Patents Assigned to NTT Mobile Communication Network Inc.
  • Patent number: 5841767
    Abstract: A service area expansion scheme for a mobile communication system, capable of efficiently connecting thinly populated areas (satellite zones) to a mobile communication network so as to expand the service area of the mobile communication system economically. In expanding the service area, remote base stations are set at thinly populated areas, while a remote mobile local switching station for connecting the remote base stations to the mobile communication network is provided. The remote base stations and the remote mobile local switching station are selectively connected through the public network by using the respective channel connection units for providing connections with the public network. The remote base stations and the remote mobile local switching station can be replaced by satellite base stations and a satellite mobile local switching station for connecting the satellite base stations to the mobile communication network.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: November 24, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Yasuki Nishi, Kazuhito Ebina, Susumu Ueno
  • Patent number: 5838671
    Abstract: A call admission control scheme for a CDMA mobile communication system which can satisfy a given connection quality (blocking probability) while guaranteeing a predetermined communication quality. At each base station, a blocking probability and an outage probability of communication quality at each base station are calculated to adjust a maximum number of simultaneously connectable users at each base station according to the calculated results, and a call admission control is carried out according to the adjusted maximum number of simultaneously connectable users.
    Type: Grant
    Filed: June 18, 1996
    Date of Patent: November 17, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Yoshihiro Ishikawa, Narumi Umeda
  • Patent number: 5835023
    Abstract: In a mobile radio communication system wherein, in order to call a receiver from a base station, a paging signal containing address information corresponding to the receiver to be called is transmitted n times, the position of a paging signal that is transmitted for the second or subsequent time is determined, in accordance with a prearranged rule, in relation to the position of the same paging signal when it was transmitted for the first time, and the receiver achieves more efficient battery savings by stopping its receiving operation with respect to signal portions which have been confirmed as having already been received without error. The receiving operation is intermittently stopped at a timing corresponding to identical signal portions of the same repeatedly received paging signal.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: November 10, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Shogo Ito, Yoshiaki Hirai, Nobuyuki Nanba, Toshihiro Nozawa
  • Patent number: 5835846
    Abstract: A transmission power control method in a mobile satellite communication system implementing accurate control of transmission power of a base station by obtaining an average received signal level at a mobile station at high accuracy. The mobile station measures an average received signal level Q.sub.k in a predetermined period (step SP2), and informs the base station of the average received signal level Q.sub.k and an actual measuring time T.sub.k (step SP3). The base station calculates a total measuring time t.sub.k which is the sum total of the actual measuring time T.sub.k (step SP16), a corrected average received signal level R.sub.k associated with the average received signal level during the total measuring time t.sub.k (step SP18), and a measuring error .DELTA.D.sub.k (step SP17), and controls the transmission power on the basis of these values (step SP21). Estimating the measuring error .DELTA.D.sub.k in the total measuring time t.sub.k longer than the individual actual measuring time T.sub.
    Type: Grant
    Filed: December 12, 1995
    Date of Patent: November 10, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Kenji Furukawa, Yasuki Nishi, Hiroshi Kobayashi, Yoshihisa Ohno, Eiji Kodama
  • Patent number: 5832368
    Abstract: A base station selection scheme for a CDMA cellular system capable of reducing the transmission power of the mobile station and increasing the subscriber capacity, by accounting for the uplink interference power at each base station. An uplink interference level is measured at each base station, while a perch channel is transmitted from each base station to the mobile station, and a perch channel reception level of the perch channel transmitted from each base station is measured at the mobile station. Then, a connection target base station to be connected with the mobile station is selected according to a received SIR (Signal to Interference Ratio) of each base station determined from the perch channel reception level measured at the mobile station and the uplink interference level measured at each base station.
    Type: Grant
    Filed: December 12, 1996
    Date of Patent: November 3, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Etsuhiro Nakano, Akihiro Higashi, Fumio Kikuchi
  • Patent number: 5828958
    Abstract: A mobile communications system including a plurality of communications networks, each of which has one location register (a home location register or gate location register) and one or more visitor registers. Each of the visitor registers is located in each one of visiting areas for storing information about a communication terminal. The location register stores the number of the visitor register of the visiting area in which the communication terminal is present, and the information about the communication terminal. When the communication terminal moves between the communications networks, the information about the communication terminal is transferred between the location registers. When the communication terminal moves between the visiting areas in the same communications network, the information about the communication terminal is provided from the location register to the visitor register.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: October 27, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: So Ishida, Hiroshi Nakamura, Yasuyuki Uchiyama
  • Patent number: 5826172
    Abstract: In a system which transmits the same paging signals a plurality of times through the air by radio waves, paging signals serve to selectively page radio receivers. Base station facilities can be deployed at a comparatively low cost even when there are few customers per service area by variably setting the number of times that the paging signals are transmitted from the base stations.
