Abstract:
A data transmission device in a wireless visible light communication system and a method thereof are provided to distribute data rates according to SNRs(Signal to Noise Ratios) of each wavelength as controlling power ratios of each wavelength, thereby supporting maximum data rates. A pilot signal is transmitted to a receiver from a transmitter(601). The receiver transmits a pilot response signal to the transmitter(603). The transmitter controls a data rate according to the pilot response signal(605). The transmitter loads information about the data rate on a header, and transmits data(607). The receiver controls the data rate according to each channel by referring to the data rate information of header information. The pilot signal is transmitted to the receiver from the transmitter in order to find out state information of each channel.
Abstract:
A navigation system and a method thereof are provided to perform navigation functions by using visible light communication in a building where GPS signals cannot be received. A navigation system using visible light communication in a building comprises the followings: a map server(601) which stores map information for providing navigation functions, and then transmits the information to each lamp; the lamps which are installed in each region within the building, receives the map information from the map server, and then generates the information received as visible light signals by using the visible light communication; and a mobile terminal(606) which includes a visible light receiving module to receive the visible light signals generated from the lamps, and displays a map image corresponding to the provided map information.
Abstract:
본 발명은 휴대형 디지털 비디오 방송 (DVB-H: Digital Video Broadcasting) 방통융합 서비스 (CBMS: Convergence of Broadcasting and Mobile Service) 시스템에서 사용자가 이동을 해서 자신이 속해있는 셀(cell) 혹은 네트워크를 벗어난 경우에도 선택해서 시청하고 있는 서비스를 계속해서 제공받을 수 있도록 해주는 장치 및 방법을 제안한다. 본 발명에서는 인터렉티브 채널(Interactive Channel) 을 이용해 핸드오버를 하려는 단말기에게 필수적인 혹은 유용한 정보를 전달한다. 따라서 사용자가 자신이 선택한 서비스를 시청하면서 이동을 하여 새로운 셀에 들어가게 되어도, 단말기가 종래 방식과 강화된 방식을 이용해서 핸드오버를 수행할 수 있도록 해준다. 이러한 강화된 핸드오버 방식을 제공함으로써 본 발명은 사용자에게 끊김 없는 서비스를 제공할 수 있다. 또한 이동 환경에서 단말기의 핸드오버 실행 시나리오를 제공한다. 핸드오버, passive 핸드오버, 휴대형 디지털 비디오 방송 (DVB-H: Digital Video Broadcasting-handheld), 방통융합 서비스(CBMS: Convergence of Broadcasting and Mobile Service)
Abstract:
A visible light color imbalance correcting method during wavelength division parallel visible light communication and a device therefor are provided to be applied to the wavelength division parallel visible light communication, thereby obtaining a diversity gain through time diversity as conducting parallel transmission using wavelength division. A visible light communication transmitter starts data transmission to a visible light communication receiver(510). The transmitter transmits an original signal passing through the first path together with a signal passing through the second path, which reverses the original signal and delays the first time slot(520). The receiver receives a receiving signal(530), and separates the signals from each other to recover the signal passing through the second path(540). The original signal passing through the first path is diversity-combined with the recovered signal(550). The signal is restored(560).
Abstract:
A method for setting an initial power value using indication light in visible light communication and a transmitting/receiving device using the same are provided to allow a user to recognize and fine an indication light easily by making the indication light blink. A visible light communication transmitter(401) aligns positions of a transmitter and a receiver at an early stage of communication and generates a plurality of indication light each having a different power level to set a transmission power initial value, and transmits data to a visible light communication receiver(402) by using a transmission power initial value according to a power level selected by the visible light communication receiver. The visible light communication receiver checks the indication light transmitted from the visible light communication transmitter, aligns its communication position, measures a receive strength of the indication light, selects a power level suitable for transmission/reception having a receive strength belonging to a pre-set threshold range among a plurality of different power levels, and informs the visible light communication transmitter about the selected power level.
