Enabling Self-Powered Analog Voice Communication with Photovoltaic Cells and Optical Wireless Links Communication

The growing demand for energy-efficient communication systems has triggered the interest in using photovoltaic (PV) panels to power optical receivers in Visible Light Communication (VLC) systems. While this approach offers the enticing advantage of self-powered operation, it comes with a significant drawback of limited bandwidth. This limitation severely restricts the maximum data rate achievable through VLC channels, especially when compared to digital audio transmission which requires high bandwidth due to sampling and resolution needs. Therefore, a key challenge lies in finding a balance between the energy-harvesting benefits of PV receivers and the need for a sufficient data rate for specific VLC applications. This work evaluates experimentally the possibility to transmit using VLC the voice in the analogue domain when the transmission of the digital conversion of limited by the bandwidth of the PV-based receiver. The results show that speech can be received properly in analogue domain when the transmission of the digital conversion is not possible due to limited bandwidth of the PV panel. The results show that the PV panel is able to receive speech with cross-correlation factors above 0.94. On the other hand, a 128 KHz digital signal, that is transmitted over the same optical channel, is not visible at the receiver side.