Method and apparatus for reduced flicker visible light communications (VLC)

• US 10,038,501 B2
• Filed: 07/31/2017
• Issued: 07/31/2018
• Est. Priority Date: 09/18/2009
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Castor, Douglas R., Kaur, Samian, Liu, Weimin
• Primary Examiner(s): Singh, Dalzid
• Application Number:
  US15/664,886
• Publication Number:
  US 20170331552A1
• Time in Patent Office: 365 Days
• Field of Search: 398130
• CPC Class Codes: H04B 10/1143 Bidirectional transmission
• CPC Class Codes: H04B 10/1149 Arrangements for indoor wireless networking of information
• CPC Class Codes: H04B 10/116 Visible light communication
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H05B 47/195 the transmission using visible or infrared light

Abstract

A visible light communication (VLC) device for lighting and data transmission is disclosed. The VLC device may comprise circuitry configured to receive a first stream of bits and determine a first switchpoint for transmitting the first stream of bits and first filler data. The VLC device may further comprise red, green, and blue (RGB) light emitting diodes (LEDs) configured to transmit the first stream of bits and the first filler data in the visible light spectrum. The first filler data may begin to be transmitted at the first switchpoint. Similar to the first stream of bits, a second stream of bits may be received and transmitted by the RGB LEDs of the VLC device. In this way, a naked eye of a human may not detect flicker of the VLC device.

Claims

1. A visible light communication (VLC) device for lighting and data transmission, the VLC device comprising:

circuitry configured to receive a first stream of bits;

the circuitry further configured to determine a first switchpoint for transmitting the first stream of bits and first filler data, wherein the first filler data is based on a brightness level;

red, green, and blue (RGB) light emitting diodes (LEDs) configured to transmit the first stream of bits and the first filler data, wherein the first filler data begins to be transmitted at the first switchpoint;

the circuitry configured to receive a second stream of bits, wherein the second stream of bits is different than the first stream of bits;

the circuitry configured to determine a second switchpoint for transmitting the second stream of bits and second filler data, wherein the second filler data is based on the brightness level; and

the RGB LEDs configured to transmit the second stream of bits and the second filler data, wherein the second filler data begins to be transmitted at the second switchpoint;

wherein a naked eye of a human cannot detect flicker of the VLC device.

2. The VLC device of claim 1, wherein the circuitry is incorporated in a lamp.

3. The VLC device of claim 1, wherein the circuitry is incorporated in a traffic light.

4. The VLC device of claim 1, wherein bands of the RGB LEDs are multiplexed together and an overriding output color of the multiplexed RGB LEDs is white light.

5. The VLC device of claim 4, wherein a scrambling code is applied at each band of the bands of the RGB LEDs.

6. The VLC device of claim 1, wherein the circuitry is configured to band separate the first stream of bits prior to transmission by the RGB LEDs.

7. The VLC device of claim 1, wherein the circuitry is configured to band separate the second stream of bits prior to transmission by the RGB LEDs.

8. A method performed by a visible light communication (VLC) device for lighting and data transmission, the method comprising:

receiving a first stream of bits;

determining a first switchpoint for transmitting the first stream of bits and first filler data, wherein the first filler data is based on a brightness level;

transmitting, by red green and blue (RGB) light emitting diodes (LEDs), the first stream of bits and the first filler data, wherein the first filler data begins to be transmitted at the first switchpoint;

receiving a second stream of bits, wherein the second stream of bits is different than the first stream of bits;

determining a second switchpoint for transmitting the second stream of bits and second filler data, wherein the second filler data is based on the brightness level; and

transmitting, by the RGB LEDs, the second stream of bits and the second filler data, wherein the second filler data begins to be transmitted at the second switchpoint;

wherein a naked eye of a human cannot detect flicker of the VLC device.

9. The method of claim 8, wherein the RGB LEDs are incorporated in a lamp.

10. The method of claim 8, wherein the RGB LEDs are incorporated in a traffic light.

11. The method of claim 8, wherein bands of the RGB LEDs are multiplexed together and an overriding output color of the multiplexed RGB LEDs is white light.

12. The method of claim 11, wherein a scrambling code is applied at each band of the bands of the RGB LEDs.

13. The method of claim 8, wherein the circuitry is configured to band separate the first stream of bits prior to transmission by the RGB LEDs.

14. The method of claim 8, wherein the circuitry is configured to band separate the second stream of bits prior to transmission by the RGB LEDs.

15. A visible light communication (VLC) device comprising:

circuitry configured to determine a first switchpoint for receiving a first stream of bits and first filler data, wherein the first filler data is based on a brightness level;

a receiver configured to receive, from red green and blue (RGB) light emitting diodes (LEDs), the first stream of bits and the first filler data, wherein the first filler data begins to be received at the first switchpoint;

the circuitry configured to determine a second switchpoint for receiving a second stream of bits and second filler data, wherein the second filler data is based on the brightness level; and

the receiver configured to receive, from the RGB LEDs, the second stream of bits and the second filler data, wherein the second filler data begins to be received at the second switchpoint;

wherein a naked eye of a human cannot detect flicker of the RGB LEDs.

16. The VLC device of claim 15, wherein the RGB LEDs are incorporated in a lamp.

17. The VLC device of claim 15, wherein the RGB LEDs are incorporated in a traffic light.

18. The VLC device of claim 15, wherein bands of the RGB LEDs are multiplexed together and an overriding output color of the multiplexed RGB LEDs is white light.

19. The VLC device of claim 18, wherein each band of the bands of the RGB LEDs is scrambled.