Nippon Telegraph and Telephone Corporation

Jun Terada

Naotaka Shibata

Kenji Miyamoto

Shigeru Kuwano

Hiroyuki Uzawa

Keita Takahashi

Rintaro Harada

Hirotaka Ujikawa

Noriyuki Ota

Hirofumi Yamamoto

Shin Kaneko

Yoichi Fukada

Hirotaka Nakamura

Tatsuya Shimada

Hideaki Kimura

Daisuke Hisano

Tatsuya Fukui

Hiroshi Ou

Tatsuya Shimizu

Takehiro Moriya

Yutaka Kamamoto

Takayuki Kobayashi

Kazuaki Honda

Takayoshi Tashiro

Yusuke Ohtomo

Keiji Kishine

Kazuyoshi Nishimura

Takeshi Sakamoto

Satoshi Shigematsu

Nobuyuki Tanaka

Junichi Kani

Hiroo Suzuki

Takuya Kanai

Jun-ichi Kani

Tomoaki Kawamura

Seiji Yoshida

Hiroko Nomura

Noriko Iiyama

Seiichi Sanpei

Shinsuke Ibi

Minoru Togashi

An optical signal processing apparatus includes a removal unit and a superimposition unit. The removal unit receives, from a first optical transmission path, an optical signal converted from an electrical signal, in which a first signal and a second signal having different frequencies from each other have been superimposed, and removes the second signal from the optical signal which has been input. The superimposition unit superimposes a third signal having a frequency different from a frequency of the first signal on the optical signal in which the second signal has been removed by the removal unit, and outputs the optical signal in which the third signal has been superimposed to a second optical transmission path.

Optical signal processing apparatus and optical signal processing method

A signal transfer control apparatus that performs a control operation to switch a plurality of communication paths constituted by a plurality of signal transfer apparatuses transferring a signal includes: a fixed delay information acquisition unit that acquires fixed delay information for each of the plurality of communication paths; a traffic information acquisition unit that acquires traffic information indicating a traffic volume or each of the plurality of communication paths; a probability density function estimation unit that estimates a probability density function of a traffic volume of each of the plurality of communication paths based on the traffic information; an occurrence probability estimation unit that estimates an occurrence probability of variable delay in each of the plurality of communication paths based on the probability density function of each of the plurality of communication paths; a communication path calculation unit that performs a calculation for specifying a communication path which is highly likely to satisfy a predetermined delay condition based on the occurrence probability of the variable delay in each of the plurality of communication paths and the fixed delay information for each of the plurality of communication paths; and a setting instruction unit that outputs a setting instruction for switching a transfer destination of a signal to at least any one of the signal transfer apparatuses so that the signal is transferred via the communication path specified by the calculation performed by the communication path calculation unit.

Performing a control operation to switch a plurality of communication paths

A wavelength multiplexing communication system includes a master station apparatus and a plurality of slave station apparatuses. The master station apparatus includes a wavelength multiplexing communication unit. The wavelength multiplexing communication unit performs wavelength multiplexing communication with the plurality of slave station apparatuses by using optical signals having the number of wavelengths equal to or less than the number of the plurality of slave station apparatuses. The slave station apparatus includes an optical communication unit. When the main signal communication is performed in the host slave station apparatus, the optical communication unit communicates with the master station apparatus by an optical signal having the same wavelength as a wavelength used by another slave station apparatus in which a main signal notification is not performed.

Wavelength multiplexing communication system and wavelength multiplexing communication method

There are included a control unit configured to, when detecting that no high priority traffic frame arrives for a frame interval threshold or longer in the period that allows high priority traffic frames to be transmitted, release the period that allows high priority traffic frames to be transmitted and allocate the released period to the period that allows low priority traffic frames to be transmitted, a frame arrival time information acquisition unit configured to obtain information of frame arrival times of high priority traffic frames, a frame interval calculation unit configured to calculate, in accordance with the information of frame arrival times obtained by the frame arrival time information acquisition unit, frame intervals between frames of the high priority traffic frames input in chronological order, a frame interval threshold calculation unit configured to calculate a new frame interval threshold in accordance with the frame intervals, and a frame interval threshold configuration unit configured to change the frame interval threshold to the new frame interval threshold.

