# An Improved Routing Approach for Enhancing QoS Performance for D2D Communication in B5G Networks
## 3 System Model
### Performance Evaluation Metrics  
The objective of the extensive simulation is to evaluate the performance of the MBLCR scheme by assessing the effects of well-known conventional routing schemes. The following parameter metrics are used to illustrate the performance of the routing approaches:  
1. [label=()]
2. Throughput: the ratio between the total number of data packets received at the destination device to the time spent during the data packet transmission. It can be calculated as follows (in Kbps): \[\text{Throughput}=\frac{(\sum N_{Rec}\times 8)}{\sum T_{simulation}}\times 1000\ \text{kbps}\] (12) where \(T_{simulation}\) is the time spent during the data packet transmission and \(N_{Rec}\) refers the total number of data packets received at the destination.
3. End-to-End Delay: the average time taken by the data packets to successfully transmit messages across the network between the source and the destination devices. The end-to-end delay includes route discovery latency, retransmission, buffering, and queuing delays. The end-to-end delay is calculated as follows:  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Simulation Parameters** & **Values** \\ \hline Routing approaches & MBLCR, MEQSA-OLSRv2, and MP-OLSRv2 \\ \hline Simulation time & 200 s with 200 iterations \\ \hline Application traffic & Constant Bit Rate \\ \hline Application packet size & 512 bytes \\ \hline Initial battery level & 3600 mAh \\ \hline Generic energy model & P\({}_{Transmission}=1300\) mW and \(P_{Rec}\)\(=900\) mW \\ \hline Battery model & Linear battery model \\ \hline Signal transmission power & P\({}_{t}=31.623\) mW \\ \hline Transmission range & 270 m \\ \hline Mobility & RWP model min speed 10m/s, max speed 60 m/s \\ \hline Simulation area & 500 m \(\times\) 500 m \\ \hline Application packet size & 512 bytes \\ \hline Data rate & 11 Mbps \\ \hline Wireless channel frequency & 2.4 GHz \\ \hline Path loss model & Two ray ground \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation parameter values.  
\[\text{EED}= \frac{1}{N_{Rec}}\sum_{c\in N}Delay(c)\] (13) where \(Delay(c)\) combines the entirely delay that occurs during the data packet transmission in the network.
3. Packet Delivery Ratio (PDR): the ratio between the total number of packets received at the destination and the total number of packets transmitted from the source to the destination devices in the network. The PDR is directly aligned to the efficacy of a multicast routing, i.e., the higher the PDR value, the more efficient the routing protocol. It can be computed as follows: \[\text{PDR}=\frac{N_{Rec}}{N_{Sent}}\times 100\] (14) where \(N_{Sent}\) defines as the total number of packets transmitted in the network from the source device.
4. Packet Drop: the total number of packets dropped before reaching the destination device. Packets drop is computed as the difference between the total number of packets transmitted and the total number of data packets received between the source and the destination device during data transmission in the network. \[\text{Packets Drop}=N_{Sent}-N_{Rec}\] (15)
5. Energy Consumption: the network devices' total energy consumption for significant data packet transfer throughout the network simulation time. Energy consumption is computed as follows: \[\text{Energy Consumption}=\frac{1}{N}\sum_{c\in N}E_{Total}(c)\] (16) where \(E_{Total}(c)\) refers to the total amount of energy consumption by the network devices and \(N\) refers to the total number of devices in the network.
6. Energy Cost: the ratio between the total energy consumption of the network devices for significant data packet transmission and the total number of packets successfully transmitted to the destination. It is computed as follows: \[\text{Energy Cost}=\frac{\text{Total energy consumption of the network devices}}{N_{Rec}}\] (17)