Abstract:
A method for power control in a visible light communication and a receiving apparatus using the same are provided to enable a receiving device to get accurate information for power control and to perform appropriate reaction by judging a situation of the receiving device more accurately. A method for power control in a visible light communication comprises following steps of: performing communication between a transmitter and a receiver for visible light communication; measuring a bit error rate of a receiving signal in the visible light communication receiver(615); and requiring the power control to the transmitter of the visible communication according to the bit error rate of the measured receiving signal(620,655).
Abstract:
본 발명은 디지털 방송 시스템에서 디지털 방송을 수신하는 단말의 부드럽고 끊김없는 핸드오버를 지원하기 위한 방법 및 장치에 관한 것이다. 네트워크 노드에 의한 핸드오버 방법은, 서빙 셀에서 방송 서비스를 수신하는 단말로부터 신호품질 평가시간과 서비스 ID 및 셀 ID를 포함하는 핸드오버 제안 메시지를 수신하는 과정과, 상기 서비스 ID의 서비스를 제공하는 모든 후보 셀들의 신호 품질들을 평가하는 과정과, 상기 후보 셀들의 신호 품질들을 평가한 결과에 따라 상기 각 후보 셀들에 대한 핸드오버 가능 시간들을 나타내는 핸드오버 후보 파라미터를 계산하는 과정과, 상기 핸드오버 후보 파라미터를 상기 단말로 전송하는 과정을 포함한다. 단말은 상기 핸드오버 후보 파라미터의 상기 핸드오버 가능시간들에 따라 상기 후보 셀들 중 하나의 최적 셀을 선택하고, 상기 선택된 최적 셀로의 핸드오버를 수행한다. 이러한 본 발명은 핸드오버에 관련된 대부분의 처리 작업을 네트워크 노드에서 수행하도록 함으로써 단말이 단독으로 핸드오버할 때 해결할 수 없는 문제들을 극복할 수 있으며, 단말의 전력 소비를 크게 줄이는 효과가 있다. DVB, CBMS, 핸드오버, 연동 채널, 핸드오버 가능 시간, 핸드오버 간격
Abstract:
A method and an apparatus for supporting mobility in a DVB-H(Digital Video Broadcasting-Handheld) CBMS(Convergence of Broadcasting and Mobile Service) system are provided to transmit service mapping information of each TS(Transport Stream) and IP(Internet Protocol) platform, so that a user can continuously receive a broadcasting service even when the user gets out of a cell or network to which he/she belongs to enter a new network. A method for supporting mobility comprises the following steps of: setting up mapping information for broadcasting services of each of different TSs(Transport Streams) corresponding to a broadcasting service which a terminal is currently receiving(802); and transmitting the mapping information for the preset broadcasting service to the terminal(805).
Abstract:
A method and an apparatus for notifying the update of ESG(Electronic Service Guide) by using PSI/SI(Program Specific Information/Service Information) in a digital broadcasting system are provided to allow a terminal to receive accurate ESG information by informing information indicating whether the ESG is updated to a terminal by using the PSI/SI without delay although the update of the ESG information occurs without schedule. A PSI/SI processing unit(372) detects PSI/SI from a signal transmitted from a transmitter. An adjusting unit(382) judges whether the update of ESG occurs by referring to a descriptor included in the SI. If it is judged that the update of the ESG occurs, an ESG processing unit(380) detects ESG information from the signal transmitted from the transmitter.
Abstract:
본 발명은 부호 분할 다중 접속 기술을 사용하는 이동통신 시스템에서 배열 안테나를 이용한 다중 안테나 기술을 사용함에 있어서 각 안테나에서 송출되는 신호가 가질 수 위상 에러와 진폭 에러를 보정해 주기 위하여 시스템의 동작 이전 단계에서 보정을 수행하는 장치 및 방법과 시스템이 정상 동작 중인 상황에서 방향성 결합기를 사용하여 보정을 수행하는 장치 및 방법을 제안한다. 다중 안테나, 안테나 보정, 방향성 결합기