Communication link apparatus and method for maintaining visibility in visible light communication

• US 20090010654A1
• Filed: 07/07/2008
• Published: 01/08/2009
• Est. Priority Date: 07/06/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Jeong-Seok, Lee, Kyung-Woo, Shin, Hong-Seok, Jung, Dae-Kwang, Park, Sung-Bum, Shin, Dong-Jae, Hyun, Yoo-Jeong, Hyun, Seong Hoon
• Granted Patent: US 8,320,768 B2
• Time in Patent Office: Days
• US Class Current: 398/135
• CPC Class Codes: H04B 10/1143 Bidirectional transmission
• CPC Class Codes: H04B 10/116 Visible light communication

Abstract

A system and method for continuing a communication link while maintaining visibility in visible light communication. A frame is transmitted by a sender for establishing a communication link before data transmission to a receiver by a sender. A receiver sends a response frame that reports on establishment of the communication link prior to data transmission by the sender. A data frame containing information is transmitted by the sender to the receiver. An acknowledgment frame is transmitted to the sender in response to the data frame. A disconnect frame is transmitted by the sender which is acknowledged by the receiver. A visible sequence is transmitted during a time period when the sender and the receiver do not transmit respective frames for communication to maintain visibility between two devices that may be communicating otherwise by, for example, infrared communication.

Claims

1. A method for continuing a communication link while maintaining visibility in visible light communication, the method comprising:

(a) transmitting, by a sender, a frame for establishing a communication link with a receiver prior to transmitting data;

(b) receiving, by the sender, a response frame for reporting a response regarding establishing the communication link with the receiver prior to transmitting data;

(c) transmitting, to the receiver, a data frame containing information from the sender;

(d) receiving, by the sender, an acknowledge frame from the receiver in response to the data frame transmitted by the sender;

(e) transmitting, by the sender, a disconnect frame to the receiver;

(f) receiving by the sender, a disconnect acknowledge frame from the receiver in response to the disconnect frame transmitted by the sender; and

(g) transmitting a visible light sequence in a time period when the sender and the receiver are not transmitting respective frames for communication.

2. The method according to claim 1, wherein steps (a), (b), (c), (d), (e) and (f) are performed using an infrared communication protocol.

3. The method according to claim 1, wherein at least one of steps (a), (b), (c), (d), (e) and (f) transmit using an infrared communication protocol.

4. The method according to claim 1, wherein more than two of steps (a), (b), (c), (d), (e) and (f) transmit using an infrared communication protocol.

5. The method as claimed in claim 1, wherein the step (g) of transmitting the visible sequence comprises the sub-steps of:

(i) transferring a particular frame containing information to a Encoder/Decoder (EnDec) layer, the particular frame descending from an Infrared Link Access Protocol (IrLAP) layer;

(ii) transferring the visible sequence which does not contain information to the EnDec layer when no frame containing information descends from the IrLAP layer; and

(iii) transferring a frame containing information to the IrLAP layer, the frame ascending from the EnDec layer.

6. The method as claimed in claim 5, wherein the visible sequence differentiates frames by identifying distinguishing bit streams from a Beginning of Frame (BOF) and an End of Frame (EOF) for distinguishing between frames containing information from frames that do not contain information based on a difference in bit streams.

7. The method as claimed in claim 6, wherein the BOF and the EOF used repeatedly to distinguish frames containing information from frames that do not contain information.

8. A communication link apparatus for maintaining visibility in visible light communication, the communication link apparatus comprising:

a transceiver for transmitting a frame for establishing a communication link prior to data transmission, and for transmitting a data frame containing information, and a disconnect frame for disconnecting the communication link; and

wherein said transceiver for receiving a response frame regarding establishment of the communication link and an acknowledge frame regarding data being received by a sender, and

a visible sequence means for transmitting visible light during a time period of the communication link when the no frames are being transmitted or received.

9. The communication link apparatus as claimed in claim 8, wherein the communication link is provided with visibility by a visible light communication protocol layer added between an Infrared Link Access Protocol (IrLAP) layer and an Encoder/Decoder (EnDec) layer of an infrared communication protocol.

10. The communication link apparatus as claimed in claim 9, wherein the visible light communication protocol (VLCP) layer is activated during a device discovery function of the IrLAP layer, and the (VLCP) layer is deactivated during a disconnect function.

11. The communication link apparatus according to claim 8, wherein the transceiver is arranged in a sender device for establishing the communication link with a receiver device.

12. The communication link apparatus according to claim 8, wherein the transceiver includes means for communicating with an infrared communication protocol for transmitting:

(i) to establish the communication link, (ii) transmit and receive data frames, (iii) receive acknowledgement frames and (iv) transmit disconnect frames.

13. The communication link apparatus according to claim 8, wherein the transceiver communicates only by visible light communication.

14. The communication link apparatus according to claim 12, wherein the visible sequence means transmits a visible light sequence between items (ii) (iii) and (iv).

15. The communication link apparatus according to claim 11, wherein the visible sequence means transmits a visible light sequence in any time period where data is not transmitted between the sender device and a receiving device.

16. The communication link apparatus according to claim 8, further comprising a controller for differentiating frames by identifying distinguishing bit streams from a Beginning of Frame (BOF) and an End of Frame (EOF) to distinguish between frames containing information from frames that do not contain information, based on a difference in bit streams.