## 2 Method
By iterating through different configurations and testing the impact of small adjustments, the fine-tuning process sought to balance the trade-offs between competing performance metrics, such as minimizing routing overhead while maximizing throughput, as shown in Figure 1. The outcome of this stage was a set of optimized parameter values that enhanced the adaptability, efficiency, and robustness of the AODV and GPSR protocols, ensuring they performed at their best in dynamic, real-world wireless networks. The study used the INET3.5 simulation framework and OMNET++ simulator. The network protocol stack in INET3.5 provides a reach library of network protocol implementation and architecture. The implementation of a specific set of protocols can be combined in a compound module. The combined module is used in this work to implement a VANET node based on a wireless node module (WN) in INET3.5, which shows a snapshot of the internal structure of a WN for CM-AODV protocol implementation. WN is the basic building structure of the protocol stack. It comprises wireless, mobility, network, routing, transport, and application sub-modules. Each sub-module implements a functionality of a specific layer in the network protocol stack. The design of the wireless communication link used in this research work is detailed in the Supplementary Materials. Three VANET scenarios (highway, city, and hybrid) are used for evaluation purposes throughout this chapter. VANET scenarios are realizations of the Changlun City Map, as shown in Figure 2. The highway scenario is based on the extraction of the highway across Changlun (green line). The city scenario represents the internal roads of Changlun (red  
Figure 1: Protocols measurement process flow. and blue lines), and the hybrid scenario is a combination of city and highway scenarios. Table 1 shows the simulation parameters for these scenarios. In this simulation setup, the MAC layer used is the IEEE 802.11 protocol, which is widely employed in wireless communication simulations, including Vehicular Ad Hoc Networks (VANETs) and Mobile Ad Hoc Networks (MANETs). Specifically, for vehicular communication, we utilize the 802.11p extension, which is designed for Vehicle-to-Everything (V2X) communication, including Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **City** & **Highway** & **Hybrid** \\ \hline Dimension & 1000 m \(\times\) 800 m & 2000 m \(\times\) 20 m & 2000 m \(\times\) 800 m \\ \hline Vehicles speed & 30–70 km/h & 80–110 Km/h & 30–110 Km/h \\ \hline Number of Vehicles & 30–60 & 20–40 & 60–100 \\ \hline Number of RSU & 7 & 8 & 15 \\ \hline Communication range & 300 m & 300 m & 300 m \\ \hline MAC protocol & IEEE 802.11p & IEEE 802.11p & IEEE 802.11p \\ \hline Data rate & 18 Mbps & 18 Mbps & 18 Mbps \\ \hline Traffic generation model & Burst application & Burst application & Burst application \\ \hline Packet size & 1024 byte & 1024 byte & 1024 byte \\ \hline Mobility model & Linear, rectangular, trace & Linear & Linear, rectangular, trace \\ \hline \hline \end{tabular}
\end{table} 
Table 1: VANET simulation scenarios. Figure 2: Changlun City map extraction: blue lines and red lines represent internal city roads, and the green line represents the highway road. (V2I) interactions. The 802.11p MAC layer is ideal for dynamic, high-speed environments like vehicular networks, providing efficient communication in such challenging scenarios. This setup allows us to accurately simulate the communication dynamics necessary for the VANET application, as shown in Table 1.  
This study considered five routing protocols, including CM-AODV, CM-GPSR, AODV, GPSR, and IOLSR; each routing protocol configuration (referred to as routing profile) defines the value of these parameters in a specific experiment. Table 2 presents these parameters for the five routing protocols and their ranges.