A Differential Demodulation Method Based on Color Shift Keying

Abstract

The invention discloses a differential demodulation method based on color shift keying, which includes recording the m-channel signals of the transmitting end according to the power P 1 , P 2 , P 3 ,...,P m The signal power received by the receiving end after the transmitted optical signal is attenuated by the channel is P 1r , P 2r , P 3r ,...,P mr ; Calculate the sum of the powers of the other circuits except the power of one circuit, denoted as P respectively 1r ’ , P 2r ’ , P 3r ’ ,...,P mr ’ ; Perform differential operation on the sum of the signal power of each channel and the power of other channels; establish an m-dimensional coordinate system, and each coordinate axis corresponds to P 1 , P 2 , P 3 ,...,P m The value of , can be divided into the following n cases, by P 11r ’ =0, P 22r ’ =0, P 33r ’ =0,...,P mmr ’ The (m-1)-dimensional graph represented by =0 divides the m-dimensional power domain into n equal parts, and according to the obtained power point P 1r , P 2r , P 3r ,...,P mr In the area where it is located, the corresponding symbols are mapped. This method improves the anti-interference ability of the wireless optical communication system and ensures the application requirements of high-speed communication.

Description

technical field [0001] The invention relates to the technical field of visible light communication, in particular to a differential demodulation method based on color shift keying. Background technique [0002] During the development of Visible Light Communication (VLC), the IEEE802.15.7 VLC discussion group proposed a new modulation method called Color Shift Keying (CSK). Red, green and blue (RGB) tri-color LEDs are used, which transmit data by changing colors rather than turning the lights on and off. The CSK system generally uses three colors as the base color to form a three-LED or T-LED system, and also has a four-LED system or a Q-LED system composed of four LEDs. Multiple LEDs increase the hardware complexity of the system. [0003] Since the luminous intensity of LEDs has a nonlinear relationship with the current, and the color change is achieved by the change of the power ratio of multicolor LEDs, Murata N, Kozawa Y and Umeda Y in IEEE Photonics Journal, Vol. 8, No...

AI Technical Summary

Problems solved by technology

However, with the increase of visible light communication rate, some problems are gradually exposed

For example, various interference factors in the transmission medium will cause the attenuation of optical energy and affect the communication distance, and the attenuation of different wavelengths of light in the same environment is different. In severe cases, it will cause a large deviation of the power point and cause demodulation to occur. mistake

Images