}\) & \(\xleftarrow{\{lat,long\}\}\) & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: V2I Communication phase. \begin{table}
\begin{tabular}{l l} \hline \hline Vehicle A & Vehicle B \\ \hline V2V Communication: & \\ Selects \(ID_{rcv}\), \(MT_{i}\) and \(MP_{i}\) & \\ Computes & \\ \(Message=(MT_{i}+MP_{i})\) & \\ \(ID_{smd}\) & \\ \(t_{i}\) & \\ \(\xrightarrow{\{ID_{smd},ID_{rsmd},message,t_{i}\}}\) & \\  & \\  & \\  & \\  & \\ Acknowledgment of _message_ & \(\xleftarrow{\{ID_{smd},message,t_{i}\}}\) \\ Acknowledgment of _message_ & \\ \hline \hline \end{tabular}
\end{table} 
Table 8: V2V Communication phase. the cluster are inter-connected directly and can communicate with each other. Outside the cluster, communication vehicles can communicate using corresponding Cluster Heads. The cluster structure in our system primarily consists of a designated head, who assumes a leadership role, and the remaining vehicles within the cluster, which function as members. Figure 2 shows the lattice of our proposed VANET for V2V and V2I communications. The range of clusters in this scenario is 400 m. The central cluster is subdivided into a 100 m range for each. The CA performs the registration, authentication, monitoring, and allowing of vehicles' communications. The base station provides the network link to CH and CA. The CA server is responsible for issuing and managing digital certificates, ensuring the authenticity and integrity of communication in the system. Conversely, the base station provides Internet signals, enabling connectivity and network access for the devices within its coverage area. Due to the dynamic nature of moving vehicles in a vehicular ad hoc network (VANET), various sources of distortion can arise, potentially impacting communication effectiveness between vehicles. To mitigate these challenges, a specific VANET may employ the concept of a 400 m cluster. This cluster refers to a grouping of vehicles within a 400 m radius to enhance communication reliability and minimize distortion effects. By organizing vehicles into clusters, proximity-based communication is prioritized, allowing for more efficient transmission of messages and data. Within a cluster, vehicles are closer to each other, reducing the impact of signal attenuation, interference, and other distortions that can occur in VANET environments. The 400 m range is chosen based on the characteristics of the wireless communication technology, the expected vehicle density, and the desired trade-off between cluster size and communication performance. Setting a specific cluster size helps improve the quality and reliability of communication within the VANET. By limiting the cluster size to 400 m, vehicles in the same cluster are more likely to have stronger signal strengths, lower path loss, and reduced interference, thereby improving the overall communication performance and ensuring the timely and accurate exchange of information [65].