## 4 Simulation Results
Figure 4: Outage probability for DH with SLIPT-based EH FSO link with different weather conditions and varying pointing error levels. \(\alpha_{R}=\alpha_{D}=4.2\), \(\beta_{R}=\beta_{D}=3\), \(\gamma_{th}=1\), and \(\tau=0.5\). Figure 6 shows the ergodic capacity performance of a SLIPT-based EH DH FSO link with different atmospheric turbulence regimes and varying pointing error levels. As expected, the erdogic capacity performance is at its best when both the atmospheric turbulence and the pointing error levels are weak. Figure 6: Ergodic capacity for DH with SLIPT-based EH FSO link with varying atmospheric turbulence and pointing error conditions. \(\omega=0.10168\), and \(\tau=0.5\). Figure 7 illustrates the average BER of SLIPT-based DH FSO links with different weather conditions and varying pointing error levels. It can be observed from this figure that the average BER performance is degraded by both foggy weather conditions and high pointing error levels, as expected. For instance, at \(\rho=28\) dB, a link over a clear air and with a low level of pointing errors gives a BER value of \(2.15\times 10^{-3}\), whereas the link over a foggy weather condition and with a high level of pointing errors gives a BER value of \(4.51\times 10^{-2}\). Figure 8 illustrates the throughput of the proposed SLIPT-based DH FSO link versus \(\tau\), the amount of time that is dedicated for energy harvesting. This figure shows the trade-off between the amount of time for energy harvesting and the achievable throughput of the communication system. It can be observed that the throughput decreases with the increase in the amount of time for energy harvesting. Specifically, the throughput rapidly falls as \(\tau\) approaches unity. For instance, a SLIPT-based DH FSO link with \(\rho=40\) dB and \(\xi=6.7\) experiences a 38.69% decline in throughput when \(\tau=0.4\). Figure 9 presents a comparison of an SH FSO link, a non-EH DH FSO link, and the proposed SLIPT-based EH DH FSO link in terms of their SOP performance metric. It can be observed from the figure that the proposed SLIPT-based FSO link outperforms the other two communication links. For instance, at \(\rho=28\) dB, the SLIPT-based EH DH FSO link yields an SOP value of \(7.8\times 10^{-3}\). However, to reach the same SOP value, the non-EH DH FSO link needs an extra 8 dB, and the SH FSO link requires approximately an extra 10 dB of \(\rho\). Figure 10 illustrates the SOP performance of SLIPT-based EH DH FSO links with varying average SNR of the eavesdropper and with different weather conditions. This figure demonstrates that an increase in the average SNR of the eavesdropper degrades the SOP performance. Additionally, foggy weather conditions worsen the SOP, as expected. For example, when \(\mu_{E}=8\) dB and with clear air, the SOP value is \(1.5\times 10^{-2}\) at \(\rho=12\) dB. Figure 7: Average bit error rate for DH with SLIPT-based EH FSO link with different weather conditions and varying pointing error levels. \(\alpha_{R}=\alpha_{D}=4.2\), \(\beta_{R}=\beta_{D}=3\), and \(\tau=0.5\). But when \(\mu_{E}=20\) dB with clear air, the SOP gives a value of \(1.1\times 10^{-1}\) at the same average SNR. Figure 8: Throughput for DH with SLIPT-based EH FSO link versus \(\tau\) with different levels of pointing errors and varying values of average SNR. \(\alpha_{R}=\alpha_{D}=4.2\), \(\beta_{R}=\beta_{D}=3\), and \(\omega=0.9065\). Figure 11 shows the SPSC of SLIPT-based EH DH FSO links with varying atmospheric turbulence and pointing error levels. It can be observed from the figure that the SPSC approaches unity as the value of \(\rho\) increases. It can also be seen from the figure that the SPSC has its highest value when both the atmospheric turbulence and the pointing error levels are weak. For instance, with weak atmospheric turbulence and \(\xi=6.7\), the SPSC yields a value of \(8.7\times 10^{-1}\) at \(\rho=11\) dB. However, with strong turbulence and with \(\xi=1.1\), the SPSC has a value of \(6.2\times 10^{-1}\) at the same average SNR.