Patent application number | Description | Published |
20080304828 | OPTICAL COMMUNICATION SYSTEM USING WDMA AND CDMA - In a PON system, an OLT periodically transmits a channel resource information block specifying a carrier wavelength and a spreading code on a first downstream channel to which a spread-spectrum spreader having a first spreading code is applied; one of ONUs receives the channel resource information block with a spread-spectrum despreader having the first spreading code and transmits a connection request to the OLT, using the carrier wavelength and the spreading code specified by the channel resource information block; the OLT having received the connection request transmits a new channel resource information block specifying a carrier wavelength and a spreading code to be used on an upstream data channel to the requester ONU through the first channel; and the requester ONU transmits data, using the carrier wavelength and the spreading code specified by the new channel resource information block. | 12-11-2008 |
20090080888 | Optical line terminating apparatus and optical communication system - An optical access communication apparatus and an optical access communication system for the coexistence of two wideband PON systems without using an expensive optical device or module. A low-speed PON and a high-speed PON have a same upstream wavelength, and an OLT receives optical signals by a same optical receiver in the two systems, converts the optical signals into electric signals, amplifies the electric signals, branches the amplified electric signals, and processes the branched signals by clock and data recovery sections of bit rates corresponding to the two PON systems, thereby achieving an optical communication apparatus and an optical communication system for constructing a simple and low-cost triple-play service system of excellent transmission quality. | 03-26-2009 |
20090097861 | Passive optical network system and optical line terminating apparatus - A passive optical network (PON) system which enables plural types of ONUs having different signal transmission speeds to be connected to one OLT. An optical line terminating apparatus (OLT) connected to plural types of ONUs having different signal transmission speeds through an optical distribution network includes an optical transmitter-receiver connected to the optical distribution network, a transmission/reception line interface connected to a wide area network, a downstream frame processing section for converting a packet received by the transmission/reception line interface from the wide area network into a downstream frame containing identification information on a destination ONU in a header, and a downstream transmission controller for modulating the downstream frame at a speed corresponding to a signal transmission speed of the destination ONU and outputting the modulated frame to an electrical/optical converter connected to the optical transmitter-receiver. | 04-16-2009 |
20090162063 | NETWORK SYSTEM, OPTICAL NETWORK UNIT AND OPTICAL LINE TERMINAL - It is necessary to completely remove overlapping of signals between plural PONs in order to make the PONs coexist. Accordingly, it is required to share or intensively manage bandwidth use conditions over an optical fiber that serves as a common band between plural systems. Therefore, transmission clocks should be synchronized with high accuracy between plural systems. A reference clock is provided from an external device or a representative OLT to the entire systems to perform clock synchronization between plural systems, so that the overall systems are synchronized by synchronizing each OLT with the reference clock. A hierarchical management method is selected that manages ONUs under the control of each OLT by managing band use information arranged for each OLT with respect to an external device or a representative OLT for sharing of bandwidth use conditions between plural systems. | 06-25-2009 |
20090162064 | NETWORK SYSTEM AND OPTICAL LINE TERMINAL - It is necessary to completely remove overlapping of signals between plural PONs in order to make the PONs coexist. Accordingly, it is required to share or intensively manage bandwidth use conditions over an optical fiber that serves as a common band between plural systems. Therefore, transmission clocks should be synchronized with high accuracy between plural systems. A reference clock is provided from an external device or a representative OLT to the entire systems to perform clock synchronization between plural systems, so that the overall systems are synchronized by synchronizing each OLT with the reference clock. A hierarchical management method is selected that manages ONUs under the control of each OLT by managing band use information arranged for each OLT with respect to an external device or a representative OLT for sharing of bandwidth use conditions between plural systems. | 06-25-2009 |
