Visible light communication using colour shift keying

Abstract

The present invention provides a visible light communication transmitter (13), a visible light communication receiver (14), a visible light communication system (2), and a method of visible light communication, wherein the transmitter, the receiver, the system and the method are suitable for colour shift keying (CSK), as well as providing a method of colour shift keying. The visible light communication transmitter (13) comprises at least six, preferably seven, and more preferably eight, graphene-based light emitting devices (LED-1, LED-2,... LED-8) of different peak transmission wavelengths from each other. The visible light communication receiver (14) comprises a corresponding number of graphene-based photodetectors (PD-1, PD-2,... PD-8) of different peak reception wavelengths from each other. A visible light communication system according to the invention comprises such a transmitter and such a receiver, wherein each respective one of the different peak reception wavelengths of the six graphene-based photodetectors corresponds to a respective one of the different peak transmission wavelengths of the graphene-based light emitting devices. Such a system allows a method of visible light communication, preferably using colour shift keying, with a colour constellation of at least six, maybe seven, or even eight base colours. These can provide an increased number of symbols, a reduced symbol error rate and an improved signal-to-noise ratio in comparison to traditional visible light communication systems for colour shift keying, which use a colour constellation of only three orfour base colours.

Description

[0001] The present invention relates to the visible light communication transmitter according to claim 1, the visible light communication receiver according to claim 6, the visible light communication system according to claim 11, the visible light communication method according to claim 12 and The color shift keying method according to claim 15. Background technique [0002] It is known to transmit information using visible light by encoding the information using constellations of different colors. This is called color shift keying (CSK). Prior art systems may use color constellations of three or four primary colors. Such a system can be implemented using LEDs of different colors, the number of said LEDs can be three, in which case the system is called a three-LED or T-LED system, or the number of said LEDs can be four, In this case the system is called a quad-LED or Q-LED system. For example, WO 2012 / 097885 describes coding schemes and methods for color shift keying const...

AI Technical Summary

Problems solved by technology

[0004] Furthermore, using only three or four primary colors limits the range of different possible color combinations achievable by mixing, and thus correspondingly reduces the number of different symbols that can be represented by colors using CSK

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