# Security Performance Analysis of Full-Duplex UAV Assisted Relay System Based on SWIPT Technology
## 4 Experimentation and Simulation
When \(H_{1}\) increasing from 0.75 to 0.9, the line-of-sight channel link for effective information transmission is enhanced and the probability of transmission of LOS increases, and therefore, the probability of connectivity CP increases. \begin{table}
\begin{tabular}{c c} \hline
**Parametric** & **Simulation Value** \\ \hline \(W_{A}\) & \((0,0,0)\) \\ \hline \(W_{B}\) & \((D_{x},0,0)\) \\ \hline \(H_{1}\) & 1 \\ \hline \(H_{2}\) & 1.4 \\ \hline \(W_{U}\) & \((0.3D_{x},0,H_{1})\) (CP*) \\  & \((0.8D_{x},0.8,H_{1})\) (SOP*) \\ \hline \(W_{E}\) & \((0.4D_{x},0,H_{2})\)(CP*) \\  & \((0.4D_{x},0.4,H_{2})\) (SOP*) \\ \hline Environmental parameters: \(\omega_{1}\) & 4.88 (CP*) \\  & 27.27 (SOP*) \\ \hline Environmental parameters: \(\omega_{2}\) & 0.48 (CP*) \\  & 0.08 (SOP*) \\ \hline Self-interference channel power gain at destination node B: \(S_{B}\) & 0.1 (CP*) \\  & 0.2 (SOP*) \\ \hline Self-interference channel power gain for UAV U: \(S_{u}\) & 0.5 \\ \hline Path loss index: \(\alpha_{L}\) & 2 \\ \hline Path loss index:\(\alpha_{N}\) & 3.5 \\ \hline network transmission rate: \(R_{t}\) (\(\text{bps}/\text{Hz}\)) & 0.5 \\ \hline eavesdrop transmission rate: \(R_{E}\) (\(\text{bps}/\text{Hz}\)) & 0.2 \\ \hline noise power: \(N_{0}\) (dBm) & 10 \\ \hline \(k_{m}\) & 1 \\ \hline \(k_{M}\) & 10 \\ \hline powerdistributionfactor : \(\lambda\) & 0.7 \\ \hline power split ratio: \(\beta\) & 0.4 \\ \hline Power conversion efficiency factor: \(\eta\) & 0.9 \\ \hline noise-to-power ratio: \(\xi\) & 5 \\ \hline Total Transmit Power: \(P\) (W) & 150 \\ \hline Noise transmission power at destination node B: \(P_{B}\) (W) & 100 \\ \hline \end{tabular}
\end{table} 
Table 2: Simulation parameters. Figure 4: Relationship between CP and UAV self-interference gain \(S_{u}\) under different flight altitude conditions at UAV relay node U.  
Figure 3: CP vs. power allocation factor \(\lambda\) for different power splitting ratio \(\beta\) conditions. Figure 2: CP vs. total transmit power \(P\) for different UAV node U self-interference channel gain conditions. Figure 5 reveals the relationship between SOP and power allocation factor \(\lambda\) under different eavesdropping rate thresholds \(R_{E}\). As can be seen from the figure, when the total transmit power \(P\) is certain, the SOP increases with the increase of \(\lambda\). This is because an increase in \(\lambda\) for a certain \(P\) leads to an increase in \(P_{A}\) and a decrease in the power \(P_{U}\) used to send the jamming signal to the UAV eavesdropping node E. This causes the channel capacity of the eavesdropping link to become larger, at which point the information is more likely to be eavesdropped and the secrecy outage probability SOP increases. The smaller the power allocation factor \(\lambda\) is, the better the secure transmission of the system is, but the security of the system is limited by the system connectivity. From the conclusion of Figure 1, it can be seen that the system can only be connected when \(\lambda\geq\lambda^{*}\), and the larger the \(\lambda\) is, the better the connectivity is, so there is a trade-off between the system's connectivity and security. In addition, when \(\lambda\) is certain, the SOP decreases as the eavesdropping rate threshold \(R_{E}\) increases, and the smaller the threshold \(R_{E}\) the greater the change in the value of the power allocation factor \(\lambda\) is required when raising the same value of the security interruption probability. This suggests that when security needs are high, increasing security by an equal margin comes at a greater cost in terms of eavesdropping interference. Plot (a) in Figure 6 compares the effect of different environmental parameters on the secrecy outage probability SOP. The (b) plot in Figure 6 is a localized enlargement of the (a) plot, where A takes values from 0.58 to 0.62.