2020 | vol. 68 | nr. 2 | art. 9

Bidirectional Video Visible Light Communication

Arsyad Ramadhan DARLIS, Lita LIDYAWATI, Raden Jati TRIKUSUMO
Abstract
Video communication is needed for many applications used in both air and underwater environment, which require a bidirectional system during its transmission. Consequently, bidirectional video communication using visible light is essential. Recently, several communication technologies have been presented using various transmission mediums, i.e., radio frequency communications, acoustic communications, and visible light communications (VLC). VLC offers high data rates, a free spectrum, and it can be integrated with existing infrastructures, so VLC becomes promising technology for video communication both on the air and an underwater environment. Up to this stage, past studies on video communication are mostly done using a unidirectional method. In this study, a visible light-based bidirectional video communication is proposed. The system employs a bidirectional method where each of the Red, Green, and Blue (RGB) filters is utilized to represent respective wavelengths in each link. In link 1, a transmitter circuit transmits the video signal using a commercial white light-emitting diode (LED) through a colour filter to build unidirectional systems, which then received by photodiode (PD) arrays in the receiver circuit. The same system is used in link 2, where the video signal is transmitted from the transmitter circuit toward the receiver circuit through a colour filter, so the bidirectional systems is built. This proposed system was applied in bright and dark conditions. The measurement for the system was undertaken based on the distances of transmitter and receiver, as well as crosstalk measurement represented by the Near-End Crosstalk (NEXT) parameter. The results show that the video signal can be sent from the transmitter to the receiver at various distances using proposed systems. In bidirectional measurement, the video signal can be transmitted in two directions, where the best measurement results are obtained when the conditions of the two transmitters use different colour filters. It is a blue filter in link 1 and green filter in link 2, and then the red filter in link 1 and green filter in link 2. The other result shows the average voltage received during the experiment in the bright is higher than in the dark condition. The crosstalk measurement results show the NEXT parameter is only obtained when the systems utilize the same colour filter on both receivers. Therefore, for future use, the same wavelength in the bidirectional video communication system should be avoided. Based on those results, it is concluded that the system proposed in this study is a reliable bidirectional video communication system. We show that successful simultaneous high-quality video signal transmissions are possible without the need for optimized optics.
Keywords: Visible light communication (VLC), video, bidirectional, light emitting diode (LED), photodiode (PD)
To cite this article: DARLIS, A. R., LIDYAWATI, L., TRIKUSUMO, R. J., “Bidirectional video visible light communication,” in Electrotehnica, Electronica, Automatica (EEA), 2020, vol. 68, no. 2, pp. 85-92, ISSN 1582-5175.

 

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