# Adaptive QoS-Aware Multi-Metrics Gateway Selection Scheme for Heterogenous Vehicular Network +
## 5 Results and Discussions
### Evaluation of Mixed Vehicle Applications versus Vehicle Speed  
In this section, we evaluate how the vehicle speed affected the effectiveness of the mechanisms in the proposed AQAGS scheme and the equivalent mechanisms. The speed of the vehicles was changed from 20 to 160 km/h with an increasing interval of 20 km/h, and the number of vehicles was kept at 100. Mixed traffic (MT) of VoIP and FTP applications were used. Figure 10a illustrates how the PDR value is generally impacted by changes in vehicle speed. The PDR tended to decrease as the vehicle speed rose. All three of the schemes follow the same pattern. The AQAGS scheme, however, performed 18.33% and 18.73% better than CMGM and Adroit, respectively. The AQAGS method reported a 98.9% PDR for a lower vehicle speed of 20 km/h, which was 18.36% and 23.57% higher than CMGM and Adroit, respectively. The PDR for the AQAGS scheme dropped to 85.58% when the speed of the vehicles increased to 160 km/h, but it was still 15.13% and 19.24% higher than that of the CMGM and Adroit methods, respectively. The LLT between the IV and MGW was predicted by AQAGS, which accounts for this performance. The relative velocities of the vehicles are taken into account by the LLT, which provides an estimate of how long the vehicles can remain connected. The IV keeps track of LLT parameters as the vehicle's speed rises and knows exactly where to start the search for a new MGW before  
Figure 9: Evaluation of mixed application types (FTP vs. VoIP) vs. the number of vehicles: (**a**) the number of vehicles vs. the average delay; (**b**) the number of vehicles vs. the CPO. the link breaks. In the cluster-based CMGM scheme, the speed of the cluster members affects how stable the clusters are. The clusters become unstable and require frequent re-formulation as the vehicle speeds rise, which can result in higher packet drops that have an impact on the PDR value. The PDR value reported by the CMGM scheme was still 5% higher than the Adroit scheme's value. At lower and higher vehicle speeds, the PDR reported by Adroit was 75.54% and 66.35%, respectively. In Adroit, the best MGW is determined without consideration of the LLT. In other words, the IV can select the MGW with the shortest connection time, which causes frequent link breaks that impact the PDR. Figure 10b displays how changes in vehicle speed affect the VANET network's overall throughput. For all three of the tested schemes, changing the vehicle speed had a serious effect on throughput. The throughput decreased with increasing vehicle speeds. However, for both low-speed and high-speed vehicles, the proposed AQAGS scheme outperformed CMGM and Adroit in terms of throughput. When compared with the CMGM and Adroit schemes, the throughput revealed by AQAGS was 7.52% and 6.83% higher, respectively. This is so that the best MGW can be chosen, which is influenced by the vehicle speed in AQAGS. This aids the IV in deciding which MGW it can trust to maintain a stable connection with for a while. Additionally, depending on the application, some IVs never require an MGW connection to connect to the LTE network; instead, they can directly send packets to the infrastructure. However, when the vehicle's speed increased from 20 km/h to 160 km/h, the throughput of the proposed AQAGS scheme decreased by 1.46%. This decline was marginally greater than the throughput declines demonstrated by CMGM and Adroit, which were 0.83% and 1.36%, respectively. When examined further, we noticed that the CMGM scheme reported a lower throughput than the AQAGS scheme. The reason the CMGM method was able to maintain the throughput drop was that they arranged the vehicles in clusters, which improved the management of the links and helped ensure that the data packets arrived at their destination safely. Furthermore, Adroit performed worse than the competition in terms of throughput, which can be explained by the fact that Adroit never considers the connection time, which typically influences vehicle speed when selecting the best MGW.