Patents Assigned to Hitachi Communication Technologies, Ltd.
  • Patent number: 8446816
    Abstract: In order to provide a redundancy configuration to an access gateway apparatus in which a control plane and a user plane are separated, the access gateway apparatus includes: a control computer for receiving control signals from the networks to establish the communication path, thereby determining packet transfer information for the data; and a transfer computer for receiving the packet transfer information from the control computer to transfer the data through the communication path. The transfer computer includes: a plurality of first transfer computers for executing the transfer of the data; and a second transfer computer for taking over, when a fault occurs in any one of the plurality of first transfer computers. The control computer includes: a first control computer for processing the control signals received from the networks; and a second control computer for taking over, when a fault occurs in the first control computer.
    Type: Grant
    Filed: June 15, 2009
    Date of Patent: May 21, 2013
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Takehiro Morishige, Tohru Setoyama
  • Patent number: 8280371
    Abstract: A radio system has silence periods in which wave transmission from a terminal is stopped and in which a base station measures external noise power. The base station includes a receiver for receiving a signal from the terminal, and a controller that has preset frequency information representing a frequency of diagnosing the receiver to a measurement frequency of external noise power, and diagnoses normality of the receiver by using one silence period out of plural silence periods on the basis of the frequency information while measuring the external noise power by using the other silence periods. When the receiver is diagnosed, the external noise cannot be measured during this silence period, and thus during this silence period the external noise measured during the just preceding silence period is held and applied as external noise under the diagnosis of the receiver.
    Type: Grant
    Filed: June 16, 2009
    Date of Patent: October 2, 2012
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Tatsuro Yasumi, Kei Fujiwara
  • Patent number: 8107461
    Abstract: The total system, which is operated by SIP (Session Initiation Protocol) call sequence and SIP call replacement sequence, comprises control part which includes sequence part for immediately performing the SIP call replacement sequence upon detecting communication of call forwarding or proxy response, SIP exchange equipment which includes storage part for storing sequence program of the call forwarding and proxy response, SIP telephones 3a to 3n, and a network such as Internet or wide LAN to which the SIP exchange equipment and SIP telephones 3a to 3n are connected, so that it is able to provide the SIP exchange system for agreeing a final party in communication and party number display, even an party responds the incoming call is changed by the call forwarding or proxy response.
    Type: Grant
    Filed: March 1, 2007
    Date of Patent: January 31, 2012
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Takahiro Sasaki, Kazuhiko Kubo
  • Patent number: 8036607
    Abstract: In a case where a switching source wireless communication system is a wireless communication system in which a transmission timing of a packet or data rate can be controlled in a wireless base station, the switching source wireless communication system, which notifies information on a timing when a wireless terminal communicates the switching destination wireless communication system with respect to the switching source wireless communication system in advance, starts time-division communication between switching destination and switching source wireless communication systems, and receives the timing information, controls a transmission timing or a data rate in accordance with the timing information.
    Type: Grant
    Filed: December 17, 2008
    Date of Patent: October 11, 2011
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Shiro Mazawa, Michio Iguchi, Takanori Moritomo, Masao Hayama
  • Patent number: 7996033
    Abstract: A radio communication system includes a grouping unit for grouping a plurality of base stations into a plurality of groups (Soft Handoff Groups) and a determining unit for selecting base stations belonging to one and the same group selected from the groups produced by the grouping unit and for determining the base stations as base stations to send communication packets to an access terminal.
    Type: Grant
    Filed: March 31, 2008
    Date of Patent: August 9, 2011
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Akihiko Yoshida, Shiro Mazawa, Kiyoshi Kawamoto, Yosuke Takahashi, Keiji Usuba
  • Patent number: 7830924
    Abstract: A unit timing signal synchronized with a high-order transmission frame is used for measuring a difference between the number of data pieces of a client signal mapped to the high-frequency frame and the number of data pieces of the output client signal by integrating the difference therebetween for each unit timing signal. Then stuffing and de-stuffing operations are performed so that a integration result is zero.
