Hitachi, Ltd.

Nippon Telegraph and Telephone Corporation

Other

Masahiro Takatori

Yoshihiro Ashi

Yukio Nakano

Hiroyuki Nakano

Satoshi Aoki

Shinya Sasaki

Shin Nishimura

Naohiro Sakakida

Hironari Matsuda

Keiji Tomooka

Toru Kazawa

Ryoji Takeyari

Akihiko Takase

Masaru Murakami

Tadayuki Kanno

Koji Wakayama

Masashi Yano

Kazuho Miki

Tetsuro Yoshimoto

Masao Kunimoto

Yukio Hayashi

Takashi Mori

Hiromi Ueda

Hiroyuki Fujita

Yasuyuki Fukashiro

Masaki Ohira

Hirohisa Sano

Shigeki Kitajima

Tatsuo Kanetake

Hitomi Nakamura

Shoichi Hanatani

Hideaki Tsushima

Naruhito Nakahara

Nodoka Mimura

Yasushi Takahashi

Tohru Kazawa

Takahiko Kozaki

Noboru Endo

Yoshitaka Takasaki

Yuichi Yamaguchi

Junichirou Yanagi

Takehiro Morishige

Yoshihiro Shimizu

Ryuji Ishii

Norihisa Matsumoto

Naoya Kobayashi

Yasushi Sawada

Youichi Igarashi

Sunao Kakizaki

Masahiro Koya

Takaaki Toyama

Toshiyuki Atsumi

Toru Okamoto

Yuichiro Katsu

Kentarou Watanabe

Tomohiro Mori

Shinichi Kuwano

Yozo Oguri

Kaori Nakayama

Yoshiaki Takemura

Yoshihiro Yano

Kyoji Takeyari

Hitoshi Yajima

Keiichi Ishida

Kenji Tomooka

Ryoji Tateyari

After a first base station connects to a first mobile terminal, a first GW (gateway) receives a request for connection between the first mobile terminal and a second GW and identifiers of the second GW and the first mobile terminal and transmits identifiers of the first mobile terminal and the first GW to the second GW. The second GW transmits an MPLS allocation flag to the first GW. The first GW transmits an MPLS allocation signal including an identifier of the first mobile terminal to the second GW via a second NW (network) apparatus. The first base station receives an identifier of the first GW and the MPLS allocation flag from the first GW via a management server and transmits the MPLS allocation signal including the identifier of the first mobile terminal to the first GW via a first NW apparatus.

Network system including radio network using MPLS

Disclosed is a mobile communication system preventing the transmission of acknowledgements at a burst leading to a decrease in throughput caused by detecting the retransmission and the congestion of packets at the protocol of a transport layer. In a mobile communication system including a mobile terminal and gateway equipment for relaying a packet between a communication partner and the mobile terminal, if the gateway equipment receives the acknowledgement from the mobile terminal, the gateway equipment waits the transmission of the received acknowledgement to the communication partner until the estimated transmission time passes from the time at which the gateway equipment receives the previous acknowledgement from the mobile terminal.

Mobile communication system and communication method

It is provided a mobile communication system comprising base stations, call control servers and access gateways. The call control servers cause a mobile terminal accommodated in one of the control server to transmit the location registration request so that the mobile terminal accommodates in another control server according to a processing amount of control signals. The base station selects a second call control server into which the one of the mobile terminals is to be newly accommodated. The one of the call control server switches to a power-saving state after the mobile terminal is accommodated into the another call control server.

Mobile communication system for low power consumption, call control server and access gateway

A base station accommodation server can appropriately set a location registration area according to an installation location of a femto base station. The base station accommodation server is coupled to a location management server accommodating at least one first base station coupled to a first communication network, and accommodates at least one second base station connected to a second communication network. The base station is configured to determine a location management group identifier of the second base station based on a location management group identifier of the first base station that is present at a location from which the second base station can receive the location management group identifier broadcast by the first base station.

Wireless communication system and base station accommodation server

A communication system comprising a home server, an access gateway, and a policy server, wherein the policy server transmits, to the first access gateway, a link creation request for associating a communication path of the first terminal and a communication path of the second terminal; and the access gateway sets a fifth communication path which connects the first communication path and the third communication path upon receiving the link creation request, records information on the set fifth communication path in the communication path management information, and transmits the data from the first terminal via the first communication path to the second terminal via the fifth communication path and the third communication path based on the communication path management information.

Communication system and access gateway apparatus

A client signal having a constant bit rate is segmented every a bytes to create code information blocks. The bit rate of the client signal is increased such that the client signal has the code information block and an empty area comprised of b bytes, and the ratio c/a is equal to or higher than 110% to create a code blockcomprised of c bytes. The code information block in the code block is encoded such that an error correcting code is included therein to have an encoding gain of 6 dB or higher for a bit error ratio of 10. Associated check bits are placed in the empty area to eventually generate a super FEC signal.

