Nippon Telegraph and Telephone Corporation

Katsuhiro Shimano

Ippei Shake

Mitsunori Fukutoku

Wataru Imajyuku

Satoru Okamoto

Eiji Oki

Takafumi Tanaka

Tetsuro Inui

Wataru Imajuku

Takahiro Yamaguchi

Atsushi Watanabe

Takayuki Nakachi

Yitu Wang

Yoshihiro Takikawa

Yasutaka Okazaki

Wataru Imaiyuku

The present disclosure has an object of proposing a method and a device for estimating the state of a transmission path or an optical transmitter capable of mechanically estimating a factor causing an error with a small amount of constellation data and a low computing amount. The present disclosure provides a device for estimating a state of optical communication, the device including: a data preprocessing unit that reduces the number of data using random sampling with respect to constellation data in which an amplitude and a phase of optical communication data are represented by a polar coordinate diagram and performs distribution calculation and a dimension reduction; a learning unit that learns a dictionary matrix in sparse coding using learning constellation data processed by the data preprocessing unit; and a recognition unit that calculates a sparse coefficient using recognition constellation data processed by the data preprocessing unit and the dictionary matrix learned by the learning unit and estimates a factor causing degradation of the optical communication using the calculated sparse coefficient.

Method, device and program for estimating optical communication status

A packet transfer method in a network apparatus that transfers packets is disclosed. In the packet transfer method, a sending side apparatus generates two copies of a send packet, provides a sequence number identifying the same sending sequence to each of the copied packets, provides an identifier corresponding to a send/receive pair to each of the copied packets to send the packets, and a receiving side apparatus receives each of the packets with two receiving units; recognizes the identifiers each corresponding to a send/receive pair; identifies packets having the same information and the sequence based on the sequence number when the identifiers are the same; selects one of the packets of the same sequence so as to send the packet downstream, and discards another packet, wherein, when only one of the packets of the same sequence arrives, the arriving packet is sent downstream.

Packet transmission method and packet transmission device

In a disclosed backup path bandwidth keeping method for keeping bandwidth of a backup path to which an active path is switched when the active path becomes unavailable in nodes of a communication network, each node is connected to the same destination, and the method includes a backup path bandwidth keeping phase, for M (M is a natural number equal to or less than L) channels in L (L is a natural number) channels kept as backup path bandwidth, for notifying a destination-side node existing in a destination side of the backup path of identification number information of the M channels to be kept and identification information indicating that a path for which the bandwidth is to be kept is a backup path.

Device and method for correcting a path trouble in a communication network

A path network and a path network operation method capable of dealing with an abrupt traffic variation by realizing fast path bandwidth increase are disclosed. A path network is operated by transmitting path signals from a transmitting node to a receiving node through the working paths and the protection paths, and converting a protection path into a working path temporarily in order to increase a bandwidth of the working paths when a bandwidth increase request occurs in the path network. The transmitting node and the receiving node can convert a protection path into a working path by using the automatic path conversion information contained in the path overhead attached to the path signals.

Path network and path network operation method using conversion of protection path into working path

Growing community of inventors

Yokohama, Japan

Katsuhiro Shimano