# A Robust Routing Protocol in Cognitive Unmanned Aerial Vehicular Networks
## 6 Simulation Results
### Performance Evaluation  
The graph in Figure 5 illustrates the relationship between the number of nodes in the network and the time it takes for data to be transmitted, known as end-to-end delay. The analysis considers two different packet sizes: 512 bytes and 1024 bytes, conducted within a simulated environment using UAVs with a transmission range of 550 m.  
When utilizing 512-byte packets, the end-to-end delay ranges from 0.23 to 0.318 s, while for 1024-byte packets, it ranges from 0.116 to 0.894 s.  
The findings indicate that as the number of nodes increases, the end-to-end delay generally decreases. This phenomenon is attributed to the availability of more pathways for data transmission, resulting in improved efficiency. Interestingly, the use of larger packet sizes, such as 1024 bytes, results in slightly higher end-to-end delays compared to smaller packet sizes. This is due to the increased processing and transmission time required for larger packets. The graph in Figure 6 depicts the relationship between the number of trials and throughput, representing the quantity of data successfully delivered to the target node per unit time. The analysis examines two different packet sizes: 512 bytes and 1024 bytes, conducted within a simulation environment utilizing UAVs equipped with a transmission range of 550 m.  
For packet sizes of 512 bytes, the throughput values range from 21.1858 to 27.883 units (e.g., Mbps or packets per second). This variation in throughput reflects the effectiveness of the TDMA method in allocating time slots for data transmission among multiple UAVs. Similarly, for packet sizes of 1024 bytes, the throughput values range from 42.4218 to 54.9416 units. The higher throughput values for larger packet sizes indicate the efficient utilization of allocated time slots, allowing for increased data delivery rates per unit time. The TDMA method plays a crucial role in managing these throughput values by efficiently dividing the transmission time among UAVs, thereby optimizing data transfer rates within the specified transmission range of 550 m. This approach ensures reliable and efficient communication among UAVs in dynamic environments. The findings suggest that as the number of trials increases, the throughput tends to fluctuate. This fluctuation may be attributed to various factors such as network congestion, packet loss, or environmental interference. Additionally, it is observed that for both packet sizes, the throughput tends to be higher when using larger packets (1024 bytes) compared to smaller packets (512 bytes). This can be attributed to the larger amount of data being transmitted in each packet, leading to higher throughput. Figure 5: Comparison of End to End Delay for packet sizes of 512 and 1024. The graph in Figure 7 illustrates the relationship between trials and the packet delivery ratio, representing the percentage of successfully delivered packets out of the total packets sent. The analysis evaluates two different packet sizes: 512 bytes and 1024 bytes, within a simulation environment utilizing UAVs with a transmission range of 550 m.  
For packet sizes of 512 bytes, the packet delivery ratio ranges from 75.454% to 98.456%, while for packet sizes of 1024 bytes, it varies from 72.12% to 97.818%. The findings indicate that as the number of trials increases, the packet delivery ratio tends to fluctuate. This fluctuation may be attributed to various factors such as network congestion, packet loss, or environmental interference. Additionally, it is observed that the packet delivery ratio remains relatively consistent across different packet sizes, with slight variations within the range of results. This suggests that the proposed protocol effectively maintains packet delivery performance regardless of the packet size being transmitted. The graph in Figure 8 portrays the relationship between trials and the normalized routing load, which represents the average amount of routing overhead incurred per node  
Figure 6: Comparison of throughput for packet sizes of 512 and 1024.