    Type: Grant
    Filed: May 29, 2007
    Date of Patent: November 9, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Kenji Kawamura, Takashi Funada, Masatoshi Shibasaki, Yoshimasa Kusano, Yusuke Honda, Hiromi Murakami
  • Patent number: 7796741
    Abstract: The invention provides a call connection control method which can use a conventional telephone as-is and performing linking with a low possibility of mistaking telephones, and a call connection control unit for implementing the method. Upon receiving an outgoing call request from an outgoing-call side personal computer (PC), a call connection control unit retrieves an outgoing-call side IP-telephone linked to the PC, and transmits an incoming call request to the IP-telephone. Upon receiving the incoming call request, the IP-telephone rings. When the caller places the IP-telephone that rings in a starting (off-hook) state, the call connection control unit sends a ring back tone to the IP-telephone and transmits an incoming call request to an incoming-call side IP-telephone. Upon receiving the incoming call request, the IP-telephone rings. When the recipient places the IP-telephone that rings in a starting state, the call connection control unit enables a call between the two IP-telephones.
    Type: Grant
    Filed: September 7, 2006
    Date of Patent: September 14, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Fumio Urayama, Tatsuya Yoshida, Shinji Saitou
  • Publication number: 20100226244
    Abstract: Provided is a multicast path management method for a connectionless communication. Also provided is a path protection function which is effective when a path has failed. A network is formed by a trunk and a branch path. The multicast path is managed by end-to-end and when a failure has occurred, an instruction is issued from the apex of the multicast tree to respective end-to-end paths so as to switch from the currently used channel to a backup path. Thus, upon failure, an individual path protection can be performed without affecting other parts of the tree to which the same multicast flow as the defective path is distributed or the distribution state of the multicast flow.
    Type: Application
    Filed: August 4, 2006
    Publication date: September 9, 2010
    Applicant: HITACHI COMMUNICATION TECHNOLOGIES, LTD.
    Inventors: Masahiko Mizutani, Atsushi Iwamura, Yoshihiro Ashi, Masayuki Takase, Hideki Endo
  • Patent number: 7756057
    Abstract: A radio communication terminal, being used in a radio communication systems in which the transmission rate varies depending on radio wave conditions and communication statuses of other users, comprises a reception module which receives packets transmitted by a base station in an idle state of the radio communication terminal, a signal processing module which estimates a transmission rate available in communication based on the packets received by the reception module, and a display module which displays information indicating the transmission rate estimated by the signal processing module.
    Type: Grant
    Filed: December 28, 2007
    Date of Patent: July 13, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Tsutomu Uchida, Hiroshi Tamaribuchi, Hideo Aoe, Masato Inagaki
  • Patent number: 7751381
    Abstract: To provide a wireless base station comprising an array antenna which transmits packets to terminals, a packet scheduler which determines transmission sequence of the packets, a modulator which generates modulated signals based on the packets, and a beam former for transmission signal which multiplies the packets with array weights for transmission signal and outputs the transmission signal to the array antenna the beam former for transmission signal comprises a memory which stores the array weights for transmission signal associated with the terminals' IDs. The beam former for transmission signal receives the IDs of selected terminals from the packet scheduler, refers to the memory, and selects the array weights for transmission signal by the IDs of the terminals.
    Type: Grant
    Filed: February 25, 2005
    Date of Patent: July 6, 2010
    Assignees: Hitachi, Ltd., Hitachi Communication Technologies, Ltd., Hitachi Advanced Systems Corporation
    Inventors: Mikio Kuwahara, Kenzaburo Fujishima, Masanori Taira, Koji Meguro, Toru Okamoto
  • Patent number: 7751394
    Abstract: An object of the present invention is to solve a problem that when multicast is utilized in a network configured with virtual routers, traffic in the relay network is increased. According to the present invention, the number of multicast packets via the relay network is reduced by performing a multicast packet transfer across the virtual routers within the same router. Specifically, it is allowed to register in a multicast routing table held by each virtual router, a line interface identifier of another virtual router as outgoing line interface information, whereby multicast packet transfer from a virtual router to another virtual router is made possible. In order to specify a virtual router to share the multicast packet, each virtual router holds information to specify a virtual router having a line interface to receive the multicast traffic indicated by the multicast group address.
