## 6 Results and Discussion
### Bit Error Rate for Different Bias Sensitivity  
Table 4 presents the BER results for the different bias sensitivity values and the 12 best-performing pixels. As discussed in Section 3.2, the bias sensitivity set the refractory period and threshold contrast sensitivity, influencing the capabilities of the OCC link. For the \"default\" bias sensitivity value, 4 pixels received data without errors, while for the \"High\" and \"VeryHigh\" values, 8 and 12 pixels showed an error-free reception, respectively. The performance of the subsequent pixels degraded rapidly. This indicates that higher bias sensitivity values for the receiver enhanced the OCC link performance, due to smaller values of the refractory period and threshold sensitivity. This configuration allowed the receiver to capture more events than when using smaller values; therefore, in a controlled and non-noisy environment (in the absence of external light sources, or movement), it yielded better results. The same behavior occurred for the other experimental setup parameters. In Table 5, we present the total number of events gathered for the different values of bias sensitivity. Higher values resulted in capturing more events, with a similar trend observed for the central duty cycle values. While these findings might imply that OCC systems benefit from increased bias sensitivity, there are significant drawbacks in real-world scenarios. The presence of noise from external light sources or movement can rapidly increase the number of events captured by the receiver. Consequently, the bus output may saturate, as detailed in Section 5.1, introducing undesirable delays and struggling to manage all pixel requests. This, in turn, could exacerbate the negative effects of the refractory period, degrading the overall system performance. \begin{table}
\begin{tabular}{c c c c} \hline
**Pixel** & **BS: “Default”** & **BS: “High”** & **BS: “VeryHigh”** \\ \hline p1 & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p2 & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p3 & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p4 & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p5 & \(1.67\times\)\(10^{-3}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p6 & \(1.20\times\)\(10^{-1}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p7 & \(1.87\times\)\(10^{-1}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p8 & \(2.84\times\)\(10^{-1}\) & \(<\)1.25 \(\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p9 & \(4.57\times\)\(10^{-1}\) & \(7.16\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p10 & \(4.58\times\)\(10^{-1}\) & \(9.53\times\)\(10^{-4}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p11 & \(4.63\times\)\(10^{-1}\) & \(4.76\times\)\(10^{-2}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ p12 & \(4.66\times\)\(10^{-1}\) & \(1.52\times\)\(10^{-1}\) & \(<\)1.25 \(\times\)\(10^{-4}\) \\ \hline \end{tabular}
\end{table} 
Table 4: The bit error rate was evaluated for various receiver bias sensitivity values, with a distance of 200 cm between the transmitter and receiver. The transmitter operated at a frequency of 100 Hz and a light stimulus irradiance of 13 Lux. For the n-pulse modulation, a duty cycle (\(D\)) of 0.4 was applied, with a maximum number of pulses (\(n_{\text{max}}\)) set to 4.