## 5 MCS Work Survey
This indicates that the medium's inhomogeneity in a real channel system seems critical. Some studies have investigated techniques considering the ocean surface's reflection, absorption, and scattering effects in various UOWC channel configurations. For instance, the research detailed in [128] presented a UOWC mathematical model that includes both LOS and NLOS links and considers the impact of incident light angles in pure seawater. Their proposed theoretical framework closely matched MCS, suggesting that their model accurately accounted for differences in received light powers across multiple alignment channels. These differences often affect the SNR and BER performance of UOWC channels. The same research team created the NLOS UOWC model, which considers realistic ocean wave surfaces [129]. They tested the model's efficacy using MCS, evaluating the received signal optical power and SNR varying wave surfaces caused by varied wind speeds. Furthermore, they demonstrated the beneficial effect of the Multiple-Input Multiple-Output (MIMO) principle in reducing the impact of large wavy surfaces. Most MCS studies employing UOWC channel modelling have appropriately evaluated particle attenuation while not considering turbulence-induced absorption and scattering effects, resulting in an underestimation of attenuation. However, the study in [131] examined the absorption and scattering effects induced by suspended particles and ocean turbulence, which significantly impact optical signal transmission. The methodology involved simulating the channel characteristics using MC methods and analysing parameters such as PL, CIR, and PDF of light intensity. Additionally, a study's authors [132] proposed the MCS approach for modelling optical underwater turbulence while taking absorption and scattering into consideration for diverse water types. This approach evaluated the channel in two ways: turbulent statistics under various conditions and stationary channel characteristics. Their findings emphasised the need not to separate turbulence from absorption and scattering when effectively modelling a UOWC channel. Table 9 summarises some selections of works on UOWC channel modelling. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Year** & **Modelling Approach** & **Link Configuration** & **Water Type** & \ \begin{tabular}{c} **Channel Characteristics** \\ \end{tabular}  & \begin{tabular}{c} **Transmitter** \\ **Characteristics** \\ \end{tabular}  & **Ref. ** \\ \hline
2005 & BLL & LOS & Pure sea, clear ocean, turbid and gulf water & PL & \(\lambda=532\) nm & [118] \\ \hline
2016 & BLL & PIT-LOS & Clear ocean water & PL & \(\lambda=532\) nm & [119] \\ \hline
2018 & Modified & LOS & Pure sea, clear ocean, coastal water, and harbor water & PL & \begin{tabular}{c} A semi-collimated \\ laser \\ \end{tabular}  & [120] \\ \hline
2008 & Analytical RTE & LOS & Pure sea, clear ocean, coastal and harbor water & PL & \(\lambda=532\) nm & [12] \\ \hline
2015 & Numerical RTE & NA & Coastal, harbor I water, and harbor II water & PL & NA & [103] \\ \hline
2018 & Numerical RTE & NA & Coastal, harbor I water & PL & NA & [121] \\ \hline
2019 & Numerical RTE & NA & Harbor I and harbor II water & PL & NA & [122] \\ \hline
2014 & \begin{tabular}{c} Stochastic \\ model \\ \end{tabular}  & LOS & Coastal water & NA & \(\lambda=532\) nm & [24] \\ \hline
2015 & \begin{tabular}{c} Stochastic \\ model \\ \end{tabular}  & LOS & Clear, turbid, coastal, and harbor water & NA & \(\lambda=532\) nm & [26] \\ \hline
2015 & \begin{tabular}{c} Stochastic \\ model \\ \end{tabular}  & LOS & Coastal and harbor water & PL & \(\lambda=532\) nm & [25] \\ \hline
2016 & \begin{tabular}{c} Stochastic \\ model and \\ log-normal \\ turbulence model \\ \end{tabular}  & \ \begin{tabular}{c} MISO \\ \end{tabular}  & \begin{tabular}{c} Seawater \\ \end{tabular}