VISIBLE RAY COMMUNICATION SYSTEM AND METHOD FOR TRANSMITTING SIGNAL

• US 20110229147A1
• Filed: 11/24/2009
• Published: 09/22/2011
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yokoi, Atsuya
• Granted Patent: US 9,276,676 B2
• Time in Patent Office: Days
• US Class Current: 398/172
• CPC Class Codes: H04B 10/116 Visible light communication

Abstract

A visible ray communication system and method that improve transmission rate and remove an influence of inter-color interference to improve the communication quality. A transmission apparatus included in the visible ray communication system allocates each carrier signal component of an OFDM signal, which is modulated into transmission information, to a plurality of LEDs of different colors. The information is added to a combination of a carrier frequency and an LED wavelength, when a carrier signal is allocated to an, in addition to each carrier signal being modulated into the information.

Claims

1-5. -5. (canceled)

6. A visible ray communication system, comprising:

a transmission apparatus including;

a plurality of light emitting devices for emitting light of different colors;

a serial-to-parallel convertor for serial-to-parallel converting serial transmission data into N parallel data signals and a control signal;

a modulator for generating N modulation signals by modulating the N parallel data signals output from the serial-to-parallel convertor;

a sine wave signal multiplier for generating N carrier signals by respectively multiplying the N modulation signals by N sine wave signals having an orthogonal carrier frequency;

a carrier allocation unit for receiving the N carrier signals and the control signal, allocating the N carrier signals to the plurality of light emitting devices based on the control signal, adding carrier signals allocated to same light emitting devices, and generating a transmission signal for each of the plurality of light emitting devices; and

a light emitting controller for controlling each of the plurality light emitting devices to emit light at a light emitting strength according to a signal amplitude of its respective transmission signal; and

a reception apparatus including;

a plurality of light receiving devices for receiving the light of the different colors and outputting a reception signal of each color;

a Fast Fourier Transform (FFT) unit for FFT processing the reception signals output from the plurality of light receiving devices using the N sine wave signals to extract the N modulation signals;

a demodulator for demodulating the N modulation signals extracted to restore the N parallel data signals;

a restoration unit for detecting a relationship between a carrier signal and a light emitting device of each color based on the N modulation signals and restoring the control signal from the N modulation signals; and

a parallel-to-serial convertor for parallel-to-serial converting the N parallel data signals and the control signal to restore the serial transmission data,

wherein N is a positive integer.

7. The visible ray communication system as claimed in claim 6, wherein the carrier allocation unit comprises:

N switches, each including an input port to which each carrier signal is input and a plurality of output ports corresponding to the plurality of light emitting devices, respectively, for switching an output destination of each of the carrier signals input to the input port to any of the output ports;

a switch controller for controlling each of the N switches based on the control signal and controlling the output destination of the carrier signals input to each of the N switches; and

a plurality of adders for adding the carrier signals output from the output port corresponding to the same light emitting devices for the N switches, the plurality of adders being same in number as the plurality of light emitting devices.

8. The visible ray communication system as claimed in claim 6, wherein the carrier allocation unit allocates carrier signals such that a same carrier signal is not allocated for different colors.

9. The visible ray communication system as claimed in claim 6, wherein the restoration unit comprises:

a signal determination unit for determining if each of the N carrier signals is included in the reception signal of each color; and

a combination detection unit for detecting combinations of each of the colors and carrier signals based on a determination result in the signal determination unit and restoring the control signal from a corresponding combination.

10. A method for transmitting a signal in a visible ray communication system, comprising the steps of:

serial-to-parallel converting, by a transmitter including a plurality of light emitting devices, serial transmission data into N parallel data signals and a control signal;

modulating the N parallel data signals to generate N modulation signals;

generating N carrier signals by multiplying the N modulation signals by N sine wave signals having an orthogonal carrier frequency, respectively;

allocating the N carrier signals to the plurality of light emitting devices based on the control signal;

adding carrier signals allocated to a same light emitting device;

generating a transmission signal for each of the plurality of light emitting devices;

controlling each of the plurality of light emitting devices to emit light in a light emitting strength according to signal amplitude of its transmission signal;

receiving, by a receiver including a plurality of light reception devices, the emitted light of different colors;

Fast Fourier Transform (FFT) processing a reception signal output from each of the plurality of light receiving devices using the N sine wave signals to extract the N modulation signals for each color;

demodulating the N modulation signals to restore the N parallel data signals;

detecting a relationship between each of the N carrier signals and the plurality of light emitting devices of each color based on the N modulation signals;

restoring the control signal based on the relationship; and

parallel-to-serial converting the N parallel data signals the control signal to restore the serial transmission data.