Signal transfer device, signal transfer method, signal transfer control device, signal transfer control method and signal transfer program

An object is to provide a communication system, a communication apparatus, and a terminal apparatus capable of integrating communication paths of both of mobile access and fixed access while addition of a new function to a mobile network is reduced. In a communication systemaccording to the present invention, a communication path of one mobile bearer between a base station master station apparatusand a user gatewayincludes a split bearer configuration including a mobile access communication path being connected from the base station master station apparatusto the user gatewayvia a mobile access slave station apparatusand a non-mobile access communication path being connected from the base station master station apparatusto the user gatewayvia a non-mobile access slave station apparatus

Communication system, communication device, and terminal device

A relay device including: an information storage unit that stores conversion-target header information; a downlink signal dividing unit that divides a downlink signal received from the radio control device into a header and a payload; a signal replicating unit that makes the same number of copies of the payload of the downlink signal as the number of the plurality of destination radio devices; a downlink signal header information conversion unit that performs conversion on the header of the downlink signal for each destination radio device based on the header information stored in the information storage unit; and a signal addition assignment unit that adds the header converted by the downlink signal header information conversion unit to each of the payloads of the downlink signal replicated by the signal replicating unit, and transfers the payloads to the radio devices respectively corresponding thereto.

Relay device, relay method, and relay program

Time taken for resuming communication in a protection scheme using a backup path in an optical communication system including a master station device and a plurality of slave station devices is decreased. The plurality of slave station devices are connected in parallel to a looped path. A communication path between the master station device and each of the slave station device includes a normal path and a backup path. The master station device performs communication control processing for each of the slave station device based on RTT. A first slave station device is a slave station device with which communication through the normal path has become impossible. First backup path RTT of the first slave station device is calculated based on first normal path RTT of the first slave station device, first partial RTT between the master station device and the looped path, and loop propagation time necessary for one trip through the looped path. The communication control processing for the first slave station device is resumed based on the calculated first backup path RTT without measurement of the first backup path RTT when the first slave station device is sensed.

Optical communication system, master station, and optical communication method

Signal transfer devices that relay base stations of service providers that perform communication with radio terminals and an aggregation station that controls the base stations, and a route control device that controls signal distribution to user network interfaces (UNIs) and network network interfaces (NNIs) of each of the signal transfer devices, are included. The route control device includes an allocation information acquisition unit that acquires allocation information of frequency to each of the base stations; a band adjustment unit that adjusts an MBH band for each of the UNIs, on the basis of correspondence relation information representing a correspondence relation between the UNIs and the service providers, band information indicating a maximum MBH band of each of the UNIs, and the allocation information; and a distribution determination unit that determines signal distribution to each of the NNIs, on the basis of the MBH band adjusted by the band adjustment unit and configuration information representing a connection configuration of each of the signal transfer devices. The signal transfer device transmits a signal from each of the NNIs on the basis of the signal distribution to each of the NNIs determined by the distribution determination unit.

Signal transfer system, signal transfer method, and path control device

The present invention enables shortening the time required for resuming communication in a protection method that uses a backup path in an optical communication system that includes a master station device and multiple slave station devices. The slave station devices are connected to a loop path in parallel. The communication paths between the master station device and the slave station devices include a normal path and a backup path. The master station device executes communication control processing with respect to the slave station devices based on the RTTs. A first slave station device is a slave station device that cannot perform communication via the normal path. If the first slave station device is detected, the master station device calculates a first backup path for the first slave station device based on a first RTT between the master station device and the loop path, a loop RTT required for one full lap on the loop path, and the first normal path RTT for the first slave station device. The master station device then resumes communication control processing for the first slave station device based on the calculated first backup path RTT.

