Abstract: An apparatus and method for transmitting and receiving data in one-to-one communication are provided. A first buffer for temporarily storing file data and a second buffer for temporarily storing message data are connected to a data transmitter for transmitting data and a data receiver for receiving data, respectively or vice versa, according to a request for data transmission or reception. The buffer for storing file data and the buffer for storing message data are differently constructed, thereby reducing the waste of memories of the buffers and achieving the miniaturization and high-speed data transmission of a portable terminal device.

Abstract: A display device for providing additional information using Visible Light Communication (VLC), including a decoder for dividing an input signal into a video signal and a data signal including additional information on at least one object included in an image output through the video signal; a display; a VLC controller for receiving the data signal from the decoder and encoding the data signal in accordance with a VLC protocol to output the data signal as a visible light signal through the VLC; light source blocks, which include light sources, back light the display, and output the data signal encoded in accordance with the VLC; and a control unit for controlling the encoded data signal including the additional information on the object, to be output as the visible light signal through a light source block at a position corresponding to the object from among the light source blocks.

Abstract: Provided is an apparatus and method for transmitting and receiving data in a visible light communication system, the apparatus including 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

Abstract: A passive optical network includes: a central office for generating multiplexed downstream optical signals and receiving an upstream optical signal; a plurality of optical network units for receiving a corresponding downstream optical signal and generating subcarrier channels carrying electrical data of an assigned frequency; and a remote node for photoelectrically converting the channels into electrical data, electro-optically converting the electrical data into at least one upstream optical signal.

Abstract: A Visible Light Communication (VLC) method in a VLC terminal, in which the VLC terminal requests initial access to an Access Point (AP) on a selected mini-slot among a plurality of mini-slots constituting a control slot, based on control information in a frame, sends an association request to the AP on an allocated uplink time slot, if the uplink time slot allocated to correspond to the selected mini-slot exists in control information in a next frame, and transmits data at a data rate appointed to the VLC terminal included in control information in the current frame using an association Identifier (ID) included in a response received in reply to the association request and the allocated uplink time slot.

Abstract: Disclosed is a color lamp driving apparatus for generating illumination light of various colors by using a plurality of Red (R), Green (R), and Blue (B) lamps together with each other, having a color controller for generating a color control signal, which indicates driving time rates of R, G, and B lamp arrays, according to color information of required illumination light, and a lamp driving module for outputting a driving signal for driving each of R, G, and B lamp arrays according to the color control signal output from the color controller. The driving signal is set to apply driving times for the R, G, and B lamp arrays based on one among a start time point, a middle time point, and an end time point of each corresponding period ?T within one light-emitting period T.

Abstract: Disclosed is an apparatus for controlling an illumination device for optical communication, including an optical array having a plurality of light emitting elements, a visible ray communication unit for outputting an electrical signal for visible ray communication, an optical array driving unit for providing a control signal for individually controlling ON/OFF of the plurality of light emitting elements, and a logic operation unit for performing logic operations on signals provided from the visible ray communication unit and the optical array driving unit, and outputting resultant operated signals to the optical array.

Abstract: Provided is a method of measuring the position of a portable terminal, comprising detecting indoor illuminating light, and outputting an electric signal corresponding to the detected indoor illuminating light, obtaining a plurality of data frames from the output electrical signal, and calculating a position of the portable terminal based on information regarding the position of a corresponding reference light source included in each data frame and an identifier corresponding to the reference light source included in said each frame and a reception time of said each data frame.

Abstract: An apparatus for transmitting visible light communication data is provided, the apparatus including a common modulation unit generating a modulated signal for transmitting a first visible light communication data, a plurality of individual modulation units generating modulated signals for transmitting a plurality of second visible light communication data, and a plurality of light emitting units receiving the modulated signals from the plurality of individual modulation units, respectively, and outputting visible light signals, wherein an output of the common modulation unit is the input as an output control signal of the individual modulation units.

Abstract: A data communication apparatus based on digital image processing is provided, in which a display displays a color block array including color blocks corresponding to transmission data, a camera captures an image of a color block array displayed on a display of a transmitting side, a storage stores a code table including information about colors mapped to data values, and a Digital Signal Processor (DSP) creates a color block array by converting transmission data to color blocks according to the code table during data transmission, and identifies the color block array in the image captured by the camera, detects colors of color blocks in the color block array, and extracts data values corresponding to the detected colors during data reception.