Method for encoding/decoding error correcting code, transmitting apparatus and network

An optical transmission system accomplishes optical transmission over a long distance by combining a multiplexing line terminal with optical amplifiers, linear repeaters, and regenerators with optical amplifiers combined together. The system also accomplishes the optical transmission over a short distance by directly connecting the linear terminals therebetween, with an electric-to-optic converter replaced by an electric-to-optic converter having a semiconductor amplifier, with an optic-toelectric converter by an optic-to-electric converter having an avalanche photodiode as light receiver, and with no use of any optical booster amplifier and optical preamplifier in multiplexing line terminal. With these, the optical transmission system can be easily constructed depending on the transmission distance required.

Optical transmission system constructing method and system

An optical crossconnect apparatus which includes one terminal connected to a transmission path from one optical transmission terminal station and another terminal connected to a transmission path from another optical transmission terminal station, a first optical signal switch having 'M' ports and 'N' ports, through which the optical signal can pass, a second optical signal switch having &#x201c;M&#x201d; ports and &#x201c;N&#x201d; ports, through which the optical signal can pass, and &#x201c;L&#x201d; optical signal repeaters, one end connected to the &#x201c;N&#x201d; ports of the first optical signal switch, and the other end connected to the &#x201c;N&#x201d; ports of the second optical switch. The &#x201c;N&#x201d; and the &#x201c;N&#x201d; ports are equal to &#x201c;L&#x201d; optical signal repeaters. The &#x201c;M&#x201d; ports of the first optical signal switch connected to the one terminal, and the &#x201c;M&#x201d; ports of the second optical signal switch connected to the other terminal are larger than, or equal to 2.

Optical crossconnect apparatus and optical transmission system

An optical transmission network allows transmission monitoring zones to be set up or changed in a flexible manner, and allows simultaneous monitoring of communication quality for each of these monitoring zones. Also, provided is an optical transmission zone service provider that varies user fees according to communication quality in the used zones.

Method and apparatus for optical network administration

A router apparatusis provided with an ATM switch, an IP controller for performing routing control as a controller for layer, plural kinds of interfaces which are individually provided to plural transmission paths in which various communications are performed, and a cell multiplexing/demultiplexing unit, and manages the cell communications between respective parts on the basis of identification information. The input packet is subjected to IP processing in an interface to be converted to a cell in a common format, and the cell is serially multiplexed with a cell from another interface on a cell basis, and transmitted to the ATM switch at the cell multiplexing/demultiplexing unit. Each interface and each cell multiplexing/demultiplexing unit sets and switches the identification information for the header portion of the packet and the cell to be communicated by using a table in which the corresponding relationship of the identification information is registered.

Router apparatus using ATM switch

An optical one-to-one protection switching apparatus exchanges signals between a transmit node and a receive node. If a fault is detected in the first transmission line (down-stream), a controller in the node controls a drive circuit so as to shut off a gate. Then, the controller in the transmit node upon receiving a switching request from the receive node, controls the drive circuit so as to shut off the gate. Thereby, the optical switch is switched. The transmitter of the client terminal is thus connected to the second transmission line (down-stream). Upon receiving the switching request from the transmit node, the optical switch in the receive node is switched. Thereby the receiver in the client terminal is connected to the second transmission line (down-stream).

Optical one-to-one protection switching apparatus

An optical crossconnect apparatus which includes one terminal connected to a transmission path from one optical transmission terminal station and another terminal connected to a transmission path from another optical transmission terminal station, a first optical signal switch having &ldquo;M1&rdquo; ports and &ldquo;N1&rdquo; ports, through which the optical signal can pass, a second optical signal switch having &ldquo;M2&rdquo; ports and &ldquo;N2&rdquo; ports, through which the optical signal can pass, and &ldquo;L&rdquo; optical signal repeaters, one end connected to the &ldquo;N1&rdquo; ports of the first optical signal switch, and the other end connected to the &ldquo;N2&rdquo; ports of the second optical switch. The &ldquo;N1&rdquo; and the &ldquo;N2&rdquo; ports are equal to &ldquo;L&rdquo; optical signal repeaters. The &ldquo;M1&rdquo; ports of the first optical signal switch connected to the one terminal, and the &ldquo;M2&rdquo; ports of the second optical signal switch connected to the other terminal are larger than, or equal to 2.

An optical transmission system accomplishes optical transmission to a long distance by combining a multiplexing line terminal with optical amplifiers, linear repeaters, and regenerators with optical amplifiers combined together. The system also accomplishes the optical transmission to a short distance by directly connecting the linear terminals therebetween, with an electric-to-optic converter replaced by an electric-to-optic converter having a semiconductor amplifier, with an optic-to-electric converter by an optic-to-electric converter having an avalanche photodiode as light receiver, an with no use of any optical booster amplifier and optical preamplifier in the multiplexing line terminal. With these, the optical transmission system can be easily constructed depending on the transmission distance required.

Growing community of inventors

Yokohama, Japan

Masahiro Takatori