Abstract: A cell-planning method for a wireless optical communication system includes: implementing a target region for constructing a wireless optical communication system as a virtual space; disposing a virtual light source within the virtual space; checking a sequence number of a virtual light ray generated by the virtual light source; checking the number of intersection points occurring between the virtual light ray, the sequence number of which has been checked, and surfaces of virtual objects, and comparing the number of intersection points of the virtual light ray with an allowable number of intersection points; storing the virtual light ray when the number of intersection points of the virtual light ray is greater than the allowable number of intersection points; and comparing the sequence number of the virtual light ray with a set number of virtual light rays.

Abstract: Disclosed is a method for transmitting data in a wireless visible light communication system, the method including the steps of transmitting a pilot signal for obtaining channel state information according to each channel from a transmitter to a receiver, and transmitting a pilot response signal containing channel state information according to each channel from the receiver to the transmitter; controlling, by the transmitter, a data rate according to the pilot response signal, transmitting, by the transmitter, data to the receiver, with data rate information inserted into a header and controlling, by the receiver, a data rate according to each channel by making reference to data included in the header information.

Abstract: A method and apparatus for providing additional information included in a video displayed on a display device using visible light communication (VLC). A data packet including video data and additional information for an object included in the video data is received. The video data is extracted from the data packet, and the video data is decoded. The additional information from the data packet is extracted, and the additional information decoded. The decoded video data is output through the display device, and at the same time, the additional information is transmitted for a particular object included in a video based on a VLC protocol using a light emitting device prepared in the display device. The additional information providing apparatus includes an image sensor module, a display module, a visible light receiving module, an additional information manager and a controller.

Abstract: A system and method for providing an in-building navigation service using VLC are provided, in which transmitters control lamp modules to generate visible light signals each in a combination of different wavelengths as information for a navigation function, a mobile terminal receives visible light signals from a plurality of lamp modules that illuminate an area where the mobile terminal is located, location information about a current location of the mobile terminal is acquired through the visible light signals received from the plurality of lamp modules, and navigation information including information that matches the location information to map information is displayed on the mobile terminal.

Abstract: Method and device for exchanging messages in a VLC navigation system is provided, in which a map server generates a provision message in the form of visible light signals through all lamps in an area, using a PLC network, where a navigation service is provided, a terminal that wants to implement the navigation service among terminals that have received the provision message transmits a registration request message to the map server, the map server transmits a registration response message for the registration request message to the terminal, the terminal transmits a map request message including information about a destination to the map server, the map server transmits a map response message including information about a path to the destination to the terminal, and the terminal displays map information and the path.

Abstract: A visible light receiver and method for a visible light communication system. A PD array converts a received optical signal to an electrical signal, a position controller outputs a control signal to adjust the position of the PD array according to values of signals output from PDs of the PD array, so that a highest output is from a predetermined area of the PD array A driving motor adjusts the position of the PD array according to the control signal received from the position controller, and a summer sums the values of the signals received from the PDs. A demodulator demodulates the output from the summer, and a decoder decodes the output of the demodulator.

Abstract: A method for transmitting/receiving data between first and second terminals in which data can be transmitted flexibly in each particular situation, i.e. according to the network environment of terminals between which visible light communication occurs, including the type and characteristics of transmitted data. The method includes the steps of: (a) connecting a communication link between a first terminal supposed to transmit data and a second terminal supposed to receive data; (b) determining a data transmission rate to be used for data communication; (c) allocating a transmission channel of a specific band within a frequency band enabling wireless communication; (d) establishing a data transmission environment based on consideration of the transmission rate and the transmission channel; and (e) conducting data communication between the first and second terminals with reference to the data transmission environment.

Abstract: Disclosed is a method for processing incoming signals of photo-detectors in a visible light communication system. The method includes: dividing symbol duration into divided durations according to an equal time interval to set the divided durations to a plurality of time slots, the symbol duration being a time required to transmit one of a symbol and a bit; receiving visible light signals through a photodiode array in a receiver; determining a gain value of each of the photodiodes during a time slot, in consideration of each photodiode area on the photodiode array during the time slot and the time slot position within the symbol duration; multiplying a gain value of each of the photodiodes by an output value of a corresponding photodiode; and summing up output values of each of the photodiodes by which the gain value has been multiplied and calculating a total of output values of the time slot.

Abstract: An apparatus and method for continuously providing a selected service being watched when a user moves out of a cell or network in a Digital Video Broadcasting-Handheld (DVB-H) Convergence of Broadcasting and Mobile Service (CBMS) system. Information required for a handover is provided to a terminal using an interactive channel. The handover for the terminal can be performed using a conventional scheme and an enhanced scheme even when the user moves to a new cell while watching the selected service. As the enhanced handover scheme is provided, the user can receive a seamless service. In a mobile environment, a handover scenario for the terminal can be efficiently provided.

Abstract: A wireless visible light communication system is provided. The system includes optical transmitters and optical receivers for receiving optical signals, wherein each of the optical transmitters includes a first light source for generating an optical signal, and at least one light source capable of generating light which has a color equal to that of the optical signal, and has a wavelength different from that of the optical signal.