    Type: Grant
    Filed: October 2, 1995
    Date of Patent: October 20, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Shogo Ito, Yasushi Yamao, Shinzo Ohkubo
  • Patent number: 5826197
    Abstract: A mobile communication system having a high precision frequency base station device with a high precision frequency generator, and the other low precision frequency base station device with a low precision frequency generator which receives transmission waves from the high precision frequency base station device using a transmission frequency in a prescribed frequency precision, and carries out transmission and reception by controlling transmission and reception frequencies of own station in accordance with the frequency precision of the received transmission waves.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: October 20, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Kiyohito Nagata, Teruya Fujii, Katsunori Hamada, Kazuhiko Kakinuma, Masaaki Yoshimi, Tatsuaki Wakabayashi
  • Patent number: 5822701
    Abstract: Centralized controlling apparatus controls overall flow of signals. Calling apparatus transmits a call signal in response to a call instruction signal transmitted from the centralized controlling apparatus. Information receiving apparatus receives the call signal to transmit an answer signal. Answer receiving apparatus transmits an answer acknowledge signal when it receives the answer signal. The centralized controlling apparatus transmits an information/control signal to information transmitting/distributing apparatus when it receives the answer acknowledge signal. The information transmitting/distributing apparatus distributes the information/control signals to a plurality of information transmitting apparatus. The plurality of information transmitting apparatus transmits simultaneously the information signals to the information receiving apparatus by radio.
    Type: Grant
    Filed: August 27, 1996
    Date of Patent: October 13, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Shigeru Tomisato, Hiroshi Suzuki, Kenkichi Hirade
  • Patent number: 5815812
    Abstract: The present invention provides a system for soft handoff, which processes in high speed. A system according to the present invention substantially realizes a multiplication by a circuit for classifying received signals from a plurality of cell site stations once held in an analog sampling and holding circuit into two groups, multiplication and accumulation, by a small circuit of low electric power consumption.
    Type: Grant
    Filed: December 5, 1996
    Date of Patent: September 29, 1998
    Assignees: NTT Mobile Communications Network, Inc., Yozan, Inc.
    Inventors: Changming Zhou, Guoliang Shou, Makoto Yamamoto, Mamoru Sawahashi, Fumiyuki Adachi, Sunao Takatori
  • Patent number: 5815680
    Abstract: Datapath elements 1.sub.1 to 1.sub.N can exchange data respectively with local memories 2.sub.1 to 2.sub.N through data buses 6.sub.1 to 6.sub.N, so that parallel operations can be performed. The data bus 6.sub.1, which is connected with one datapath element 1.sub.1, can be connected with the other data buses 6.sub.2 to 6.sub.N through an interconnection network 5, so that by activating one datapath element 1.sub.1 only, data exchange can be made with all of the local memories 2.sub.1 to 2.sub.N through the data buses 6.sub.1 to 6.sub.N and the interconnection network 5. Thus, the multiple datapath elements can perform the parallel operations with being related with the multiple local memories: and a simple configuration is employed such that one datapath element can access to any one of the local memories.
    Type: Grant
    Filed: October 25, 1995
    Date of Patent: September 29, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Yukihiko Okumura, Toshio Miki, Tomoyuki Ohya, Yoshinori Miki
  • Patent number: 5812198
    Abstract: This invention relates to a video coding decoding apparatus for effectively refreshing a video and for recovering degradation of a video caused by code error, in a short time. A video coding decoding apparatus according to the present invention comprises area shape detection (12) for dividing the picture in the single frame into a motion compensation area and the remaining area and then detecting a shape of the motion compensation area by distinguishing between the motion compensation area and the remaining area, and motion vector estimation (14) for estimating a resultant motion vector of the overall motion compensation area from a motion vector of each block in the motion compensation area. A refreshing operation is carried out from a starting point of the estimated resultant motion vector towards the direction of the estimated resultant motion vector in a motion compensation area.
    Type: Grant
    Filed: September 30, 1996
    Date of Patent: September 22, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Masahito Saigusa, Toshio Miki
  • Patent number: 5812296
    Abstract: In a fiber optics transmission system in which a plurality of access units are cascade-connected via up-link and down-link optical fiber lines and connected to a base unit, the base unit has a beat noise detector and a noise information generator and, upon detection of beat noise, noise information is sent to each access unit over the optical fiber lines. Each access unit has a random signal generator for generating a random value in response to the noise information and a wavelength control circuit for randomly selecting and controlling the oscillation wavelength of a laser diode, and each access unit repeats random wavelength selection until the noise information is reduced.
    Type: Grant
    Filed: February 11, 1997
    Date of Patent: September 22, 1998
    Assignee: NTT Mobile Communications Networks Inc.
    Inventors: Yoshiaki Tarusawa, Toshio Nojima, Yasushi Ito
  • Patent number: 5805076
    Abstract: In a mobile communications system wherein the transmission form changes in the course of the signal, high quality transmission of change information relating to the transmission form is obtained. To achieve this, information giving advance notice of a change is transmitted prior to transmitting the change information relating to the transmission form. Even if a situation arises in which transmitted information has not been conveyed without error at a scheduled change time that was notified in advance, it is possible to resolve this situation by referring to the information giving advance notice of the change. This enables faulty paging and other defects resulting from erroneous changes of transmission form to be reduced.
