Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.