Nippon Telegraph and Telephone Corporation

Jun-ichi Kani

Katsumi Iwatsuki

Mitsuhiro Teshima

Naotaka Shibata

Hiroo Suzuki

Noboru Takachio

Koji Akimoto

Ryogo Kubo

Akihiro Otaka

Masamichi Fujiwara

Shingo Kawai

Shigeki Aisawa

Tadashi Sakamoto

Masahiko Jinno

Seiji Norimatsu

Takahiro Suzuki

Takashi Yamada

Jun Terada

Manabu Yoshino

Shigeru Kuwano

Katsuhiro Araya

Seiji Yoshida

Sang-Yuep Kim

Noriko Iiyama

Masaki Fukui

Noriko Ilyama

Takuya Nakamura

A service start method is a service start method executed by a communication system, and the service start method includes: a step of acquiring identification information or authentication information of a device, a customer, or a service; a step of making authentication of the device, the customer, or the service to succeed when the identification information or the authentication information has been acquired together with information that is associated with the customer or a customer's location in advance, or when the identification information or the authentication information has been acquired from a terminal or a line that is associated with the customer in advance; and a step of starting provision of the service for the device for which the authentication has succeeded.

Service start method and communication system

An optical line terminal (OLT) () includes an interface (I/F) board () configured to communicate with an external apparatus, a graphics processing unit (GPU) () configured to perform a first process, and a central processing unit (CPU) () configured to control the I/F board () and the GPU (). The CPU () includes a data processing execution unit configured to execute a second process, an external transfer control unit configured to perform a control process of transferring data received from the external apparatus from the I/F board () to the CPU () or the GPU () and a control process for transferring data to be transmitted to the external apparatus from the CPU () or the GPU () to the I/F board (), a data processing control unit configured to perform control for executing the first process of the GPU () and the second process of the CPU () on the data received from the external apparatus or the data to be transmitted to the external apparatus; and a processing result copy unit configured to perform control for outputting a processing result of the first process to the CPU () and designating the processing result of the first process as a processing target of the second process and control for outputting a processing result of the second process to the GPU () and designating the processing result of the second process as a processing target of the first process.

Data processing system, central arithmetic processing apparatus, and data processing method

Since a sampling frequency of RRU is always constant, A/D conversion may be performed with a sampling frequency higher than necessary with respect to a frequency band width of a radio signal. A sampling frequency change function, and the sampling frequency is reduced in a range where a aliasing component does not deteriorate signal quality of a desired signal component when the sampling frequency is decreased, based on radio band allocation information, or signal transmission between BBU and RRU is stopped in a no signal section, whereby a band required for digital RoF transmission between the BBU and the RRU is reduced.

Distributed radio communication base station system, base band unit, remote radio unit, and method for operating distributed radio communication base station system

A method of operating an optical-wireless access system, wherein an ONU obtains information on dynamic scheduling control of the optical-wireless access system, information on discontinuous reception control of the optical-wireless access system, or both of them, and such information is used in the ONU or transferred to an OLT and used as parameters of scheduling in the PON and sleep control.

Optical-wireless access system

An OLT of a PON obtains information on discontinuous reception of a UE from a BBU of LTE, and adjusts a sleep start timing and a sleep cycle of an ONU so that a recovery waiting time in the OLT with respect to downlink data transmitted from the BBU to the UE can be minimized.

Optical wireless access system

An optical line terminal which includes an observing unit that observes information of any one or all of an arrival interval of frames, an instantaneous bandwidth under use of a flow, a queue length of a queue temporarily storing the frames, and a traffic type, and a stop determining unit that dynamically determines a sleep time to be a period in which a sleep state where partial functions of the ONU are stopped is maintained, on the basis of the information obtained by the observing unit. The ONU is entered into a sleep state, immediately after communication ends, after a predetermined waiting time passes from when the communication ends, or after a waiting time determined on the basis of the information passes from when the communication ends.

Optical line terminal and optical network unit

The present invention provides an optical wavelength-division multiple access system and a corresponding optical network unit. A wavelength band Da (wavelengths &#x3bb;dto &#x3bb;dn) for downlink optical signals corresponding to the n ONUs, a wavelength band Ua (wavelengths &#x3bb;uto &#x3bb;un) for uplink optical signals corresponding to the n ONUs, a wavelength band Db (wavelengths &#x3bb;dn+1 to &#x3bb;dn+m) for downlink optical signals corresponding to the m ONUs, and a wavelength band Ub (wavelengths &#x3bb;un+1 to &#x3bb;un+m) for uplink optical signals corresponding to the m ONUs are set different from one another, the wavelength bands Ua and Ub are set adjacent to each other, and the wavelength bands Ua and Da or the wavelength bands Ub and Db are set adjacent to each other. Each of the ONUs has downlink optical signal receiving unit for receiving a downlink optical signal of one of the wavelengths &#x3bb;dto &#x3bb;dn+m in the wavelength bands Da and Db which wavelength is assigned to the ONU, and uplink optical signal receiving unit for receiving an uplink optical signal of one of the wavelengths &#x3bb;uto &#x3bb;un+m in the wavelength bands Ua and Ub which wavelength is assigned to the ONU or an uplink optical signal within a broad band including the wavelength bands Ua and Ub.