Abstract: Disclosed are an optical signal concentrator and an optical receiver for wireless optical communication. The concentrator includes a diffusion sheet and a light guide plate positioned below the diffusion sheet for guiding diffused optical signals perpendicularly to the incident direction the diffused optical signals, the light guide plate being formed with at least one concentric circle pattern facing the diffusion sheet. The receiver includes an optical signal concentrator including a diffusion sheet, a light guide plate positioned below the diffusion sheet for guiding the optical signals perpendicularly to the incident direction the diffused optical signals, one or more optical detectors for detecting light projected to the side of the light guide plate, and a reflection plate for reflecting light incident to the light guide plate.

Abstract: An apparatus and method for controlling the emitted color of visible light according to the current communication state in a visible light communication (VLC) device. The method includes storing one or more communication states and emitting colors that are correspondingly matched to the one or more communication states to indicate each of the various communication states. The VLC also checks, which can be based upon selection of a VLC mode, the current communication state and an emits a color that corresponds to the current communication state and emits the checked color of light to provide a visible light signal that indicates communication status to a user.

Abstract: A TDM PON including: an optical line terminal; a remote node including multiple secondary optical distributors connected to multiple optical network units; and the multiple optical network units generating and outputting a corresponding upstream optical signal. Each of the secondary optical distributors splits an upstream optical signal input from one of the optical network units connected thereto so as to generate split upstream optical signals and transmits one of the upstream optical signals to the optical line terminal, and transmits another upstream optical signal to a different optical network unit.

Abstract: Provided is a method for broadcasting visible light information in visible light communication. The method includes determining a time interval for a simultaneous signal and a time interval for an individual signal of information to be displayed on a display device; simultaneously modulating output signals of three Red-Green-Blue (RGB) Light Emitting Diodes (LEDs) making up one pixel, and transferring the modulated information to the display device; individually modulating output signals of the three RGB LEDs and transferring the modulated information to the display device; and displaying the modulated information for any selected one of the time interval for the simultaneous signal and the time interval for the individual signal.

Abstract: A reconnection method and device for a peripheral interface using VLC provide a protocol for when a communication link between a primary device and a secondary device is disconnected. The primary device generates an R-XID message including reconnection information and a warning indication signal indicating the disconnection. The secondary device aligns the communication link with the primary device using the warning indication signal, receives the R-XID message from the primary device by the secondary device, and transmits an R-XID response message for the R-XID message to the primary device.

Abstract: A method for generating a visible signal for a data transmission frame in a visible-light communication system includes: receiving specific data constituted by a plurality of frames from a sender; checking and converting a received signal strength indication (RSSI) signal measured from the sender; whenever each frame of the specific data is consecutively received, checking the converted RSSI, determining a level of a visible signal for distinctively displaying a state of a corresponding communication channel, and transmitting the level of the visible signal to the sender; and when reception of the specific data has finished, transmitting a corresponding response message to the sender, according to whether the specific data has been successfully received.

Abstract: A wireless communication method between mobile terminals using visible light and a mobile terminal therefore are disclosed. The method includes: periodically transmitting device discovery signals for searching for a visible light communication device when there is a request for a visible light communication; transmitting only reference clock signals between the device discovery signals; and connecting a link to a receiving terminal to transmit data when a response signal for the device discovery signal is received from the receiving terminal.

Abstract: A method of providing a visible light communication in a data link layer of a visible light communication system adopting an infrared communication link connection protocol includes: broadcasting a discovery exchange station identification (D-XID) frame; generating a visible frame to provide a visibility to a link for a specified waiting time period for responding to the broadcast D-XID frame; exchanging a set normal response mode (SNRM) frame and an unnumbered acknowledgement (UA) frame for requesting a link setting between the transmitting and receiving terminals; generating visible frames for a waiting time for receiving the SNRM frame and the UA frame; exchanging an information transfer frame (I-frame) and a receive ready (RR) frame, which is a response to the I-frame, between the transmitting and receiving terminals; and generating visible frames for a specified waiting period for receiving the I-frame and the RR frame.

Abstract: A method and apparatus for arranging communication links in visible light communication increases the user visibility of the system. The method includes the steps of: (a) synchronizing, by a visible light communication (VLC) exchange identification (XID) frame, (b) transmission timing of a primary device and a secondary device in an allocated time slot, and securing time so as to allow the primary device and the secondary device to perform an operation required for transmitting data; (c) transmitting an XID command frame from the primary to the secondary device and (d) transmitting an XID response frame from the secondary receiving the XID command frame to the primary; and (e) filling remaining space of the allocated time slot with a visibility field so as to increase visibility of the remaining space of the allocated time slot after receiving the XID command frame or the XID response frame.

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.