    Type: Grant
    Filed: January 7, 2005
    Date of Patent: July 6, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Masatoshi Takihiro, Tetsuro Yoshimoto, Kengo Ijima
  • Patent number: 7729699
    Abstract: In a mobile communication system having an ATM-processed transfer path, a non-instantaneous interrupt handover can be realized. In a mobile communication network including an ATM-processed transfer path, when a mobile station is moved between cells during communication, frames are received to be identified by a mobile switching center. The frames contain the same data received from both base stations covering the cell range at asynchronous timing different from each other. A selection is made of header information with the lowest error rate from the header information of these frames. The frames are connected at instructed timing. Also, the frames to be transmitted to a plurality of base stations are duplicated, and then transmission timing is specified from these header information. These duplicated frames are transmitted at the specified transmission timing, so that the non-instantaneous interrupt handover is carried out.
    Type: Grant
    Filed: May 13, 2004
    Date of Patent: June 1, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Tsutomu Kusaki, Kenichi Sakamoto, Masaru Murakami, Takashi Yokoyama
  • Publication number: 20100113071
    Abstract: In a case where a cellular phone exists outside a WOS system service area, the cellular phone receives a not-connectable signal and an audio message from a mobile switching controller. The cellular phone conducts disconnection processing with the not-connectable signal as a turning point. Moreover, the cellular phone stores an extension number and converts a dedicated special number into an external number for retransmission, thus establishing connection to a PBX. After the reception of a connection-accepted signal and an automatic exchange answer message from the PBX, the cellular phone automatically transmits the stored extension number.
    Type: Application
    Filed: January 11, 2010
    Publication date: May 6, 2010
    Applicant: Hitachi Communication Technologies, Ltd.
    Inventors: Michio IGUCHI, Arata Nakagoshi, Ichiro Kohashi, Tsutomu Sano
  • Patent number: 7702366
    Abstract: Terminals #1 to #3 which have already been connected and a terminal #4 which wants to make a new connection send packets to a base station in that order. The base station queues the packets from the terminals #1 to #3 at a non-priority queue and the packet from the terminal #4 at a priority queue. For example, a predetermined amount of packets from a new connection is queued at the priority queue. Packets in the priority queue are dequeued with priority. Therefore, the packet sent from the terminal #4 is first sent to a base-station controller, and then the packets sent from the terminals #1 to #3 are sent to the base-station controller. As a result, the base-station controller first receives the packet sent from the terminal #4, and the period of time required for the terminal #4 to establish a connection is reduced.
    Type: Grant
    Filed: December 19, 2006
    Date of Patent: April 20, 2010
    Assignees: Hitachi Communication Technologies, Ltd., Hitachi Information & Communication Engineering, Ltd.
    Inventors: Takaaki Suzuki, Junpei Watanabe, Akio Kawase, Shingo Sasaki, Hideo Aoe
  • Patent number: 7697845
    Abstract: An optical add-drop function part of an optical add-drop multiplexer has an output end of transmitted light signal in which an optical termination mechanism formed by an optical detector for detecting open of an optical fiber, an optical switch, and an optical terminator are mounted. Further, a reflection level calculation circuit, a reflection warning determination circuit, and an optical switch selection circuit are mounted to perform laser safety in the optical add-drop function part as well. The laser safety part in the optical add-drop function part is operated earlier than the laser safety part in an optical amplification function part.
    Type: Grant
    Filed: May 23, 2007
    Date of Patent: April 13, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Yasuhiro Uchiyama, Hiroyuki Nakano
  • Publication number: 20100086304
    Abstract: A transmitting apparatus includes a plurality of code spreaders different in spreading code, a reception processing unit that selectively distributes transmission data to the plurality of code spreaders, a plurality of optical transmitters each of which that transmit a code-spread signal to an optical fiber as a CDMA optical signal of a carrier wavelength different from that of the other optical transmitters, and a signal multiplexing unit that selectively supplies outputs of the plurality of code spreaders to the plurality of optical transmitters, and a receiving apparatus includes an optical receiver that receives a wavelength-division-multiplexed CDMA optical signal from the optical fiber, and a plurality of despreaders connected to the optical receiver and different in spreading code, wherein each of the despreaders reproduces a CDMA signal corresponding to its spreading code from an output signal of the optical receiver.
