# Junction Selection Based on Optimal-Weighted Multiple Attributes for VANETs
## 3 Simulation Results  
The proposed protocol is simulated in NS-2 simulation software. The detail of simulation parameters is summarized in Table 1.  
In our city-simulation scenario, vehicles are distributed randomly on the two directions road segment. The vehicle mobility pattern is generated by using VanetMobiSim, and the map size is 2500 \(\times\) 2000 m\({}^{2}\). The simulation scenario is shown in Figure 4. There are also different numbers of junctions that have been considered. We have compared MADMJSR simulated results with previously proposed junction selection schemes GSR, E-GyTAR, and DMJSR. We compared the simulation result in terms of packet delivery ratio, end-to-end delay, and routing overhead. Packet delivery rate is defined as the percentage of packets that are successfully delivered to their destination vehicles. End-to-end delay is defined as the average delay incurred by the packet from its source to its destination. Routing overhead is the ratio of total control packets produced to the total data packets received at the destinations during the complete simulation.  
Figure 5 shows that the proposed protocol packet delivery ratio increases with an increasing number of vehicles compared to other schemes as MADMJSR utilizes optimal weight values for junction selection rather than static values. Moreover, it selects the road segment with the shortest distance and highest traffic density for packet forwarding. Consequently, a packet will be transmitted in the high-traffic density city area on the street to ensure high network connectivity. Many vehicles on the road segment can increment a high packet delivery ratio.  
Figure 6 illustrates that MADMJSR outperforms E-GyTAR, GSR, and DMJSR in terms of end-to-end delay as well. In MADMJSR, the highest traffic density, the shortest distance, and the mini-angle for junction selection are used. The existing protocols only consider traffic density or distance but do not consider the direction of the vehicle mobility, which  
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Parameters** & **Values** & **Parameters** & **Values** \\ \hline Simulation time & 200 s & MAC protocol & IEEE802.11 \\ \hline Map size & 2500 \(\times\) 2000 m\({}^{2}\) & Channel capacity & 2 Mbps \\ \hline Mobility Model & VanetMobiSim & Transmission range & 266 m \\ \hline Number junctions & 16 & Traffic model & 15 CBR connection \\ \hline Number roads & 24 & Packet sending rate & 0.1–1 s \\ \hline Number vehicles & 175 & size & 128 Bytes \\ \hline Vehicle speed & 60 km/h & Weight value & Distance: 0.2, Traffic density: 0.7, Angle: 0.1 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation parameters.  
can lead the packet away from the destination. This increases the end-to-end delay in packet sharing.  
Figure 7 shows the routing overhead of all three protocols with respect to the number of nodes. With an increase in the number of nodes, there is an increase in the routing  
Figure 4: City simulation area.  
Figure 5: Packet delivery ratio on an increasing number of vehicles.  
Figure 6: End-to-end delay on an increasing number of vehicles.  
overhead for all of the protocols. The proposed scheme has a higher routing overhead when compared with existing protocols. This is because, in the proposed scheme, three parameters are considered. Obtaining this information uses more network overhead than others. In addition, the proposed scheme has to rank the calculation result; it also takes some network overhead. However, other protocols do not undertake this process.