Abstract: A navigation system and a navigation method inside of a building using Visible Light Communications (VLC) are provided. The navigation system includes a map server, in which map information required to provide a navigation function is stored, for transferring the map information to each lamp, a plurality of lamps, installed in each zone inside of the building and having their respective identifiable and unique IDentifications (IDs), for receiving the map information required to provide the navigation function from the map server, and for generating a visible light signal in response to the received map information by using a VLC module, and a mobile terminal, equipped with a visible light Rx module, for being provided with the map information upon receiving the visible light signal generated from the lamp, and for displaying a map image in response to the provided map information.

Abstract: A method and an apparatus for correcting a color imbalance of visible light in wavelength division parallel visible light communications (VLC). The method includes the steps of: transmitting a visible light signal including information from a VLC transmitter to a VLC receiver during a preset correction unit, and setting correction bits corresponding to a basis for correcting a color imbalance by each of wavelengths of the VLC transmitter. A generating of a first adjustment light corrects the color imbalance between the wavelengths from the VLC transmitter during a preset color adjustment period, and generating of a second adjustment light corrects a color imbalance between a previous correction unit and a current correction unit from the visible light communication transmitter.

Abstract: Disclosed is a method and an apparatus for correcting a color imbalance of visible light in wavelength division parallel visible light communications. The method includes the steps of: inverting an original signal including information by a visible light communication transmitter; transmitting the original signal including the information and an inverted signal from the visible light communication transmitter to a visible light communication receiver, receiving the original signal including the information and the inverted signal by the visible light communication receiver, reinverting the inverted signal among the received signals by the visible light communication receiver, restoring the inverted signal back to its state prior to the inversion by reinverting the inverted signal by the visible light communication receiver, and performing a diversity combination on the original signal and a restored signal.

Abstract: An optical receiver for visible light communication includes a lens system for converging visible light for light communication and an optical filter for passing converged visible light to the optical receiver. A photoelectric transmission device detects data from visible light for light communication in a VLC system. An optical filter is positioned between the lens system and the photoelectric transmission device, the optical filter having a first film for transmitting visible light and a second film arranged/grown around the first film to transmit ultraviolet rays or infrared rays. A first optical detects data from visible light passing through the first film of the optical filter. A second optical detector detects the intensity of light transmitting the second film. The encoding, encoding rate or intensity of the optical transmitted signal can be adjusted in response to the detection of at least the second optical detector.

Abstract: Disclosed is a method for setting a power control initial value by using an indication light in visible light communications and a transmission/reception (Tx/Rx) apparatus using the method. The method includes the steps of: radiating multiple indication lights having power levels different from one another by a visible light communication transmitter; aligning a communication position simultaneously with measuring Received Signal Strength Indication (RSSI) of the indication light on detecting the indication light, selecting a power level whose RSSI is in a preset threshold range and which is adequate for transmission/receive among the multiple power levels different from one another, and informing the visible light communication transmitter of the adequate power level by a visible light communication receiver; and transmitting data from the visible light communication transmitter to the visible light communication receiver by using a transmitted power initial value according to a selected power level.

Abstract: A peer-to-peer communication method for NFC is provided. A link-level security is started by exchanging a link-level security request and a link-level security response between an initiator terminal and a target terminal, then transmission data are encrypted at link-level security layers of the initiator terminal and the target terminal, and the encrypted data are exchanged between the initiator terminal and the target terminal. The link-level security is released by exchanging a link-level security release request and a link-level security release response between the initiator terminal and the target terminal.

Abstract: A beam-forming apparatus and method for improving system performance using a spatial interpolation and at least one Angle of Arrival (AoA) in a system based on regular spatial sampling is provided. The AoA is estimated using a carrier-to-interference ratio. Beam-forming angles are distributed and steered in a predefined scheme such that an identical process is applied in all directions. According to this steering, a linear system model is computed based on regular spatial sampling using regular spatial separation at beam angles. Beam-forming performance is improved by compensating for a difference between adaptive and sector-type arrays. Only the steps of computing a spatial interpolation and determining an angle range for beam-forming using at least one AoA are added. The precision of estimating an AoA and the precision of beam-forming increase without an additional antenna. Because the system is simpler than that of an adaptive beam-forming system, significant gain is obtained.

Abstract: A method for providing a broadcast service to a terminal by a network in a Digital Video Broadcasting-Handheld (DVB-H) Convergence of Broadcasting and Mobile Service (CBMS) system. The method includes generating Program Specific Information/Service Information (PSI/SI) indicative of information related to a broadcast service requested by the terminal; generating mapping information for information on the broadcast service in an Internet Protocol (IP) platform from which the terminal is currently receiving the broadcast service, and for information on a broadcast service corresponding to the broadcast service in IP platforms other than the IP platform; and including the generated mapping information in an IP/Medium Access Control (MAC) Information Notification Table (INT) of the PSI/SI, and delivering the INT to the terminal.

Abstract: Disclosed is a DVB-H CBMS system by which a user can continue to view a program being in service even when the transport stream or IP platform changes while the user views the program. In the DVB-H CBMS system, the system transmits service mapping information according to transport streams or IP platforms to the terminal, so that the system can provide a service without interruption to the terminal even when a user of the terminal moves out of a current cell or network into a new cell or network while receiving a service that the user selected.

Abstract: An apparatus and method for enabling a terminal to continuously receive an on-going service even when the terminal moves out of a serving cell or a home network in a DVB-H CBMS system are provided, in which a network controls a handover, designates a target cell for the terminal if the terminal is to perform the handover on an interactive channel, and when needed, processes the handover over an interactive network.