Optical wavelength-division multiple access system and optical network unit

A first optical fiber transmission path is used to transmit continuous-wave light for upstream signal light from the center node to each of the remote nodes, while a second optical fiber transmission path is used to transmit downstream signal light from the center node to each remote node and to transmit upstream signal light (obtained by modulating continuous-wave light) from each remote node to the center node. In this network, specific wavelength bandwidths are allocated to each remote node for the continuous-wave lights (for upstream signal lights) and the downstream signal lights, and the wavelength bandwidths for the continuous-wave lights (for upstream signal lights) and the downstream signal lights are alternately set.

Ring network using multi-wavelength generator

In an optical wavelength division multiplexed access system, a center unit (OSU) and n optical network units (ONUs) are connected together via a wavelength splitter and optical fiber transmission lines, and downstream optical signals from the OSU to the ONUs and upstream optical signals from the ONUs to the OSU are transmitted in both directions, the wavelength spacing &#x394;&#x3bb;d (optical frequency spacing &#x394;fd) of the downstream optical signals is set to twice or more the wavelength spacing &#x394;&#x3bb;u (optical frequency spacing &#x394;fu) of the upstream optical signals, each ONU transmits an upstream optical signal whose optical spectral width is twice or more &#x394;&#x3bb;u (&#x394;fu), and the wavelength splitter spectrum slices the upstream signals transmitted from the ONUs into wavelengths (optical frequencies) whose optical spectral widths are mutually different within &#x394;&#x3bb;u (&#x394;fu), and wavelength-division multiplexes them and transmits to the OSU.

Optical network unit, wavelength splitter, and optical wavelength-division multiplexing access system

Cost-reduction in an optical communication unit is achieved by using spectrum-sliced modulated broadband light for transmitting upstream signals, instead of using laser light. An optical communication system includes at least one pair of optical communication units that each has a bi-directional network interface in which physical bit rates of transmission signals and reception signals are identical, an optical transmitter, and an optical receiver, and that performs bi-directional transmissions via at least one optical fiber. One optical communication unit includes a physical bit rate down-converter that lowers the physical bit rate of transmission signals from the bi-directional network interface and outputs to the optical transmitter, and the other optical communication unit includes a physical bit rate up-converter that raises the physical bit rate of signals received by the optical receiver and outputs to the bi-directional network interface. These optical communication units are also applicable to wavelength-division multiplexing systems.

Optical communication system, optical communication unit, and optical transceiving package

Multi-wavelength light having a frequency band equal to or greater than the FSR of an AWG is demultiplexed into individual wavelength channels, and power level deviations between wavelength channels are suppressed. An optical demultiplexer includes a wavelength-group demultiplexer that demultiplexes multi-wavelength light into wavelength groups formed from wavelength channels, and channel demultiplexers that demultiplex each wavelength group into wavelength channels light. An optical multiplexer includes channel multiplexers that multiplex modulated signal light of each wavelength channel for each wavelength group, and a wavelength-group multiplexer that multiplexes, for each wavelength group, WDM signal light output from the channel multiplexers. The FSR of the wavelength-group multiplexer/demultiplexer is set to be equal to or greater than the frequency band of the multi-wavelength light. The channel multiplexer/demultiplexer is an AWG in which the FSR is approximately the full width at half maximum of the transmission characteristics of each port of the wavelength-group multiplexer/demultiplexer.

Multi-wavelength optical modulation circuit and wavelength-division multiplexed optical signal transmitter

In a wavelength division multiplexed optical transmission system wherein the zero dispersion wavelength of the optical fiber transmission pathis in the 1550 nm region, among multiplexed optical signals, the wavelengths of either of at least two optical signals are allocated between 1450 nm and 1530 nm, or between 1570 nm and 1650 nm.

Wavelength division multiplex optical transmission system

A multilevel light-intensity modulating circuit for suppressing the amplitude distortion regarding intermediate levels, caused by the conversion from a multilevel electric signal to a multilevel modulated optical signal. The circuit comprises a section for distributing an input optical carrier into n-channel optical carriers; n light-intensity modulators for modulating intensities of the optical carriers by using input two-level electric signals; a control section for producing a phase difference between the n-channel two-level modulated optical signals; a control section for assigning a different light intensity to each of the n-channel two-level modulated optical signals; and a section for combining the n-channel two-level modulated optical signals obtained via the control sections, and outputting a 2 -level modulated optical signal. The phase difference and the different light intensity are defined in advance so as to produce the 2 -level modulated optical signal.

Growing community of inventors

Yokohama, Japan

Jun-ichi Kani