## 4 Discussion and Conclusions
This set-up achieved a BER of 3.3259\(\times 10^{-5}\) at a distance of 72.5 cm between the LED and the PD, both situated in the passenger van, reaching a bit rate of 11.25 Mbps. The infrared link employs OOK with 8b10b encoding. As the data integrity requirements are less stringent than in the downlink, any packet lost due to interference is simply retransmitted, making this a suitable option. This uplink set-up reached a maximum data rate of 15.25 Mbps. In conclusion, a system capable of streaming UHD video was successfully implemented using the hardware design of the optical transceivers and optoelectronic interfaces executed in this work. Specifically, this system achieved a bit rate of 15.25 Mbps for OOK and 11.25 Mbps for QPSK within the OFDM scheme. For context, the system reported in [7] achieved up to 2 Mbps for video transmission using a red LED and reached an optical link of 50 cm, which is insufficient for UHD video transmission. In the work documented in [8], a data transmission speed of 0.986 Mbps was achieved over a distance of 5 m. However, a VLC system with this bit rate cannot support the UHD transmission rate targeted in this study. In [11], a maximum bit rate of 0.415 Mbps was reported, with video qualities ranging from 480p to 720p -far from the UHD focus of this work -. In [12], a system was developed with a bit rate of 7.14 Mbps over an optical link of 6.7 cm, while the optical link achieved in this work is 110 cm. Although [13] displayed an optical link of 100 cm, the bit rate reached was only 0.115 Mbps, inadequate for UHD video transmission. An optical link of 5 m with a bit rate of 0.115 Mbps was exhibited in [14], and [9] presented an optical link distance of 6 m with a bit rate of 0.986 Mbps. Both of these instances fall short of the requirements for UHD video transmission. Although [15] reported a UHD video transmission with a bit rate of 100 Gbps, the system utilized high-power lasers for Free Space Optical (FSO) Communication links. It is well known that high-power lasers are prohibited in environments where people are present due to the risk of inducing cornea injuries [5] and skin burns [6]. Therefore, the system outlined in [15] is unsuitable for user applications. Consequently, our proposed VLC system, capable of transmitting UHD video, remains the foremost option in the current state of the art for user applications. It is also compliant with the pre-existing lighting infrastructure in public transportation settings. A proof of concept was carried out by deploying the system in a passenger van, where it was successfully tested. Finally, a solar panel situated on the van's roof was employed to power the user's side, namely, the USB dangle and the user's laptop, through a power bank battery. With this set-up, the user's side was completely self-powered, charging the battery in 13.4 h under a luminous flux of 80,000 lx, while the battery life lasted 22.3 h.  
The terms abbreviation list can be found in the following Table 7.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/s24175829/s1](https://www.mdpi.com/article/10.3390/s24175829/s1)]([https://www.mdpi.com/article/10.3390/s24175829/s1](https://www.mdpi.com/article/10.3390/s24175829/s1)), Videos S1: Developed system in the lab, and deployed in a passenger van. **Author Contributions:** Conceptualization, C.I.d.V.M. and J.S.B.P. ; methodology, J.M.S.-P.; software, J.S.B.P. ; validation, J.S.B.P. and J.C.T.Z. ; formal analysis, J.S.B.P. and J.C.T.Z. ; investigation, C.I.d.V.M. and J.S.B.P. ; resources, C.I.d.V.M. ; data curation, J.S.B.P. ; writing--original draft preparation, C.I.d.V.M. and J.S.B.P. ; writing--review and editing, J.S.B.P., J.C.T.Z. and J.M.S.-P.; visualization, J.S.B.P. ; supervision, J.C.T.Z. and J.M.S.-P.; project administration, I.M.-S.; funding acquisition, I.M.-S. All authors have read and agreed to the published version of the manuscript.