Oki Electric Industry Co., Ltd.

Masahiro Sarashina

Satoshi Furusawa

Akihiro Takahashi

Masayuki Kashima

Akiya Suzuki

Information about usage bandwidths of the ONUs and information about cover areas of the RRHs are acquired. A maximum cover area of each RRH is set. The remaining RRH included in the currently-set cover areas within the maximum cover area of each RRH is identified. The plurality of ONUs, a total usage bandwidth of which is smaller than or equal to an amount of traffic accommodatable by a single ONU, are identified as a sleep candidate ONU group. The ONU and the RRH to be switched to the sleep state are selected. If the maximum cover area of the RRH connected to one of the ONUs included in the sleep candidate ONU group includes a current cover area of the RRH connected to the remaining ONU, the remaining ONU and the RRH connected to them are selected as the ONU and the RRH to be switched to the sleep state.

Sleep control method and dynamic wavelength allocation control method

A band control system, a band control apparatus and a communication apparatus which realize low-latency band allocation assuming a plurality of radio control units are proposed. The band control system according to the present invention is a band allocation control system for optical communication which performs connection between a plurality of radio transmitting/receiving units connected to radio terminals and a plurality of radio control units corresponding to the plurality of radio transmitting/receiving units. Each of the radio control units includes a radio communication timing calculating unit configured to calculate a radio communication timing of each of the radio terminals in a connection network. The band control system includes a band allocation control unit configured to allocate an optical communication band according to the radio communication timing calculated by the radio communication timing calculating unit of each of the radio control units to each of a plurality of slave station apparatuses corresponding to the radio transmitting/receiving units, and a synchronization control unit configured to control synchronization among the plurality of radio control units.

Band control system, band control apparatus and communication apparatus

An optical signal generation section and a transmitter control section are provided. The optical signal generation section includes a light source, a temperature adjuster that adjusts a temperature of the light source, and a light amplifier that amplifies light generated by the light source and generates burst signals. The transmitter control section includes a temperature change suppresser that sends a temperature suppression signal to the temperature adjuster, the temperature suppression signal reporting a temperature suppression amount that is to suppress a temperature change of the light source caused by burst signal generation at the light amplifier. The temperature adjuster receives the temperature suppression signal at least a duration that the temperature adjuster requires for temperature adjustment before a timing at which the light amplifier is to generate a burst signal.

Optical transmitter, subscriber side device, and light source temperature change suppression method

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.

DWA control in an OLT with decrease in margin of bandwidth utilization caused by bandwidth reallocation minimized

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.

Exchange device

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.

Optical network unit registration method

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.

Method for registering optical network unit in telecommunications network and optical network unit therefor

In a transmission control apparatus, connected communication devices are detected to find round trip time of transmission to each of the detected communication devices, and the order of each communication device is determined on the basis of the round trip time of transmission to that communication device depending upon the distance thereto. On the basis of the round trip times of transmission to, and the orders of, the communication devices, transmission wait times are determined for delaying transmission of control signals from the communication devices to notify the communication devices of the transmission wait times. When starting communication with the communication devices, timer start signals prompting the communication devices to start counting the transmission wait time are transmitted to the communication devices.

Transmission control apparatus improved in transmission efficiency of downstream data

In an optical communication system that communicates between an optical line terminal (OLT) and a plurality of optical network units (ONU), an ONU can decide an operation time period of communicating with the OLT and an idle time period of reduced or suspended communication with the OLT by using a timer. The OLT can decide a software renewal time period based on the operation time period and the idle time period. Accordingly, the ONU can supply electrical power to its own communication circuit during the operation time period or the software renewal time period, or cut off or reduce the electrical power if a present time does not occur in either the operation time period or the software renewal time period.

Power supply control method, an optical network unit, an optical line terminal and a communication system

The present invention provides a station-side terminal device including a control signals reading/generating section that receives a requested bandwidth which the subscriber-side terminal devices require for the communication, from each of the subscriber-side terminal devices, and an uplink band allocating section including a first calculation section that allocates a usable communication bandwidth to each of the subscriber-side terminal devices based on a ratio of a service level parameter predetermined for each of the subscriber-side terminal devices, and a second calculation section that obtains an updated usable communication bandwidth updated by subtracting a sum of the allocated bandwidths from the usable communication bandwidth, and obtains an updated requested bandwidth updated by subtracting the allocated bandwidth from the requested bandwidth, to allocate the updated usable communication bandwidth to each of the subscriber-side terminal devices based on a ratio of the updated requested bandwidth.

Dynamic communication bandwidth allocation method, computer-readable medium storing dynamic communication bandwidth allocation program, semiconductor chip, and PON system

A bandwidth allocating control apparatus for use in an optical communication base station has its reception bandwidth divided into a bandwidth for short distance and a bandwidth for long distance. A residual bandwidth calculator calculates a residual bandwidth remaining unallocated in the bandwidth for short distance after having allocated the reception bandwidth to short-distance subscriber terminal units. A middle-distance subscriber terminal classifier uses a middle-distance boundary calculation model representing the relationship between the residual bandwidth and a communication distance from the base station to the subscriber terminal units to further classify long-distance subscriber terminal units into a middle-distance subscriber terminal unit and a long-distance subscriber terminal unit. A middle-distance bandwidth allocator further allocates the residual bandwidth to the middle-distance subscriber terminal unit in addition to a predetermined bandwidth allocated thereto.

Dynamic bandwidth allocating control apparatus with bandwidth usability improved

A subscriber terminal connected to a central-office unit in an optical communication network includes a variable optical attenuator for attenuating an optical signal received from the central-office unit; an optical-electric converter for converting the optical signal received via the attenuator to a corresponding electric signal; a clock extractor for extracting a clock from the electric signal and producing a clock extraction information signal representing whether or not the clock is extracted stably; and a terminal controller. The controller includes a clock extraction decider for determining whether or not the extractor stably extracts the clock on the basis of the information signal, a receiving level adjuster for setting an attenuation value to a value between a minimum and a maximum value, and an attenuation controller for setting the attenuation amount for the attenuator to the set attenuation value.

Subscriber terminal of adjusting intensity of optical signal by controlling attenuation, and a method thereof

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.

Synchronized code division multiplexing communication method and synchronized code division multiplexing 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.

Code division multiplex communication 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.

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Tokyo, Japan

Masahiro Sarashina