Patents by Inventor Masao Niibe

Masao Niibe has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8824894
    Abstract: When an ONU accommodating range is enlarged, and ONUs shorter and ONUs longer in a communication path to an OLT are accommodated in a PON at the same time, there is a need to change a light intensity at the time of transmitting a downstream signal in order that both of the ONUs receive a downstream signal from the OLT. When a near-end ONU receives a signal having a light intensity necessary to communicate between the OLT and a far-end ONU, there arises such a problem that the light intensity is as high as an ONU receiver fails. In order to eliminate the ONU failure of the above problem, prior to transmission of the downstream signal, a downstream signal transmission schedule (downstream light intensity map) is notified to all of the ONUs. An optical transceiver of the OLT has a function of adjusting an output light intensity, and adjusts the light intensity to values receivable by the individual ONUs when the signal arrives at the respective ONUs according to route distances to the respective ONUs.
    Type: Grant
    Filed: August 30, 2011
    Date of Patent: September 2, 2014
    Assignee: Hitachi, Ltd.
    Inventors: Masao Niibe, Masahiko Mizutani
  • Publication number: 20140098676
    Abstract: When a communications carrier uses another company's network as a relay network, it is necessary to monitor the health of and to perform maintenance for the lines from end to end in the other company's network as well as the network managed by this carrier. Terminal devices capable of terminating a CCM frame or other OAM signal are installed in users bases, and the health is monitored from end to end between the bases. Furthermore, a control device that controls the terminal devices is installed in the VLAN network used by the user, and remote control of the terminal devices is implemented from the controller. Table information held by the controller is managed collectively under the leadership of an operator, and information about the subordinate terminal devices connected to the controller is reported to the operator on the basis of results of the MAC learning by the controller.
    Type: Application
    Filed: April 2, 2012
    Publication date: April 10, 2014
    Applicant: HITACHI, LTD.
    Inventors: Akihiko Tsuchiya, Masao Niibe, Takayuki Kanno, Yoshihiro Ashi
  • Patent number: 8391715
    Abstract: When a neighbor ONU receives a signal with light intensity high enough to secure communication between an OLT and a remote ONU, the light intensity may be excessively high to damage a receiver of the neighbor ONU. In order to avoid such a problem, each ONU is notified of a downstream signal transmission plan (downstream light intensity map) prior to transmission of a downstream signal. Each ONU receives the downstream light intensity map (light intensity transmission schedule of downstream signal) in advance. Thus, the neighbor ONU can block or attenuate an optical signal addressed to the remote ONU, and the remote ONU can determine normal operation even when the remote ONU cannot receive a signal addressed to the neighbor ONU. Thus, the remote ONU can be prevented from issuing a wrong error signal.
    Type: Grant
    Filed: March 25, 2011
    Date of Patent: March 5, 2013
    Assignee: Hitachi, Ltd.
    Inventors: Masao Niibe, Masahiko Mizutani, Shinya Fujioka
  • Patent number: 8184975
    Abstract: In a passive optical network system in which signals from a master station to plural slave stations are time-division multiplexed and transmitted, the slave stations different in transmission speed are mixedly contained. The master station (OLU) performs ranging for each transmission speed, and grasps all the slave stations different in transmission speed for each transmission speed, and generates a frame including signals of a suitable transmission speed corresponding to each slave station. When the frame is generated, in a downstream signal in which signals of plural transmission speeds are mixed, a dummy signal is set at a place where the transmission speed is changed, and a time necessary to follow a change in level of a received signal due to a change in optical level caused when the transmission speed is changed is secured. Thereby, each ONU avoids a reception error occurring in the time necessary to follow.
    Type: Grant
    Filed: February 18, 2009
    Date of Patent: May 22, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masao Niibe, Tohru Kazawa, Takeshi Kiyose, Ryosuke Nishino
  • Publication number: 20120087662
    Abstract: The OLT manages information of optical intensity and communication bit rate receivable by each ONU, and transmits a signal at suitable optical intensity and a bit rate. The OLT decides a signal transmission plan for each ONU according to a status of accumulated information waiting to be transmitted in the OLT's own device buffer, and inserts the signal transmission plan in a header or payload of a downlink frame, thereby notifying the ONUs of the information prior to transmitting accumulated information (primary signal). The ONU recognizes the signal transmission plan of the OLT according to the time information in a downlink intensity map, receives only a signal having the optical intensity and bit rate suitable for the ONU's own device, and blocks other signals.
    Type: Application
    Filed: September 22, 2011
    Publication date: April 12, 2012
    Inventors: Katsuyoshi Suzuki, Masao Niibe, Shinya Fujioka, Masahiko Mizutani
  • Patent number: 8145055
    Abstract: In a PON, at the time of ranging, an OLT (a master station) measures an optical level of a signal from at least an ONU (a slave station) capable of communicating at plural transmission speeds. The OLT determines the transmission speed applied to the ONU according to the measured level. Incidentally, the ONU may measure an optical level of a ranging request signal and determine the transmission speed. At a normal operation, when the OLT sends information of plural different transmission speeds to the ONU, a timing when a next frame reaches and transmission speed information are notified to the ONU. Based on the timing, the ONU receives only data of the transmission speed that can be handled. Besides, the OLT switches the transmission speed to receive data based on a grant designation transmitted from the plural ONUs to the OLT.
    Type: Grant
    Filed: February 20, 2009
    Date of Patent: March 27, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masao Niibe, Masahiko Mizutani, Tohru Kazawa
  • Patent number: 8139950
    Abstract: A passive optical network system (PON) has a plurality of OLTs and ONUs with different transmission rates. OLTs with different transmission rates share information of priority frames and destinations, and determine timing for frame transmission to ONUs so that the signal from each of the OLTs does not collide when multiplied in a splitter. OLTs transmit the data to the ONU as a burst signal to prevent the signals with different rates from colliding. ONU acquires the information of the following burst frames. ONU receives only the signal addressed to the own ONU or with the transmission rate of own ONU, therefore errors in ONUs can be avoided. OLT receives only the signal with the transmission rate of own OLT from ONUs based on the transmission timing from the ONUs shared by the line terminators, errors in OLTs can be avoided.
    Type: Grant
    Filed: May 15, 2008
    Date of Patent: March 20, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Masao Niibe, Tohru Kazawa, Yusuke Yajima, Takeshi Kiyose, Masahiko Mizutani
  • Publication number: 20100067913
    Abstract: In a passive optical network system in which signals from a master station to plural slave stations are time-division multiplexed and transmitted, the slave stations different in transmission speed are mixedly contained. The master station (OLU) performs ranging for each transmission speed, and grasps all the slave stations different in transmission speed for each transmission speed, and generates a frame including signals of a suitable transmission speed corresponding to each slave station. When the frame is generated, in a downstream signal in which signals of plural transmission speeds are mixed, a dummy signal is set at a place where the transmission speed is changed, and a time necessary to follow a change in level of a received signal due to a change in optical level caused when the transmission speed is changed is secured. Thereby, each ONU avoids a reception error occurring in the time necessary to follow.
    Type: Application
    Filed: February 18, 2009
    Publication date: March 18, 2010
    Inventors: Masao Niibe, Tohru Kazawa, Takeshi Kiyose, Ryosuke Nishino