## 5 Results and Discussions  
In this section, we focus on evaluating the performance of the illumininance conditions of the mining environments. In addition, we analyze the characteristics of the proposed VLC mining channel through the RMS Delay Spread. Finally, we evaluate the performance of the ADR solutions proposed in the system VLC, specifically in \(R_{x}\) and applied in the two underground mining VLC scenarios, comparing them with a single PD, which is considered the baseline. This performance analysis is carry out and then discussed in terms of parameters, such as UDR, BER, and SINR based on an CDF. All evaluations are numerical and created with the use of simulations in Matlab software, in which the VLC scenarios were designed; comparisons are made between the proposed ADRs with their signal combining schemes and the single PD. The most relevant parameters used for the simulations development, with their respective values and references, can be seen in the Table 1.  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**System Model Parameters** & **Values** & **References** \\ \hline \multicolumn{3}{l}{**Mining roadway**} \\ \hline Dimensions (\(w\times l\times h\)) & \((2\times 10\times 3.7)\) m \\ Coordinates of the \(T_{x}s\) (\(x,y,z\)) & \(T_{1}=(0,3,3.5),T_{2}=(0,1,3.5),T_{3}=(0,-1,3.5),\) \\  & \(T_{4}=(0,-3,3.5)\) \\ \hline \multicolumn{3}{l}{**Mine working face**} \\ \hline Dimensions (\(w\times l\times h\)) & \((2\times 10\times 4.7)\) m \\ Coordinates of the \(T_{x}s\) (\(x,y,z\)) & \(T_{1}=(-0.5,-1.25,4.5),T_{2}=(0.5,1.25,4.5),\) \\  & \(T_{3}=(0.5,-1.25,4.5),T_{4}=(-0.5,1.25,4.5)\) \\ \hline \multicolumn{3}{l}{**Other parameters**} \\ \hline \multicolumn{3}{l}{**Channel parameters**} \\ \hline Absolute temperature & 295 K & [45] \\ AWGN power spectral density & \(2.5\times 10^{-23}\)A/Hz & [18] \\ Background dark current & 10 nA & [45] \\ Boltzmann constant & \(1.38\times 10^{-23}\)m\({}^{2}\) kg s\({}^{-2}\) K\({}^{-1}\) & [45] \\ Capacitance & \(112\times 10^{-8}\) F/m\({}^{2}\) (s\({}^{4}\) A\({}^{2}\) m\({}^{-4}\) kg\({}^{-1}\)) & [45] \\ Electronic charge & \(1.6\times 10^{-19}\) C & [45] \\ FET channel noise factor & 1.5 & [45] \\ FET transconductance & 0.03 S (kg\({}^{-1}\) m\({}^{-2}\) s\({}^{3}\) A\({}^{2}\)) & [45] \\ Noise bandwidth & 100 MHz & [45] \\ Noise bandwidth factor \(I_{2}\) & 0.562 & [45] \\ Noise bandwidth factor \(I_{3}\) & 0.0868 & [45] \\ \hline \multicolumn{3}{l}{**VLC transceiver parameters**} \\ \hline Average output optical power & 10 W & [19] \\ Band-pass filter of transmission & 1 & [9,16] \\ Gain of the optical filter & 1 & [23] \\ Helmet position & 1.7 m & \\ Modulation & OOK & [11] \\ Modulation bandwidth & 50 MHz & [11] \\ Modulation index & 0.3 & [19] \\ Number of \(R_{x}s\) & 1 & \\ Open-loop voltage gain & 10 & [45] \\ PD physical area & 1 cm\({}^{2}\) & [9,11,16] \\ Optical filter bandwidth & 340 nm to 694.3 nm & [48] \\ Optical filter center wavelength & 340 \(\pm\) 2 nm & [48] \\ Optical filter full width half max & 10 \(\pm\) 2 nm & [48] \\ Refractive index & 1.5 & [9,16] \\ Reflection coefficient & 0.8 & [9,11,16] \\ Responsivity & 0.53 A/W & [18,19] \\ Rx FOV & 60\({}^{\circ}\) & [9,11,16] \\ Tx semi-angle at half power & 60\({}^{\circ}\) & [18,19] \\ \hline \hline \end{tabular}
\end{table}
Table 1: Underground mining VLC system simulation parameters.