    Type: Grant
    Filed: March 19, 1996
    Date of Patent: September 8, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Shogo Ito, Yasushi Yamao
  • Patent number: 5805078
    Abstract: A mobile communications network and a mobile communication method for reducing loads to be incurred to the mobile communications network which loads occur because the user changes its mobile communication terminal. Mobile communication terminal numbers of mobile communication terminals (21), (22), IDs of users (31), (32) of the mobile communication terminals, and at least one address to be used by each user when the user performs a communication. The mobile communications network comprises an address/user corresponding table (13) having a table for bringing addresses to be used in each of the multiple communication methods and a user ID into corresponding relation. When a terminating request specifying an address is made, a user ID corresponding to the specified address is obtained using the address/user corresponding table.
    Type: Grant
    Filed: June 12, 1996
    Date of Patent: September 8, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Kazuo Sugiyama, Shoichi Hirata, Yasushi Nakamura
  • Patent number: 5802471
    Abstract: This invention provides a mobile communication system in which a call-incoming side can switch a communication line to an appropriate one which corresponds to a communication type requested by a transmitter's terminal. One example of its construction is as follows.A mobile station has a plurality of terminal units corresponding to plural types of communication and a call number is preliminarily assigned to each of them. A terminal unit in a telephone network uses a call number corresponding to a desired communication type when a datum is transmitted to the mobile station. The mobile station informs this call number to all of the terminal units which are connected to the mobile station. The respective terminal units inform the communication type to the mobile station only when the communication type corresponding to the call number can be handled. The mobile station informs this communication type contained in a reception call receiving signal to a mobile communication exchange.
    Type: Grant
    Filed: December 26, 1995
    Date of Patent: September 1, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Koichi Sawai, Kunio Yoshikawa, Yukiya Miyasita
  • Patent number: 5796307
    Abstract: An input signal is applied to a first phase shifter whose phase shift amount-vs.frequency characteristic is a square-law characteristic, then the output from the first phase shifter is amplified by an amplifier, and the amplified output is applied to a second phase shifter which has a phase shift amount-vs.-frequency characteristic that is substantially inverse to that of the first phase shifter, thereby obtaining an amplified output signal from the second phase shifter.
    Type: Grant
    Filed: November 14, 1996
    Date of Patent: August 18, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Ken Kumagai, Toshio Nojima, Shoichi Narahashi
  • Patent number: 5794124
    Abstract: A system wherein time diversity reception is performed for each error-corrected or error-detected code word without distinguishing between the address signal and the message signal, the code words being the units which make up the address and message signals. A received signal comprising correctly decoded code words is obtained by selecting code words that are judged to have been correctly decoded in accordance with error detecting/correcting logic from among code words with the same content that have been received a plurality of times. When a code word has been correctly decoded, part of the selective radio paging receiver is inhibited from working during the time intervals when correctly received code words would be received, thereby decreasing battery consumption.
    Type: Grant
    Filed: November 13, 1995
    Date of Patent: August 11, 1998
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Shogo Ito, Yasushi Yamao, Shinzo Ohkubo
  • Patent number: 5790555
    Abstract: The frequencies of input modulated signals fed via ports 11.sub.1 to 11.sub.n are converted by frequency converting parts 12.sub.1 to 12.sub.n to different bands, and the converted outputs are applied to power combining part 24 decides if 16 via variable attenuators 21.sub.1 to 21.sub.n, respectively, and provided therefrom as a multiplexed output a portion of which is branched. The envelope power level L is detected by level detecting part 23. Control with the detected level L exceeds a level L.sub.s that is k times the average power of the multiplexed signal k being about 4 to 5, and controls the attenuators 21.sub.1 to 21.sub.n to attenuate the average power of the modulated signal by k/n-fold or less for about 1/.DELTA.F.sub.0 (sec), where (.DELTA.F.sub.0 ?Hz! is the frequency bandwidth of the multiplexed signal.
    Type: Grant
    Filed: June 7, 1996
    Date of Patent: August 4, 1998
    Assignee: NTT Mobile Communications, Network Inc.
    Inventors: Shoichi Narahashi, Ken Kumagai, Toshio Nojima, Yoshiaki Tarusawa
  • Patent number: 5790588
    Abstract: In a system with a spread spectrum transmitter and receiver employing composite spreading codes, the transmitter spreads, in a spreading part, a baseband modulated signal by a short code from a short code generator and a long code from a long code generator with a longer chip period than that of the short code and then transmits the spread baseband modulated signal. The receiver despreads a spread baseband received signal in a receiving part by a pair of short and long codes in one despreading part to obtain a baseband modulated signal of a direct path and despreads the spread baseband received signal by the pair of short and long codes delayed by a multipath delay time difference in the other despreading part to obtain a baseband modulated signal of a delayed path, and the baseband modulated signals thus obtained are diversity-detected to obtain a detected baseband signal.
    Type: Grant
    Filed: June 4, 1996
    Date of Patent: August 4, 1998
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Kazuhiko Fukawa, Hiroshi Suzuki