# A Semi-Random Elliptical Movement Model for Relay Nodes in Flying Ad Hoc Networks
## 5 Performance Evaluation
### Simulation Results  
To clearly present the simulation results, this section provides a quantitative comparison of the relative performance of the three mobility models--SREM, SRCM, and RWP--based on key performance metrics. All simulations were conducted under identical environmental settings and repeated ten times to ensure statistical reliability. The analysis focused on core communication indicators, including PDR, throughput, EED, connection time, and average hop count. A summary of the overall results is presented in Table 4.  
Figure 7 illustrates the PDR results measured over ten simulation runs for the three mobility models: SREM, SRCM, and RWP. The SREM model consistently maintained a PDR above 90% across all trials, exhibiting both the highest delivery rate and the lowest variability. This performance is attributed to its path-aligned design, which concentrates node movement along the communication axis, thereby minimizing link breakages and sustaining stable relay connections. The SRCM model demonstrated generally good performance, with PDR values ranging between approximately 75% and 85%, though some variability was observed across runs. While its circular trajectory provides uniform coverage, the lack of alignment with the communication axis likely caused occasional instability in relay paths. The RWP model showed the lowest and most unstable performance among the three, with PDR fluctuating widely between below 30% and up to 70% depending on the trial. This outcome is primarily due to RWP's fully random, memoryless mobility pattern, which \begin{table}
\begin{tabular}{l c c c c c} \hline \hline
**Mobility Model** & **PDR [\%]** & **EED [s]** & **Throughput [KB/s]** & **CT [s]** & **Hop Count** \\ \hline SREM & 91.3 & 0.061 & 110.3 & 23.8 & 11.2 \\ SRCM & 81.4 & 0.089 & 98.1 & 18.1 & 14.5 \\ RWP & 51.7 & 0.175 & 61.0 & 10.4 & 21.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Simulation performance of mobility models. results in frequent route changes, increased hop counts, link disconnections, and higher packet loss. The differences in PDR performance are directly reflected in the observed throughput results. The SREM model achieved an average throughput of approximately 110 KB/s, significantly outperforming the other two models under identical simulation conditions. In contrast, the SRCM model recorded about 98 KB/s, while the RWP model demonstrated a considerably lower throughput of around 61 KB/s. This indicates that RWP not only suffers from reduced packet delivery but also exhibits a substantial degradation in overall network data-handling capacity. Despite all three models operating with the same number of UAVs, within the same simulation area, and under identical speed and communication parameters, SREM consistently achieved the highest throughput. This outcome suggests that the performance gains are not due to differences in network capacity but rather stem from SREM's path-aligned mobility structure, which enables more stable and efficient relay link formation. In essence, these results demonstrate that even when using the same network resources, structural differences in mobility design can lead to significant variations in performance--highlighting the practical advantages of path-centric relay mobility models in FANET environments. Figure 8 compares the average EED among the three mobility models: SREM, SRCM, and RWP. The SREM model consistently maintained a very low EED, averaging approximately 0.06 s, with minimal variance across trials, indicating strong temporal consistency. This performance is attributed to the model's elliptical mobility structure, which aligns node movement along the communication axis and enables more efficient path formation. Consequently, SREM achieved an average hop count of 11.2, contributing to its reduced delay. Figure 8: Comparison of EED for different mobility models: SREM, SRCM, and RWP. Figure 7: Comparison of PDR for different mobility models: SREM, SRCM, and RWP.