## 4 Results and Discussion  
The presented FSO and optical network integrated model is an investigation using optisystem and MATLAB simulation software. The performance is evaluated based on various parameters, such as input power, output power, different wavelengths, FSO transmission range, and divergence losses. The values of the used parameters are listed in Table 1, which are as per practical used models. Figure 3 shows the simulation analysis for different time diversity order (M = 1, 2, 3) using input power and BER. The plotted analysis explains that the BER improves at third order time diversity. The power level from negative to positive decreases the BER value for all the time diversity orders. The diversity with M = 3 gives BER = \(10^{-11}\) at a 3 dBm power level, which is considered acceptable efficiency against nonlinearities, FSO pointing errors, and co-channel interference. Thus, the results noted in Figure 3 encourage the system outcomes at diversity order 3. The presented FSO system is tested using different laser wavelengths (1535.1, 1540.1, 1545.1, and 1550.1 nm) based on output power versus BER. The laser signals with 1550.1 nm cross the FEC limit sooner than other transmissions. Maximum BER gap can be noted among 1535.1, 1540.1, 1545.1, and 1550.1 nm signal transmissions. For example, at \(-18\) dBm received power, the BER attained by 1550.1 nm signal is about 1.3 \(\times 10^{-13}\); on the other side at 1535.1 nm signal transmission, the BER is recorded above \(10^{-9}\). Figure 4 also includes the eye diagram investigation for the tested wavelengths. Figure 5 notes the analysis of the results for FSO transmission range (m) and divergence losses (dB). The estimations compare the conventional FSO system, the proposed FSO system without managed pointing and co-channel interference issues, and with managed pointing and co-channel interference issues. In addition, Figure 5 explains two scenarios: (1) the divergence losses increase with increasing the transmission range; (2) the divergence losses are set higher in the case of the conventional system and presented in the FSO and optical network hybrid system. It can be seen that the presented model fruitfully addresses the FSO pointing and co-channel interference errors. Figure 6 describes the correlation between back-to-back (B2B), 5 km path cover, and 10 km path cover FSO system, applying output power as a function of BER. The performance of B2B is ideal; however, the BER degrades with an increase in length. The outcomes of the FSO system are evaluated using EVM measuring element. This analysis is shown in Figure 7, which clarifies that the presented FSO and optical network mixed model has significant outcomes compared to the conventional FSO system. Figure 8 provides the correlation between the presented F-OFDM 5G transceiver and OFDM and UFMC in terms of PAPR and CDF. The fruitful PAPR is achieved by F-OFDM based signal transmission. The efficiency of the presented model is estimated for various optical beams, as shown in Figure 9. Figure 9 explains the outcomes for single optical beam transmission, Figure 9b shows two beam transmission, and Figure 9c presents the transmission for three optical beams. Figure 9d shows four optical beam transmission outcomes. The comparison of eye diagram estimation in Figure 9 defines that the presented system gives accurate results with multi beam transmissions. Figure 2: The 5G proposed transceiver for smooth transmission against nonlinear impairments. Figure 4: Comparison of different wavelengths using received power and BER. Figure 3: Time diversity analysis in terms of transmitted power and BER. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Transmitted power & \(-20\) to \(2\) dBm \\ Output power & \(-40\) to \(-14\) dBm \\ Downstream wavelengths & \(1535.1\) to \(1550.1\) nm \\ FSO length & \(1000\) m \\ Insertion loss & \(3\) dB \\ F-OFDM signal & \(790\) MHz \\ EA gain & \(20\) dB \\ \hline \hline \end{tabular}
\end{table}