20090162065 | NETWORK SYSTEM AND OPTICAL LINE TERMINAL - It is necessary to completely remove overlapping of signals between plural PONs in order to make the PONs coexist. Accordingly, it is required to share or intensively manage bandwidth use conditions over an optical fiber that serves as a common band between plural systems. Therefore, transmission clocks should be synchronized with high accuracy between plural systems. A reference clock is provided from an external device or a representative OLT to the entire systems to perform clock synchronization between plural systems, so that the overall systems are synchronized by synchronizing each OLT with the reference clock. A hierarchical management method is selected that manages ONUs under the control of each OLT by managing band use information arranged for each OLT with respect to an external device or a representative OLT for sharing of bandwidth use conditions between plural systems. | 06-25-2009 |
20090202242 | PASSIVE OPTICAL NETWORK SYSTEM, OPTICAL LINE TERMINATOR AND, COMMUNICATION METHOD OF PASSIVE OPTICAL NETWORK SYSTEM - A passive optical network system (PON) has a plurality of OLTs and ONUs with different transmission rates. OLTs with different transmission rates share information of priority frames and destinations, and determine timing for frame transmission to ONUs so that the signal from each of the OLTs does not collide when multiplied in a splitter. OLTs transmit the data to the ONU as a burst signal to prevent the signals with different rates from colliding. ONU acquires the information of the following burst frames. ONU receives only the signal addressed to the own ONU or with the transmission rate of own ONU, therefore errors in ONUs can be avoided. OLT receives only the signal with the transmission rate of own OLT from ONUs based on the transmission timing from the ONUs shared by the line terminators, errors in OLTs can be avoided. | 08-13-2009 |
20090245790 | PASSIVE OPTICAL NETWORK SYSTEM AND OPERATION METHOD OF THE SAME - In a passive optical network system, in order that by measuring a transmission distance and a transmission time between an OLT and an ONU in operation of the system, if the distance or the time is short, communication is conducted at a high transmission speed to increase a capacity of user; if the distance or the time is long, communication is conducted at a low transmission speed to increase the capacity of user communicating in a state in which a predetermined quality is secured, a main station includes a signal communication circuit to communicate with subsidiary stations at a first or second transmission speed and a controller to measure a transmission distance or a transmission time between the main station and each subsidiary station. Based on a result of the measurement, the controller selects a transmission speed for communication with the subsidiary station. | 10-01-2009 |
20090317082 | Passive Optical Network System, Optical Network Unit, and Optical Line Terminal - An optical line terminal (OLT), an optical network unit (ONT) and a passive optical network (PON) system are provided. A user of the ONU or a terminal connected with the ONU can accurately recognize the amount of a bandwidth allocated to the ONU without estimating the communication bandwidth. The OLT notifies each ONU of the amount of the bandwidth allocated to the ONU in response to a request transmitted from the ONU to the OLT. Each ONU receives bandwidth information from the OLT and displays thereon the bandwidth information or notifies the terminal connected with the ONU of the bandwidth information. | 12-24-2009 |
20100002591 | Communication System and Communication Apparatus - Communication time period measuring frames are simultaneously sent from an OAM adaptive device on a transmission side, to both a working path and a protection path. In an OAM adaptive device on a reception side, reception times of the frames having arrived from both the paths are checked so as to measure a time period difference between both the paths. The time period difference is fed back to a logic distance adjustment function of each PON section to determine required communication time periods of the PON sections respectively included in a working system and a protection system. Communication time periods of the working system and the protection system in a packet communication network are arbitrated in order to decrease a packet loss at line switching in a packet relaying network. | 01-07-2010 |
20100034534 | PASSIVE OPTICAL NETWORK SYSTEM, OPTICAL LINE TERMINATOR AND OPTICAL NETWORK UNIT - In a PON, at the time of ranging, an OLT (a master station) measures an optical level of a signal from at least an ONU (a slave station) capable of communicating at plural transmission speeds. The OLT determines the transmission speed applied to the ONU according to the measured level. Incidentally, the ONU may measure an optical level of a ranging request signal and determine the transmission speed. At a normal operation, when the OLT sends information of plural different transmission speeds to the ONU, a timing when a next frame reaches and transmission speed information are notified to the ONU. Based on the timing, the ONU receives only data of the transmission speed that can be handled. Besides, the OLT switches the transmission speed to receive data based on a grant designation transmitted from the plural ONUs to the OLT. | 02-11-2010 |
