Abstract:
본발명은고속 LED 디밍환경에서가변펄스위치변조를이용한가시광통신방법에관한것으로서, 더욱상세하게는 LED 송신부의밝기변화를단계적으로조절하고수신부의복조에이용되는상관마스크를생성할때 일부비트의평균밝기를이용하여 LED 송신부의밝기가고속으로변화하더라도전송및 수신성능에영향을주지않는가시광통신방법에관한것이다. 본발명에따른고속 LED 디밍환경에서가변펄스위치변조를이용한가시광통신방법은 (a) 송신제어부가가변펄스위치변조신호를송신하는 LED의목표밝기를입력받는단계; (b) 송신제어부가가변펄스위치변조신호의기설정된비트구간에상기 LED 의밝기를기설정된만큼변화시켜가변펄스위치변조신호를송신하는단계; 및 (c) 송신제어부가상기 LED 조명의밝기가상기목표밝기가될 때까지상기 (b)단계를반복하는단계; 를포함한다.
Abstract:
The present invention relates to a method for demodulating a variable pulse position modulation (VPPM) signal, which demodulates data from the VPPM signal. The method for demodulating the VPPM signal according to the present invention comprises the following steps: a sampling step of sampling a received VPPM signal; a measuring step of measuring the brightness of the sampled VPPM signal; generating mask 1 and mask 0 by using the measured brightness of the VPPM; a synchronizing step of synchronizing the generated mask 1 and mask 0 to the VPPM signal; and a demodulating step of demodulating data for the VPPM signal by using the synchronized mask 1 and mask 0.
Abstract:
본 발명은 가시광통신시스템에 관한 것으로, 본 발명은 입력된 전송데이터를 코딩하고 상기 코딩된 전송데이터를 복수 색상의 광신호로 변조하는 송신장치; 수신된 복수 색상의 광신호를 복조하고 상기 복조된 광신호를 디코딩하는 수신장치; 및 상기 송신장치와 상기 수신장치의 각 동작을 제어하는 제어장치;를 포함하는 것을 특징으로 한다. 이에 의해 본 발명은 전송데이터와 색상데이터를 기초로 변조된 광신호를 생성함으로써 가시광통신과 컬러조명을 동시에 수행할 수 있다.
Abstract:
PURPOSE: A visible light communication system using RGB(red, green, blue) LEDs is provided to obtain effectively modulated optical signals by inputting transmit data and color data to a controller for performing the visible light communication and color lighting at the same time. CONSTITUTION: A visible light communication system using RGB(red, green, blue) LEDs comprises the following: a transmitting device(100) coding inputted transmit data, producing a PWM signal corresponding to inputted color data, and operating plural LEDs having different colors for modulating the coded transmit data into optical signals in different colors using the PWM signal; and a receiving device(200) demodulating the optical signals, and decoding the demodulated optical signals.
Abstract:
A wavelength conversion apparatus in a TDM-PON system based on WDM(Wavelength Division Multiplexing) and an optical transmission apparatus and method using the same are provided to enable each subscriber group to have each instinct wavelength and transmit data to an OLT using an optical fiber, thereby improving the bandwidth efficiency of each subscriber and saving a transmission cost. An OLT(Optical Line Terminal) is positioned at a CO(Central Office). The OLT has an instinct wavelength and transceives data to each subscriber group. The OLT transmits data to plural subscribers using a transmitting terminal. ONUs(Optical Network Units) transmit the uplink data using the wavelength of 1310nm bandwidth used in an existing TDM-PON(Time Division Multiplexing-Passive Optical Network). An RN(Remote Node) routes ONU uplink signals to a wavelength conversion apparatus pre-assigned by subscriber group, converts the ONU uplink signals into signals in wavelength assigned in the wavelength conversion apparatus, and transmits the converted signals to the OLT.
Abstract:
The present invention provides a method for protection switching of a passive optical network (PON) and a PON system for the same, which normally uses a communication service using different wavelengths and which can enable a continuous communication service by protection switching to a normal optical line terminal (OLT) in the event of communication failure by using two optical line terminals (OLTs) in the PON. The method for protection switching of a PON according to the present invention comprises: a first step for allowing first and second OLTs to respectively check the communication status with a plurality of ONUs; a second step for allowing the first and second OLTs to respectively communicate with the ONUs using different wavelengths if the communication status with the ONUs are all normal; and a third step for allowing a normal OLT to communicate with the ONUs using the different wavelengths if communication failure occurs between one of the first and second OLTs and the ONUs. [Reference numerals] (110,120) First OLT