Patent application number | Description | Published |
20100127831 | ACTIVE RFID APPARATUS FOR IMPROVING PN CODE GNENRATION - An active radio frequency identification (RFID) apparatus having an additional transmitter in addition to a single transmitter is provided. The active RFID apparatus includes a first transmitter including a first pseudo noise (PN) code generator to generate a direct sequence spread spectrum (DSSS) introduced by ISO/IEC (International Organization for Standardization/International Electrotechnical Commission) 24730-2 or ISO/IEC 18185-5 type B; and a second transmitter including a second PN code generator to perform an AND operation on an initial value and a fed back value and shift the resultant value of the AND operation, to perform an XOR operation on particular bits from among the shifted bits and to perform an XOR operation again on the shifted bits and the resulting value of the XOR operation to finally generate a PN code. Accordingly, where an additional PN code is added besides an existing PN code, a PN code having excellent auto correlation characteristics allowing discrimination of the PN code itself and cross-correlation characteristics providing a code discrimination ability with respect to another code can be generated. | 05-27-2010 |
20100127934 | POSITIONING SYSTEM, COMMUNICATION SIGNAL RECEIVER FOR POSITIONING SYSTEM, AND POSITION CALCULATION METHOD - A positioning system is provided which is capable of calculating the position of a target object even though it does not detect some synchronous signal necessary for position calculation. A communication signal receiver which provides information used in the position calculation is also provided. The positioning system includes a plurality of communication signal receivers each to detect a communication signal from a target object to be tracked and synchronous signals repeatedly transmitted for timing synchronization, and to acquire a receiving time interval between the synchronous signals, a receiving time interval between the synchronization signal and the communication signal, and synchronization signal identification information; and a position calculator to calculate a position of the target object by calculating a receiving time error of the communication signal from the receiving time interval between the synchronous signals, the receiving time interval between the synchronization signal and the communication signal, and the synchronization signal identification information. | 05-27-2010 |
20100158165 | PARALLEL AUTOMATIC FREQUENCY OFFSET ESTIMATION METHOD AND APPARATUS - Disclosed is a wireless signal receiving apparatus, and more particularly, disclosed is a parallel automatic frequency offset estimation apparatus and method for tracking a frequency offset in an early stage by calculating, in parallel, frequency offsets of a received signal. The parallel automatic frequency offset estimation apparatus includes a receiving unit to receive a data frame; and a frequency offset estimation unit to calculate, in parallel, frequency and phase deviations at different bit intervals within a particular section of the received data frame, to add together the frequency and phase deviations to obtain a first sum of the frequency and phase deviations, and to add the first sum to a frequency phase deviation calculated for each bit after the particular section in the received data frame to obtain a second sum of the frequency and phase deviations. Accordingly, transmission frequency tracking can be performed at higher speed, compared to the conventional systems in which frequency offset acquisition is carried out in stages. Also, accurate tracking of a transmission frequency is possible in an initial frame. | 06-24-2010 |
20130163629 | USER-SELECTABLE LASER AND OPTICAL TRANSMITTER HAVING THE SAME - Provided are a user-selectable laser and an optical transmitter including the same. The user-selectable laser is an external cavity laser including a semiconductor laser diode for outputting an optical signal, and a wavelength selection filter. The user-selectable laser may allow a user to select a wavelength selection filter which is optically coupled with the semiconductor laser diode and selectively causes oscillation at the wavelength of an optical signal output from the semiconductor laser diode. | 06-27-2013 |
