## 3 Results and Discussion
### NS2 Simulation Results  
Network Simulator version 2 (NS2) is an event-driven tool deployed for the simulation of wired and wireless network operations and protocols (such as transport layer and routing protocols). Its flexibility, modularity, open-source availability, mechanism modifiability (based on users' preferences), stability, and extensibility have led to its popularity in the network research community. Community researchers and developers are continually working on the enhancement of NS2 [41; 42]. Consequently, NS2 is used to simulate the model proposed in this research work. In the proposed model, it is assumed that all vehicles are keeping a safe distance from each other. In most countries, to ensure road safety and reduce the possibility of collision, as a general guideline, a sufficient distance must be kept between each driver's vehicle and the one in front of him/her. The 2 s rule is often used as a rule of thumb and is being taught at driving schools as the minimum distance that should be maintained between two vehicles. According to [43], the safe distance between every two vehicles can vary between  
Figure 11: Vehicle transmission power (\(P_{V}\)) (dBm) versus overall achievable data rate (bit/s). Figure 10: Vehicle transmission power (\(P_{V}\)) (dBm) versus required interference power (\(P_{l}\)) (dBm). 1 and 2 s assuming ideal conditions, according to the rules of different countries. Regarding the standard lane width, [44] stated that lane width for any road ranges from 3.0 to 3.5 m.  
Therefore, in the proposed model, it is assumed that all vehicles are moving at varying speeds ranging from 30 km/h to 60 km/h, the road width is 3.5 m, and the distance between any two consecutive vehicles follows the 2 s rule. The network parameters used for simulation are listed in Table 3. Vehicles' mobility patterns were generated using NS2. Moreover, for system performance evaluation, AWK scripts were used to obtain packet delivery ratio (PDR) as shown in Figure 12, packet loss rate (PLR) as shown in Figure 13, and average end-to-end delay (E2E) as shown in Figure 14. In Figures 12-14, the simulation results were reported by assuming different counts of vehicles ranging from 100 to 250. In each figure, the results of two models were compared: a model without interference power control and a model with interface power control (proposed model). According to Figure 12, when the interference power control is not applied, it can be observed that the PDR has increased almost linearly as the number of vehicles increased. This can be justified by the following. As the number of vehicles increases, they tend to get out of the range of the interference sources, which allows more packets to successfully reach the destination, with minimal packet loss, thus increasing the PDR. However, when interference power control is imposed (proposed model), the PDR tends to remain almost constant with minimal changes. The vehicles experience minimum interference due to power control, thus allowing packets to successfully arrive at their destinations. As the number of vehicles increase, the PDR will not vary as all vehicles are experiencing minimum interference, which ensures the delivery of generated packets with minimal losses. Similarly, in Figure 13, when interference power control is not imposed, the PLR tends to decrease almost linearly as opposed to a nearly constant PLR with minimal variation when the proposed model is applied. In case of no interference control, the greater number of vehicles, the higher the number of vehicles outside the range of interference, thus fewer packets being lost due to interference and less PLR being recorded. In the proposed model, the reported PLR does not vary with the increase in the number of vehicles because the vehicles are already experiencing minimal interference. Therefore, the PLR will not vary as more vehicles are introduced.