Abstract:
Disclosed herein is a method of performing visible-light wireless communication using light-emitting diode (LED) illumination, in which Variable Pulse Position Modulation (VPPM) is used for low-speed data transmission and dimming of illumination, and orthogonal frequency division multiplexing (OFDM) modulation is used in a VPPM on period for high-speed data transmission.
Abstract:
Disclosed herein is visible light communication technology having improved reception performance regardless of dimming control of lighting based on VPPM signals. A visible light communication apparatus includes a preamble generator for generating a preamble signal, a header generator for generating a PHY header, which includes information about the physical layer of a transmission packet and dimming information including the target dimming level of the transmission packet, a fixed dimming VPPM modulator for modulating the PHY header into a first VPPM signal according to a predetermined ratio, a transmission unit signal processor for generating transmission data by performing signal processing for data to be transmitted, a variable dimming VPPM modulator for modulating the transmission data into a second VPPM signal having the target dimming level of the transmission packet, and a signal synthesizer for forming the transmission packet by combining the first and second VPPM signals.
Abstract:
Disclosed herein are an apparatus and method for controlling a lighting network. The apparatus for controlling lighting network includes a control device and a plurality of control gears. The control device generates and transfers commands to control lighting. The plurality of control gears receives the commands from the control device and control lighting. The control device assigns a right to use a lighting network to the control gears, and the control gears send information about a change in a lighting state or error details to the control device using the right to use a lighting network.
Abstract:
Disclosed herein are an apparatus and method for sensing an error and a variation in Light-Emitting Diode (LED) lighting. In the method, a PWM signal including required light emission information is generated. Tail data including operation information is generated. A CRC value based on the tail data is also generated. A tail-CRC signal is generated by combining the tail data with the CRC value. Finally, a PWM-tail signal is generated by combining the tail-CRC signal with the PWM signal.
Abstract:
Disclosed herein are a visible light communication method and apparatus. The visible light communication method includes determining whether a current location is the start of a symbol of a transmission signal, setting a sample index, a signal accumulated value for an accumulation region of a front half portion of the symbol, and a signal accumulated value for an accumulation region of a rear half portion of the symbol, determining whether the sample index belongs to an accumulation region of the front or rear half portion of the symbol, and accumulating samples of the transmission signal in accordance with the location to which the sample index belongs, determining whether a current location corresponds to the end of the symbol, and outputting a Variable Pulse Position Modulation (VPPM) communication signal corresponding to the transmission signal.
Abstract:
Disclosed herein is an LED lighting control apparatus and method based on visible light communication. The LED lighting control apparatus includes lighting information collection means for collecting status information about lighting means and environmental information about surroundings of the lighting means, and transmitting the collected information to lighting control means. The lighting information collection means includes a visible light reception processing unit for receiving the status information about the lighting means contained in a visible light signal emitted from the lighting means, a lighting information analysis unit including a plurality of environmental information sensors for detecting the environmental information about the surroundings of the lighting means, the lighting information analysis unit analyzing the environmental information detected by the environmental information sensors, and a lighting information control unit for collecting the status information and the analyzed environmental information and transmitting the collected information to the lighting control means.
Abstract:
Provided are a pulse-matched filter-based packet detection apparatus and method. The packet detection apparatus includes a photoelectric converter for converting an optical wireless communication signal into an electrical signal, an analog-to-digital converter (ADC) for converting the electrical signal into a digital signal, a pulse-matched filter for outputting a first correlation representing a correlation between a pulse obtained by oversampling a modulated pulse and the digital signal, a correlator for outputting a second correlation representing a correlation between the first correlation and a preamble code, a packet detection signal generator for generating a packet detection signal by comparing the second correlation and a packet detection threshold value, and a demodulator for demodulating the digital signal based on the packet detection signal.
Abstract:
Disclosed herein are a method for recognizing a table for an electronic menu system based on visible light and an apparatus for the same. The method includes receiving, by a visible light receiver connected to a smart device provided to a customer in a restaurant, multiple visible light signals from multiple lamps installed in the restaurant; detecting at least one valid signal from the multiple visible light signals in consideration of the multiple visible light signals and sensor data collected from a sensor installed in the smart device; and recognizing a table at which the customer is sitting using table information included in the at least one valid signal.
Abstract:
An apparatus and a method for measuring a position of a light are disclosed. The apparatus for measuring a position of a light includes: an inputting unit configured to receive position information on a building and a floor in which a user is positioned; a position coordinate calculating unit configured to measure distances between a position of the user and wall surfaces in the building in each direction and calculate a position coordinate of the user based on the distances in each direction; a position determining unit configured to apply the position coordinate to a plan view corresponding to the position information to determine an initial position of the user; and a position information combining unit configured to receive a light identifier depending on movement of the user and store position information of the light corresponding to the light identifier.
Abstract:
Disclosed herein is a visible light communication method and device using a DMX-512 network. In the visible light communication method, dimming data packets are received. Visible Light Communication (VLC) data packets are generated. The dimming data packets and the VLC data packets are scheduled so that one or more of the VLC data packets are transmitted to Light Emitting Diode (LED) lighting devices connected over a Digital Multiplex (DMX)-512 network between transmission times of the dimming data packets.