# Intersection-Based Link-Adaptive Beaconless Forwarding in Urban Vehicular Ad-Hoc Networks
## 4 Performance Analysis
### Scenario Setup and Performance Metrics
Here, all the variables of Equations (22) and (23) are given in dB. The key simulation parameters used for evaluating the results are highlighted in \[L_{t}=20\times\log(4\times\pi\times\frac{d}{\lambda}\times|1+(\mathrm{Y}_{\perp }\times e^{j\times\varphi})|^{-1}), \tag{14}\]2 Although the duration of entire simulation is 300 s, there is no data packet exchange between the nodes for the first 200 s and the only event during this time is node movement, followed by 100 s of data packet exchange between the nodes. This is done to avoid cold start issues in the results. For evaluating the network performance, three performance metrics are considered. The PDR is the ratio between the number of packets received at the destination and the total number of packets sent by the source node. The average ETE delay refers to the average time taken for a data packet to be transmitted across a network from source node to destination. In addition to PDR and average ETE delay, the PRC is proposed to give a measure of unicast capability of a receiver-based routing \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Area & 1200 m \(\times\) 1200 m \\ Simulation time & 300 s \\ Number of simulation runs & 30 \\ Transmission range & 450 m \\ Transmission power & 29.3 dBm \\ Channel frequency & 5.9 GHz \\ MAC, PHY parameters & IEEE 802.11p \\ Data traffic & CBR \\ Data packet size & 512 B \\ Buffer size & 51.2 kB \\ Nominal bandwidth & 27 Mbps \\ Antenna type & Omnidirectional \\ Antenna height & 1.895 m \\ \(A_{eff}\) & 0.9691 dB \\ \(A_{mismatch}\) & 0.3 dB \\ \(A_{connection}\) & 0.2 dB \\ Pathloss model & Two ray interference \\ Shadowing effect, \(\sigma\) & 4 dB \\ Receiver sensitivity & \(-\)71.65 dBm \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Simulation parameters. scheme. Most of the receiver-based schemes try to minimize multiple relay nodes at single hop level by discarding duplicate packets, by using forwarding zone and assigning waiting time. However, in some situations such as when the waiting time of multiple nodes is similar, there are chances of having multiple relay nodes, thereby leading to multiple path formation in the network. By accounting for PRC, the ability of a routing protocol to suppress unnecessary multiple relay nodes at single hop level can be determined. PRC is calculated as follows:  
\[\text{PRC}=\frac{\sum_{i=1}^{n}N_{ifd}}{(H_{ave}-1)\times N_{rec}}-1, \tag{24}\]  
where \(N_{ifd}\) is the the total number of data packets forwarded by intermediate relay node \(i\), and \(\sum_{i=1}^{n}N_{ifd}\) refers to the summation of total number of data packets forwarded by all \(n\) intermediate relay nodes. \(H_{ave}\) is the average number of hops that a data packet traverses before reaching destination and \(N_{rec}\) is the total number of data packets received at destination. Here, single hop communication involving only source and destination is excluded while calculating \(H_{ave}\) and \(N_{rec}\). A PRC value of 0 implies a perfect unicast operation while any value greater than 0 represents the presence of multiple relay nodes at single hop level. Figure 4 illustrates two different scenarios of data packet transmission for a better understanding of the PRC metric. Figure 4a shows the perfect unicast transmission case. Here, each node is in the wireless range of two nodes at maximum (one node forward and one node backward). As depicted in the figure, the source node broadcasts 3 data packets which are then forwarded by the intermediate relay nodes (A and B), resulting in a total of 6 data packets being relayed by the intermediate nodes. These data packets are then received at the destination after traversing an average of 3 hops. Upon computing PRC for this scenario using Equation (24), a PRC value of 0 is obtained.