Patent application number | Description | Published |
20090208213 | Code division multiplex signal receiving apparatus and code division multiplex transmitting and receiving system - In a code division multiplex transmitting and receiving system, the transmitting apparatus inserts a clock signal in the code division multiplex signal. The clock signal has a frequency equal to a null frequency in the frequency spectrum of the code division multiplex signal. The receiving apparatus extracts this frequency component from the received signal and recovers the clock signal, using an ordinary clock recovery device of the type designed to recover a clock signal from a bi-level signal. The recovered clock signal is used as a synchronizing signal in the processing of the received signal. | 08-20-2009 |
20090220232 | Code division multiplex communication system - A code division multiplex (CDM) communication system transmits frames including a preamble and its end bit pattern followed by a CDM signal and its end bit pattern in respective time slots. A clock recovery device at the receiving end recovers a clock signal from the preamble during the preamble time slot and continues to output the clock signal in free run mode during the CDM signal time slot. The clock signal is used to gate the output of a decoder that decodes the received signal, so that the decoded CDM signal is output as a received data signal. The preamble is a bi-level signal, so an ordinary clock recovery device can be used. | 09-03-2009 |
20090232499 | Passive optical network communication method and system - A passive optical network communication system transmits an optical time-division multiplexed signal from a central office through a passive optical coupler to a number of subscribers, and transmits optical encoded signals from the subscribers through the passive optical coupler to the central office. Optical encoded signals from different subscribers are separated by a decoding process performed at the central office. All operations can be synchronized with a clock signal which is generated at the central office and recovered from the optical time-division multiplexed signal by the subscribers' equipment. The communication range can be extended inexpensively by using a single high-power light source at the central office while using relatively low-power light sources at the subscribers' equipment. | 09-17-2009 |
20100080559 | Synchronized code division multiplexing communication method and synchronized code division multiplexing communication system - A synchronized CDM communication system performs 1-to-N communication by CDM between a central office and first to N-th optical network units (ONU). The synchronized CDM communication system adds structural elements for realizing a connection state acquisition section to a conventional synchronized CDM communication system. A central office includes a presence check section, a ranging processing section and the connection state acquisition section. The presence check section checks the ONUs that are connected with the central office and the ONUs that are not connected. The ranging processing section performs transmission timing adjustments for the ONUs that are connected. The connection state acquisition section verifies whether all of ONUs are connected with the central office, and performs a discovery of a ONU, among the ONUs that were not connected at the time of the check, that has resumed participation in communication since the check ended. | 04-01-2010 |
20130230315 | EXCHANGE DEVICE - The exchange device groups PON branches into PON branch groups based on the amount of communication data traffic that has arrived via a communication network with a plurality of optical network units (ONUs) respectively belonging to one of a plurality of PON branches as a transmission destination, multiplexes the communication data for each PON group, and transmits the multiplexed data. The exchange device has an unit configured to transmit each piece of communication data from the ONUs to one output port selected from among a plurality of output ports based on the transmission wavelength of the communication data. The exchange device groups a plurality of PON branches into PON branch groups based on the required bandwidth of each of the ONUs, and designates the transmission wavelength for each of the ONUs so that each piece of the communication data from one PON branch group is transmitted to one port. | 09-05-2013 |
20130259482 | OPTICAL NETWORK UNIT REGISTRATION METHOD - In a network that includes one or a plurality of optical line terminals, a plurality of branches, and an optical routing unit, the optical network unit registration method includes a first process in which the optical line terminals transmit a discovery gate to the optical network units, and a second process in which, in response to the discovery gate, an unregistered optical network unit transmits a register request to a separate optical line terminal from the terminal that transmitted the discovery gate. A discovery window is provided in the optical line terminal that receives the register request. This optical line terminal receives the register request in the discovery window. | 10-03-2013 |
20140270775 | METHOD FOR REGISTERING OPTICAL NETWORK UNIT IN TELECOMMUNICATIONS NETWORK AND OPTICAL NETWORK UNIT THEREFOR - In a telecommunications network including an optical line terminal (OLT) having optical subscriber units (OSUs) and an optical network unit (ONU) connected to the OLT, bandwidth allocation signals are periodically transmitted at a first period from the respective OSUs to the ONU, and an acknowledgement request signal is transmitted from at least one of the OSUs to the ONU at a second period having a value corresponding to the first period multiplied by a constant. If an ONU is registered in none of the OSUs, the first period is determined from reception intervals of the assignment signals, and a second period is calculated from the first period. Transmissive wavelength of a variable-wavelength (VW) filter in the ONU is periodically changed at a third period longer than the second period. In the OSU having transmitted the request signal, the unregistered ONU having received the request signal is registered. | 09-18-2014 |
20150280851 | DWA CONTROL IN AN OLT WITH DECREASE IN MARGIN OF BANDWIDTH UTILIZATION CAUSED BY BANDWIDTH REALLOCATION MINIMIZED - In a TDM/WDM-PON using cyclic sleep, a controller in an OLT calculates the total bandwidth in use for each OSU, and compares the total bandwidth with a threshold. If the calculated bandwidth exceeds the threshold, the controller determines the number of ONUs staying in sleep mode among the ONUs managed by the assignor OSU. If such an ONU exists, that ONU is selected as an ONU whose management is to be changed. From the total bandwidth in use of an assignor OSU from which the management is to be changed, a bandwidth allocated to the ONU which is in sleep mode is subtracted to thereby obtain a bandwidth, which will be compared with the threshold. If the calculated bandwidth exceeds the threshold, from among active ONUs managed by the assignor OSU an ONU whose management is to be changed is selected. | 10-01-2015 |