20130294768 | OPTICAL LAYER MONITORING APPARATUS AND METHOD THEREOF - An optical layer monitoring apparatus and method thereof are provided. According to an embodiment of the present invention, an optical layer monitoring apparatus including an optical time domain reflectometer (OTDR) function so as to monitor an optical path of a passive optical network (PON), and a method for improving accuracy of measured monitoring results using the optical layer monitoring apparatus are provided. Therefore, it is possible to enable a user to continuously detect distortion or attenuation along the optical path, and to quickly recover from the distortion or attenuation along the optical path when distortion or attenuation is detected. | 11-07-2013 |
20130302029 | WAVELENGTH TUNING TIME MEASUREMENT APPARATUS AND METHOD FOR MULTI-WAVELENGTH PASSIVE OPTICAL NETWORK - A wavelength tuning time measurement apparatus and method for a multi-wavelength passive optical network (MW PON) are provided. The wavelength tuning time measurement apparatus for measuring a wavelength tuning time of a wavelength-variable light source included in the MW PON system includes an optical filter configured to pass only light of a certain wavelength bandwidth and a photo detector configured to sense light passing through the optical filter. The wavelength tuning time is a time taken from a time when a wavelength change signal is transferred to the wavelength-variable light source, to a time when light starts to be successively sensed by the photo detector. | 11-14-2013 |
20140104599 | METHOD OF IMPROVING PERFORMANCE OF OPTICAL TIME DOMAIN REFLECTOMETER (OTDR) - A method of improving the performance of an optical time domain reflectometer (OTDR) is provided. The method according to an embodiment of the present invention can increase accuracy of a distance of the OTDR through an initial calibration method with respect to the refractive index of an optical fiber, and can accurately detect a fault position and accurately analyze a fault cause through a real-time calibration method with respect to the refractive index of the optical fiber when faults and performance degradation occur. | 04-17-2014 |
20140199074 | ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS-PASSIVE OPTICAL NETWORK COMPRISING OPTICAL NETWORK UNIT AND OPTICAL LINE TERMINAL - An orthogonal frequency division multiple access-passive optical network including a plurality of optical network units each configured to generate orthogonal frequency division multiplexed signals, which are allocated thereto, based on a central frequency for frequency division multiplexing that is allocated in advance, and to use the generated signals in upstream transmission. | 07-17-2014 |
20140205279 | DEVICE FOR MONITORING OPTICAL LINK FAULT AND METHOD THEREOF - There are provided a device for monitoring an optical link fault and a method thereof. According to an embodiment of the invention, the device for monitoring an optical link fault and the method thereof apply an optical link fault monitoring signal to an optical link and precisely identify a type of the fault using waveforms of a reflected signal returned from the optical link or a wavelength dependence of reflected signal intensity. | 07-24-2014 |
20140219659 | METHOD OF ALLOCATING UPSTREAM BANDWIDTH RESOURCE AND METHOD OF TRANSMITTING UPSTREAM DATA IN ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS-OPEN OPTICAL SUBSCRIBER NETWORK - There are provided a method of allocating upstream bandwidth resources and a method of transmitting upstream data in an orthogonal frequency division multiple access-open optical subscriber network. The method of allocating an upstream bandwidth resource according to an embodiment of the invention includes receiving queue status information from each optical network unit (ONU), and allocating an upstream bandwidth by providing to each ONU a 2-D upstream bandwidth map on a subcarrier-time resource through a frame synchronized at constant cycles, based on the queue status information received from each ONU. | 08-07-2014 |
20140219661 | METHOD OF SELECTING WAVELENGTH OF OPTICAL NETWORK UNIT IN PASSIVE OPTICAL NETWORK - Provided is a method of selecting a wavelength of an optical network unit including selecting a pre-loaded default wavelength as an available wavelength candidate or the wavelength that has been changed when a preset wavelength changing condition is satisfied as the available wavelength candidate, acquiring frame synchronization for a downstream signal having the same wavelength as the selected available wavelength candidate, and transmitting a registration request message to an optical line terminal (OLT) from which the downstream signal has been transmitted when the frame synchronization is acquired, assigning the available wavelength candidate to an available wavelength used for communication with the OLT and registering the terminal in the OLT when a registration allowance message is received from the OLT. | 08-07-2014 |