## 3 Results and Discussion
For this model, the values of \(\alpha\) and \(\beta\) are set to 2. Figure 13 illustrates how the data transmission rate changes concerning the signal-to-noise ratio and transmitter power for BPSK, QPSK, 16 QAM, and 64 QAM modulations under the Gamma-Gamma distribution model. Figure 11: Variation in bit error rate as a function of transmitter power and SNR for 64 QAM modulation. Figure 12: The variations in data rate based on signal-to-noise ratio and transmitter power for BPSK, QPSK, 16 QAM, and 64 QAM modulations in foggy channel. This section uses the Rayleigh distribution for fading to model a wireless optical communication channel with high path loss. Due to the high path loss, the data transmission rate is severely reduced. Figure 14 shows the data transmission rate changes regarding the signal-to-noise ratio and transmitter power for Rayleigh fading for BPSK, QPSK, 16 QAM, and 64 QAM modulations. In an optical wireless communication channel affected by Rician fading, the K factor represents the ratio of the power of the direct-line-of-sight path to the power of the scattered paths. In this scenario, the K factor is set to 1. Figure 15 illustrates the data rate concerning the signal-to-noise ratio and transmitter power for Rician fading across BPSK, QPSK, 16 QAM, and 64 QAM modulation schemes. Figure 14: The data transmission rate changes regarding signal-to-noise ratio and transmitter power for Rayleigh fading for BPSK, QPSK, 16 QAM, and 64 QAM modulations. Figure 13: The data transmission rate changes concerning the signal-to-noise ratio and transmitter power for BPSK, QPSK, 16 QAM, and 64 QAM modulations under the Gamma–Gamma distribution model. In power allocation using embedded systems, the trained neural network assigns high power values to the transmitter for wireless optical communication channels characterized by low data rates and high bit error rates. It also considers low transmitter power values for channels with high data rates and a low BER. Figure 16 illustrates the variations in the data rate concerning the optimal power allocation predicted by the embedded system and the signal-to-noise ratio for the wireless optical communication channel under normal conditions across different OFDM modulation schemes. In the normal communication channel mode, the embedded power allocation system allocates a maximum power of 5.18 mW and a minimum power of 0.009 mW. Table 6 presents the maximum and minimum output power values from the embedded power allocation system for a normal wireless optical communication channel. Compared to the analytical power allocation system, this system has an average accuracy of 97%. The embedded system's average power allocation accuracy in an optical wireless communication channel impacted by fog is approximately 96%. In this scenario, the maximum power used in the optical wireless communication channel is 5.04 mW, with a data rate of 0.77 kbps. Its minimum value is 0.007 mW, occurring at a near-optimal data rate. Figure 17 illustrates the power budget allocated by the embedded system for various data rates and SNR values across different OFDM modulation schemes. The embedded power allocation system in optical wireless communication channels is less accurate than in other channels, particularly in conditions of smoke and fog. Table 7 presents the experimental system's output accuracy for various OFDM modulation schemes. It also displays the minimum and maximum power allocation values. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Modulation Scheme** & **Min Power (mW)** & **Max Power (mW)** & **Accuracy \%** \\ \hline BPSK & 0.009 & 5.18 & 95.88 \\ \hline QPSK & 0.0091 & 4.81 & 96.99 \\ \hline
16 QAM & 0.0098 & 4.96 & 98.56 \\ \hline
64 QAM & 0.0123 & 5.01 & 98.50 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Minimum and maximum values and accuracy of embedded power allocation system for OWC normal channel. Figure 15: The data rate concerning the signal-to-noise ratio and transmitter power for Rician fading across BPSK, QPSK, 16 QAM, and 64 QAM modulation schemes.