Apparatus and method for transmitting and receiving data using visible light communication

1. An apparatus for transmitting and receiving data in a visible light communication system, the apparatus comprising:

a visible light communication (VLC) transceiver for converting a visible light signal received from a counterpart into an electrical signal and outputting the electrical signal, by using a light receiving device during a reception operation, and converting an electrical signal containing information into a visible light signal and transmitting the visible light signal to the counterpart, by using a light emitting device during a transmission operation;

a VLC controller comprising a visible frame engine (VFE) for generating a visible frame and outputting the visible frame to the VLC transceiver, in which the VFE generates the visible frame for transmission to a counterpart during non-transmission of respective frames for communication at a sender and a receiver in order to provide visibility to a communication link; and

a host controller for controlling the VLC controller and transmitting and receiving data to and from the VLC controller.

2. The apparatus of claim 1 , wherein the VLC controller comprises:

a transmission and reception (TRx) buffer for storing transmission data and received data for communication;

an 8B/10B encoder/decoder for converting a format of the transmission data into a format suitable for 8B/10B;

a serializer/deserializer for converting serial signals and parallel signals; and

a control register for receiving information required for controlling the VLC controller from the host controller, processing the received information, and providing information required for controlling the VLC controller.

3. The apparatus of claim 1 , wherein the frames for communication include a control frame, an acknowledge (ACK) frame, and a data frame.

4. The apparatus of claim 1 , wherein the host controller is connected with the VLC controller by using a central processing unit (CPU) interface.

5. A method for transmitting and receiving data in a visible light communication system, the method comprising:

transmitting, by a sender, a control frame for link control to a receiver;

receiving, by the receiver, the control frame and transmitting an acknowledge (ACK) frame to the sender to respond to the control frame;

transmitting, by the sender, a data frame containing information to the receiver; and

receiving, by the receiver, the data frame and transmitting an ACK frame to the sender to respond to the data frame,

wherein a visible frame is transmitted to a counterpart during non-transmission of respective frames for communication at the sender and the receiver in order to provide visibility to a communication link.

6. The method of claim 5 , wherein the visible frame is repetitively transmitted with a predetermined gap.

7. The method of claim 6 , wherein the predetermined gap is calculated using:

Visible Frame Gap Time=Visible Frame Length * Visible Threshold

where ‘Visible Frame Gap Time’ indicates a gap between visible frames, ‘Visible Frame Length’ indicates a length of the visible frame, and ‘Visible Threshold’ indicates a visible threshold value.

8. The method of claim 5 , wherein each of the control frame, the data frame, and the ACK frame is transmitted together with a digital preamble behind the digital preamble.

9. The method of claim 5 , wherein the length of the visible frame is set to a maximum of 32 Kbytes.

10. The method of claim 5 , wherein the visible frame comprises:

a preamble which is a signal having ‘1’ and ‘0’ repeated in a predetermined number of bits;

a start (STA) including a particular bit sequence to indicate a start of a frame;

an information (Info) block indicating information on a visible pattern block;

the visible pattern block defined as a code that is not used in an 8B/10B encoding scheme; and

a stop (STO) including a particular bit sequence to indicate an end of the frame.

11. The method of claim 10 , wherein the length of the preamble is set taking into account a time required for a clock-data recovery (CDR) of the receiver to recover a clock and data.

12. The method of claim 10 , wherein the length of the preamble is set to 10 bits.

13. The method of claim 10 , wherein the information block comprises information on a packet type part marking the visible frame, on a payload pattern part defining a pattern of a payload, and on a length part indicating a length of the visible frame.