Optical communication system and master station

A relay device that relays between a plurality of radio devices that perform radio communication with terminals, and at least one radio control device that controls the radio devices, the relay device including: a replication necessity determination unit that determines whether or not to replicate a downlink signal received from the radio control device; a signal replicating unit that makes the same number of copies of a downlink signal as the number of destination radio devices only when the replication necessity determination unit determines that the downlink signal is to be replicated; and a downlink signal assignment unit that transfers a downlink signal that has been determined by the replication necessity determination unit as a signal that is not to be replicated, and downlink signals replicated by the signal replicating unit, to the radio devices respectively corresponding thereto.

A buffer unit including a plurality of buffers, a sorting unit configured to sort an input signal to any of the plurality of buffers based on header information, a rate calculation unit configured to calculate a rate at which the input signal is read from each of the plurality of buffers based on burst information of the input signal, an adjustment unit configured to adjust a rate at which the input signal is read from each of the plurality of buffers based on the rate calculated by the rate calculation unit, and a transfer unit configured to transfer the signal read from each of the plurality of buffers are provided.

Signal transfer device and signal transfer method

A signal forwarding system includes: a plurality of signal forwarding devices forming a plurality of communication routes between a slave station and a master station; and a route control device that determines a communication route, wherein the route control device includes at least: a communication route calculation unit that calculates a communication route in response to a route switching request; and a forward destination setting instruction unit that outputs forward destination setting information based on the communication route, the signal forwarding devices include at least: a forward destination setting instruction acquisition unit that acquires the forward destination setting information; a forward destination set unit that changes a forward destination based on the forward destination setting information; and a forward unit that outputs input traffic based on the forward destination, and any of the route control device and the signal forwarding devices includes: a traffic monitor unit; a non-signal period estimation unit that estimates a non-signal period in which the traffic does not flow; and a switching timing control unit that controls a switching timing to perform route switching in the non-signal period.

Signal transfer system, signal transfer device, route control device and signal transfer method

A path control device controls a plurality of paths for transmitting signals through a network including a plurality of signal transfer devices that transfer signals while switching a first transmission period during which high-priority traffic can be transmitted and a second transmission period during which low-priority traffic can be transmitted. The path control device includes: a calculation unit that calculates a plurality of paths through which signals are transferred, based on network configuration information indicating a configuration of the network; an estimation unit that estimates paths for low-priority traffic so as to increase the number of low-priority traffic flows to be transferred during a predetermined period through the plurality of paths calculated by the calculation unit, in a case in which the plurality of signal transfer devices detect an end of high priority traffic in the first transmission period, in accordance with statistical values in the second transmission period based on a transmission schedule made to change the first transmission period after the end of high-priority traffic to the second transmission period; and a determination unit that determines, for each of the plurality of signal transfer devices, output destination setting information such that the paths estimated by the estimation unit are set to an output destination of low-priority traffic.

Signal transfer system, path control device, and signal transfer method

A wavelength multiplexing communication system includes a master station apparatus and a plurality of slave station apparatuses. The master station apparatus includes a wavelength multiplexing communication unit that performs wavelength multiplexing communication with the plurality of slave station apparatuses by wavelengths the number of which is equal to or less than the number of the plurality of slave station apparatuses using an optical signal of a wavelength in a first wavelength group and an optical signal of a wavelength in a second wavelength group. The slave station apparatuses include an optical communication unit that performs communication of the main signal with the master station apparatus by an optical signal of a wavelength in the first wavelength group, which is different from a wavelength in the first wavelength group used by another slave station when the main signal communication is performed in the host slave station apparatus, and performs communication of a signal other than the main signal with the master station apparatus by an optical signal of a wavelength in the second wavelength group, which is a wavelength same as a wavelength used by another slave station apparatus when the main signal communication is not performed in the host slave station apparatus.

A path control method of controlling a communication path in a network including a plurality of wireless devices communicating with a terminal in a wireless manner and a plurality of wireless control devices communicating with any one of the plurality of wireless devices through a plurality of signal transfer devices includes searching for available communication paths and listing the available communication paths for individual combinations of a wireless device of the plurality of wireless devices and a wireless control device of the plurality of wireless control devices, and selecting a combination of communication paths in which a maximum value of the number of communications passing through the same output port of a signal transfer device of the plurality of signal transfer devices is minimized from among the listed available communication paths.

Growing community of inventors

Yokosuka, Japan

Jun Terada