## 5 Results and Discussion
The target BER of \(10^{-10}\) is achieved for values of m \(\geq\) 100, while the BER becomes worse specifically at higher ICC and lower CL for value m \(\leq\) 100, as shown in Figure 6. For target BER of \(10^{-9}\), the resulting DPPM PP analysis for ICC M = 2 is compared to the OOK as shown in Figure 7. The M-DPPM-M-PAPM combination produces less PP than the OOK. The M-DPPM-M-PAPM improvement in the PP is improved as the CL number increases from M = 1 to 2 and the ICC sources [5; 8; 9; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56]. The proposed M-ary DPPM-M-PAPM approach increases receiver  
Figure 4: Receiver sensitivity (RS) (dBm) versus M-ary DPPM coding level is presented for the NT with (**a**) WT condition and **(b)** ST is demonstrated in [2], [present]. sensitivity in the WDM-M-HFFSO systems compared with OOK-NRZ and improves reliability and produces a lower PP of 0.2-3.0 dB PP for WT. Without adaptation to reach a BER of \(10^{-12}\), the modulation techniques decreased OSNR by 4 dB as shown in Figure 8.  
Figure 5: BER vs. OSNR (dB) for the WDM-PON/HFFSO link with hybrid OOK/M-ary DPPM and M-DPPM using \(\mathrm{D_{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{ \mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{\mathrm{ \mathrm{ \mathrm{  }}}}}}}}}}}}}} =25\) mm, M = 5, \(l_{g\circ}\) = 4000 m for ST.  
Figure 6: BER vs. the slot numbers (\(n\)) for the hybrid M-DPPM-M-PAPM using MCB, G = 30 dB. Compared to the hybrid OOK/M-ary DPPM, the M-n-PAPM requires 0.3 dB more power. The results demonstrate that the proposed hybrid OOK/M-DPPM and M-n-PAPM models for the WDM-FSO systems can be improved [54; 55; 56; 57; 58; 59; 60]. Table 2 summarizes the proposed modulation schemes of MPPM, M-ary-PAPM, and hybrid M-ary PAPM-MPPM with hybrid \(k\)-level \(n\)-pulse where \(k^{n}\) (with \(k\in\{1,\,2,\,\dots\}\)) [2; 8; 9; 17; 42; 50]. Figure 9 shows BER vs. the average RCL power input (dBm), \(\rm D_{RX}=25\) mm for M-ary DPPM and OOK for NT and (a) WT (b) MT and (c) ST for M-ary DPPM and G = 30 dB, M = 5. At the BER target of \(10^{-12}\), DPPM provides around 10-11 dB increases in sensitivity compared with the WDM-FSO OOK-NRZ as shown in Figure 9a [2; 9; 10; 17; 42; 56; 57; 58; 59; 60]. With a disability in the AT, DPPM's overall sensitivity is reduced to approximately 10 dB (WT), 8 dB (MT), and 8 dB, respectively (ST). The OOK-NRZ based FSO system offers about 7-9 dB for the  
Figure 2:0 Optical signal-to-noise ratio (OSNR) to BER performance for the hybrid OOK/M-ary DPPM and M-n-PAPM modulation scheme. Figure 2:1 PP vs. \(\rm C_{XT}\) for OOK comparison with DPPM-M-PAPM at M = 2 and OOK/M-DPPM-M-PAPM at \(\rm RFR=10^{-9}\) for NT (_crosstalk_ signals 35 and 50. DPPM scheme as shown in Figure 9b [2; 9]. With AT deficiency, DPPM is reduced to around 7 dB (WT), 8 dB (MT) and 8 dB (ST) [2; 9; 10; 17; 42; 43; 44; 45; 46; 47], respectively as shown in Figure 9c. M-ary PAPM-DPPM modulation provides about 10-11 dB increases in OOK-NRZ sensitivity for the WDM-FSO optical fiber network system in the absence of turbulence on the target BER with all AA as seen in Figure 10 [48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58]. When the turbulence and ASE noise is present, the OS is reduced to 10 dB (WT), 8 dB (MT), and 8 dB (ST) [present] in the sensitivity increase of PAPM DPPM over OOK NRZ [56; 57; 58; 59; 60; 61; 62]. It is necessary to ensure and continuously maintain the consistency and accuracy of the simulation models and algorithms with reality. This is accomplished mainly by comparing the simulation behavior to the simulation and experimental results achieved in [2; 5; 50; 9; 15; 42; 5]. Also, in our research several (successful) comparisons were done, sets of the previous research and comparing them with the results of models. Tables 1, 3 and 4 show the system parameters used for calculations [2; 5; 5; 9; 15; 42; 50] and [Proposed work].