## 5 Results and Discussion  
Table 1 shows the proposed parameters for the system model [proposed values] and values in Refs. [2; 17; 42] used in the system architecture. The proposed design parameters are specified in Table 1 [proposed] and [2; 17; 42]. We investigate the impact of the turbulence effect on the proposed system performance based on the OOK-M any-DPPM modulation as a function of M-ary DPPM-PAPM and other atmospheric parameters. Figure 2 shows the high gain (G = 30 dB) of the AT impact in the case of BER. MCB and CB are about the same, through AT strength rises [9; 10; 43; 44; 45; 46]. The curves of CB and MCB vary from GA. The high (a) (G) = 27 dB [42] and G = 30 dB [current work] with the ICC is shown in Figure 3. For M = 2 and (b) G = 8 dB, the present work shows the MCB, CB, and GA output. The MCB synchronizes with the GA on low G in Figure 3a but at high G is near the CB with as the ASEN decreases the TNV results. The GA at high G with no ICC and in the existence of ICC exceeds the CB and MCB. The CB extends the CL and bandwidth of the DPPM-PAPM receiver for noise equivalent B\({}_{\text{e}}\). The margin of the GA is greater than the MCB of the PAPM-M-DPPM. The MCB, CB, and GA output of a G = 8 dB with an ICC  
and M = 2 is shown in Figure 3b. The results are enhanced and validated with Ref. [42]. The MCB synchronizes with the GA at low G but gains considerably near the CB as the ASEN reduces the TNV impacts [43; 44; 45; 46]. In the case of BER targets of \(10^{-12}\), ST and WT using MCB, CB, and GA, the receiver sensitivity (RS) is applied for G =30.6 dB and \(I_{fso}=1500\) m [2; 9; 40] as shown in Figure 4a,b. Numerical results demonstrated that RSs are \(-51.49\) dBm (CB), \(-51.59\) dBm (MCB), and -50.53 dBm (GA), resulting in improvement and optimization as achieved in [2; 9; 40]. The RS of \(-51.49\) dBm (CB), \(-51.56\) dB (MCB), and \(-50.25\) dBm (GA) is presented for G = 30 dB, \(I_{fso}=2500\) m, at target BER of \(10^{-12}\) [Proposed work]. Figure 5 shows the BER against the optical SNR (OSNR) (dB) for the WDM-PON/HFFSO link with hybrid OOK/M-ary DPPM- and M-PPM using the CL M = 5, \(I_{fso}=4000\) m, and \(\text{D}_{\text{RX}}=25\) mm for ST. The hybrid OOK/M-ary DPPM-PAPM offers about 4 dB, 6 dB, and 8 dB OSNR improvements over 3-DPPM, 4-DPPM, and 5-DPPM of the ST for the WDM. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameters** & **Description** & **Refs. [2; 17]** & **Ref. [42]** & **[Proposed Work]** \\ \hline \(R_{b}\) & Data rate & 2.5 Gbps & 2.5 Gbps & 2.5 Gbps \\ \(R_{o}\) & Demux OBPF & 80 GHz & 76 GHz & 80 GHz \\ bandwidth & & & & \\ \(\lambda_{agg}\) & Wavelength & 1550 nm & 1550 nm & 1550 nm \\ \(\eta\) & Quantum & 0.75 & 0.9 & 1 \\ \(G\) & OA gain & 30.6 dB or 8.8 dB & 27 dB or 8 dB & 30 dB or 8 dB \\ NF & OA noise figure & 4.77 dB [2] & 4.77 dB [2] & 4.77 dB [2] \\ \(I_{fso}\) & FSO link length & 1000 m and 1500 m & 1000 m and 1500 m & 1500 m and 4000 m \\ \multicolumn{4}{c}{ASE noise} \\ \(m_{t}\) & polarization & 2 & 2 & 2 \\ \multicolumn{4}{c}{states} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: System parameters used for calculations in [2; 17; 42] and [Proposed work]. Figure 2: The bit error rate (BER) against an average irradiance [dB] for no turbulence (NT), and WT using Gamma-Gamma (GG) model and log-normal distribution. Figure 3: BER against average optical power (AOP) (dBm) using for (**a**) G = 27 dB [42] at 1500 m, and G = 30 dB [present work] at 4000 m and (**b**) G = 8 dB ST is demonstrated in [42] at 1500 m and [present work] at 4000 m.  
HFFSO optical fiber network, respectively at a target BER of \(10^{-12}\). The ST without the hybrid OOK/M-ary modulation format required greater power under the AT effects, ICC, and ASE noise, to achieve the same BER performance than ST with the hybrid OOK/M-ary DPPM scheme as shown in Figure 5. This suggests that the hybrid modulation scheme OOK/M-ary DPPM-PAPM based on WDM-HFSO communication is favored to ensure greater efficiency and greater performance in our design.