# Adaptive QoS-Aware Multi-Metrics Gateway Selection Scheme for Heterogenous Vehicular Network +
## 4 Simulation Experiment Settings  
The simulation findings of the proposed AQAGS scheme are presented in this section to verify its validity. We compare the proposed AQAGS with the CMGM scheme [22] and Adroit scheme [28]. The CMGM scheme is based on cluster formation and CH election before the gateway has been selected. Conversely, the Adroit scheme is a non-cluster-based scheme where the source vehicle communicates to and directs the surrounding vehicles to look for a vehicle that could serve as a gateway for accessing the infrastructure. The simulation was carried out using the SUMO mobility simulator [42] and NS2 [43] network simulator. The SUMO simulator was used to generate the vehicular mobility model, whereas the NS2 simulator was used to measure the network performance. The trace file generated by the SUMO analysis was used as an input file for the NS2 simulation to define the node's position and movement. In the evaluation phase, NSMIRICLE [44]was patched with NS2 to accommodate several interfaces in a wireless node. Moreover, the IEEE 802.11p package was implemented to enable V2V communication [45] while the LTE module [46] enabled LTE infrastructure communications. The simulation scenarios focused on the highway model, where two streams of vehicles move in opposite directions. For each direction, the road is divided into two lanes, and the vehicles are set to change the lane frequently to emulate the real mobility of vehicles on a highway road. We assume that each vehicle knows its position and velocity. Two types of applications are used, DT and NDT. For DT, an FTP application was used in which a packet of 1000 bytes was sent every 0.03s. The data rate for the FTP was assumed to be 0.3 Mbps. For NDT applications such as VoIP, 160 bytes packets were sent every 0.02s, and the data rate was set to 0.064 Mbps. We assumed 20% of the vehicles to act as IVs in each of the simulation settings. Of this 20%, 10% of the vehicles used VoIP applications and another 10% used FTP. On the other hand, the infrastructure comprised several LTE-eNBs located at the border of the highway. The vehicles directly connected to an LTE-eNB were expected to receive a higher \(RSS\). We also assumed that all vehicles are located inside the LTE-eNBs' coverage zone. Four scenarios were tested and for each scenario, the packet delivery ratio (_PDR_) (Equation (13)), throughput (Equation (14)), delay (Equation (15)), and control packet overhead (_CPO_) (Equation (16)) were measured and compared with the selected mechanisms. The reset of the important parameter settings for VANET and LTE modules are shown in Tables 4 and 5, respectively. \begin{table}
\begin{tabular}{l l} \hline \hline
**Parameter** & **Possible Values** \\ \hline Type of road & Highway \\ No. of lanes & 2 \\ Maximum speed & 20-160 km/h \\ No. of vehicles & 50-500 \\ Physical/MAC protocols & IEEE 802.11p \\ Transmission range \(TR_{max}\) & 300 m \\
802.11p data rate & 11 Mbps \\ Interface queue type & Drop Tail/PriQueue \\ Interface queue length & 50 Packets \\ Gateway broadcast timer & 1 s \\ Antenna type & Antenna/OmniAntenna \\ Application type & FTP, VoIP \\ FTP packet size & 1000 bytes \\ VoIP packet size & 160 bytes \\ The data rate of FTP & 0.3 Mbps \\ The data rate of VoIP & 0.064 Mbps \\ Residual load (\(RL_{eNSht}\)) & 80\% \\ TTL & 1 s \\ Simulation period & 500 s \\ Stop time & to 3 s \\ \hline \hline \end{tabular}
\end{table} 
Table 4: VANET Parameters.