    Type: Application
    Filed: October 6, 2006
    Publication date: April 8, 2010
    Applicant: HITACHI COMMUNICATION TECHNOLOGIES, LTD.
    Inventors: Masahiko Mizutani, Yoshihiro Ashi, Shinya Sasaki, Tohru Kazawa
  • Publication number: 20100067910
    Abstract: Provided is an ONU that suppresses transmission of a useless multicast control message to a PON section and enables a communication bandwidth of the PON section to be effectively used. The ONU of the PON system has a multicast group management table that shows a correspondence between a multicast group identifier and an address of a user terminal participating in a multicast group. When the ONU receives a request message of participation in the multicast group from the user terminal, the ONU registers the correspondence between the multicast group identifier indicated by the received message and the user terminal address. A new received message is deleted without being sent to the OLT if another user terminal address is registered already, along with a correspondence with the same multicast group identifier, in the multicast group management table.
    Type: Application
    Filed: November 19, 2009
    Publication date: March 18, 2010
    Applicant: HITACHI COMMUNICATION TECHNOLOGIES, LTD.
    Inventors: Masahiko Mizutani, Takeshi Shibata, Tohru Kazawa, Yoshihiro Ashi, Masanobu Kobayashi, Masayuki Takase
  • Patent number: 7680414
    Abstract: A Passive Optical Network system implementing a parent station capable of receiving high-speed burst signals transmitted from a plurality of subsidiary stations to a parent station, with excellent bandwidth utilization efficiency in the link from the stations to the parent. The system is provided with a configuration in which, when launched or an addition of a new subsidiary station, the parent stores threshold values appropriate for the received signals on the basis of the strength of the received signal for each subsidiary station, from among a plurality of preset threshold value candidates, and in response to the parent station's sending of a transmission grant with respect to each subsidiary station each time the subsidiary station transmitting optical signals changes, the stored threshold value corresponding to the subsidiary station is set in the receiver circuit.
    Type: Grant
    Filed: May 30, 2007
    Date of Patent: March 16, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Tohru Kazawa, Masaki Ohira, Yusuke Yajima
  • Publication number: 20100062787
    Abstract: The present invention implements communication control with user's service subscription information reflected in a mobile communication network. A QoS control server for providing a communication quality control function of a network, a user information management server for managing user's service information, a service proxy server for transferring a service control message transmitted by a user to a service control server, a service relay server for relaying a message between service control servers in two different networks, and a service control server for exercising service control based on user service information are included. In user service start processing, the service control server or service relay server transmits a service control message inclusive of service subscription information acquired beforehand to the service proxy server. The QoS control server acquires the service subscription information from the service proxy server.
    Type: Application
    Filed: February 28, 2007
    Publication date: March 11, 2010
    Applicant: HITACHI COMMUNICATION TECHNOLOGIES, LTD.
    Inventors: Hideya Yoshiuchi, Masashi Yano, Hitomi Nakamura
  • Patent number: 7676127
    Abstract: In a PON system, an OLT periodically transmits a channel resource information block specifying a carrier wavelength and a spreading code on a first downstream channel to which a spread-spectrum spreader having a first spreading code is applied; one of ONUs receives the channel resource information block with a spread-spectrum despreader having the first spreading code and transmits a connection request to the OLT, using the carrier wavelength and the spreading code specified by the channel resource information block; the OLT having received the connection request transmits a new channel resource information block specifying a carrier wavelength and a spreading code to be used on an upstream data channel to the requester ONU through the first channel; and the requester ONU transmits data, using the carrier wavelength and the spreading code specified by the new channel resource information block.
    Type: Grant
    Filed: September 20, 2007
    Date of Patent: March 9, 2010
    Assignee: Hitachi Communication Technologies, Ltd.
    Inventors: Masahiko Mizutani, Toshiki Sugawara, Tohru Kazawa, Yoshihiro Ashi