20100067901 | Passive optical network system and fault determination method - In a passive optical network system, a parent station includes a reception circuit that receives an optical signal from each of child stations using a threshold used to identify if the optical signal is 0 or 1; a bandwidth setting unit that determines a time at which each child station sends an optical signal; a storage unit that stores thresholds and intensities of optical signals received from the child stations; and a control unit that sets a threshold, stored corresponding to a sending time, in,the reception circuit to control a reception of an optical signal. The control unit has a function that compares an intensity of a signal received from each child station at an optical signal reception time with information stored in the storage unit to detect and determine a fault in the child station or in the optical fiber connected to the child station. | 03-18-2010 |
20100086304 | OPTICAL COMMUNICATION SYSTEM - A transmitting apparatus includes a plurality of code spreaders different in spreading code, a reception processing unit that selectively distributes transmission data to the plurality of code spreaders, a plurality of optical transmitters each of which that transmit a code-spread signal to an optical fiber as a CDMA optical signal of a carrier wavelength different from that of the other optical transmitters, and a signal multiplexing unit that selectively supplies outputs of the plurality of code spreaders to the plurality of optical transmitters, and a receiving apparatus includes an optical receiver that receives a wavelength-division-multiplexed CDMA optical signal from the optical fiber, and a plurality of despreaders connected to the optical receiver and different in spreading code, wherein each of the despreaders reproduces a CDMA signal corresponding to its spreading code from an output signal of the optical receiver. | 04-08-2010 |
20100158527 | OPTICAL COMMUNICATION SYSTEM USING WDMA AND CDMA - In a PON system, an OLT periodically transmits a channel resource information block specifying a carrier wavelength and a spreading code on a first downstream channel to which a spread-spectrum spreader having a first spreading code is applied; one of ONUs receives the channel resource information block with a spread-spectrum despreader having the first spreading code and transmits a connection request to the OLT, using the carrier wavelength and the spreading code specified by the channel resource information block; the OLT having received the connection request transmits a new channel resource information block specifying a carrier wavelength and a spreading code to be used on an upstream data channel to the requester ONU through the first channel; and the requester ONU transmits data, using the carrier wavelength and the spreading code specified by the new channel resource information block. | 06-24-2010 |
20100178051 | OPTICAL COMMUNICATION SYSTEM AND METHOD FOR OPERATING THE SAME - An optical communication system has a master station and a plurality of slave stations connected thereto via an optical fiber network, which is provided with an optical splitter and a relay unit which relays signals transmitted/received between the master station and the plurality of slave stations. The master station includes a first controller for performing ranging between the master station and the relay unit, and the relay unit includes a second controller for performing ranging between the relay unit and the plurality of slave stations. The master station determines, on the basis of the results of ranging performed by the first and second controllers as well as reports from the slave stations, timings for the slave stations to transmit signals to the master station, and receives signals multiplexed through the optical fiber network from the slave stations. | 07-15-2010 |
20100226244 | Network System - Provided is a multicast path management method for a connectionless communication. Also provided is a path protection function which is effective when a path has failed. A network is formed by a trunk and a branch path. The multicast path is managed by end-to-end and when a failure has occurred, an instruction is issued from the apex of the multicast tree to respective end-to-end paths so as to switch from the currently used channel to a backup path. Thus, upon failure, an individual path protection can be performed without affecting other parts of the tree to which the same multicast flow as the defective path is distributed or the distribution state of the multicast flow. | 09-09-2010 |
20120070147 | COMMUNICATION SYSTEM AND COMMUNICATION APPARATUS - Communication arrangements wherein each of ONUs of a first or second PON transmits data toward a connected first or second OLT after a wait time period designated by the connected first or second OLT; the first communication device of the first packet communication network sends a first frame for measuring communication time period, to the second communication device of the second packet communication network through the first PON, and sends a second frame for measuring communication time period, to the second communication device through the second PON; and the second communication device calculates a difference of communication time period between the received first and second frames, and instructs the first or second OLT of the first or second PON, for correcting a wait time period which is set to the one or plural ONUs connected to the first or second OLT, based on the difference between communication time periods. | 03-22-2012 |