## 4 Results and Discussion
By considering weak turbulence, a clear and widely opened eye pattern is observed for LG[0,0] over 25,000 km followed by the eye patterns for the LG[0,2], LG[0,4], and LG[0,8] modes, as depicted in Figure 5c-f.  
Figure 5: Eye diagrams for (**a**) no turbulence at 21000 km, (**b**) no turbulence at 30,000 km, (**c**) weak turbulence over 25,000 km at LG[0,0], (**d**) weak turbulence over 25,000 km at LG[0,1]], (**e**) weak turbulence over 25,000 km at LG[0,4], and (**f**) weak turbulence over 25,000 km at LG[0,8]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Turbulence**} & **LG[0,0]** & **LG[0,2]** & **LG[0,4]** & **LG[0,8]** \\ \cline{2-5}  & & & **km** & \\ \hline No & 30,000 & 30,000 & 30,000 & 30,000 \\ Weak & 24,500 & 24,000 & 26,000 & 24,000 \\ Medium & 24,500 & 23,800 & 22,000 & 22,500 \\ Strong & 23,500 & 22,000 & 21,500 & 22,000 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Maximum achieved range for different modes and wavelengths @ BER limit for satellite-to-ground communication. Figure 6a-d show the variation in BER values with the UWOC link range for different turbulences, water types, and operating modes. A maximum transmission range of 50 m is obtained for pure sea with a weak scintillation effect followed by the moderate and then the strong effects. Additionally, clear oceans perform the best, followed by coastal oceans, and harbor waters perform the worst at a log(BER) limit of \(-9\). Moreover, the LG[0,0] mode provides a superior performance in all cases over the other modes. For the LG[0,0] mode, the maximum transmission range is 19-27 m under all scintillation effects and in all types of water, as shown in Figure 6a. Additionally, for the LG[0,2] mode shown in Figure 6b, faithful transmission ranges of 26 m under weak, 20 m under moderate, and 18 m under strong scintillation effects are obtained for all types of water. According to Figure 6c, weak, moderate, and strong scintillation effects offer wireless ranges of 22-24 m, 16-18 m, and 13-15 m, respectively, at LG[0,4]. Figure 6d shows that, for the LG[0,8] mode, the weak, moderate, and strong scintillation effects achieve maximum ranges of 15-23 m, 13-15 m, and 12-14 m, respectively. In Tables 4-6, the results of the proposed system for ground-to-underwater communication under weak-to-strong scintillation effects are summarized for the different modes and water types. Figure 6: BER versus ground-to-underwater transmission range for operating modes of (**a**) LG[0,0], (**b**) LG[0,2], (**c**) LG[0,4], and (**d**) LG[0,8] under diverse scintillation effects. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Water Type**} & **LG[0,0]** & **LG[0,2]** & **LG[0,4]** & **LG[0,8]** \\ \cline{2-5}  & & \multicolumn{3}{c}{**m**} \\ \hline Pure sea & 25 & 18 & 15 & 14 \\ Clear ocean & 26 & 18 & 15 & 13 \\ Coastal ocean & 25 & 18 & 14 & 12 \\ Harbor & 25 & 18 & 13 & 12 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Maximum achieved range for different modes and wavelengths @ BER limit for ground-to-underwater communication under strong scintillation. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Water Type**} & **LG[0,0]** & **LG[0,2]** & **LG[0,4]** & **LG[0,8]** \\ \cline{2-5}  & & \multicolumn{3}{c}{**m**} \\ \hline Pure sea & 27 & 26 & 24 & 23 \\ Clear ocean & 27 & 26 & 24 & 20 \\ Coastal ocean & 27 & 26 & 23 & 17 \\ Harbor & 27 & 26 & 22 & 15 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Maximum achieved range for different modes and wavelengths @ BER limit for ground-to-underwater communication under weak scintillation. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Water Type**} & **LG[0,0]** & **LG[0,2]** & **LG[0,4]** & **LG[0,8]** \\ \cline{2-5}  & & \multicolumn{3}{c}{**m**} \\ \hline Pure sea & 26 & 20 & 18 & 15 \\ Clear ocean & 26 & 20 & 18 & 15 \\ Coastal ocean & 26 & 20 & 17 & 14 \\ Harbor & 26 & 20 & 16 & 13 \\ \hline \hline \end{tabular}
\end{table}