Patents by Inventor Akihiro Higashi

Akihiro Higashi 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).

  • Publication number: 20020181558
    Abstract: An EOR (XR11, XR12) of outputs from a plurality of shift stages S1, S2, S4 of an M-series generator 31A is formed, thereby obtaining an M-series which has a desired delay, which in an example is a three bit delay with respect to the output code from the generator 31A. Similarly, outputs from a plurality of shift stages are combined and an EOR thereof is formed to provide another delayed M-series. An EOR of each output from the simultaneously delayed code generator 31 and an output from other M-series generator 32 is formed, thus simultaneously obtaining a plurality of Gold code series.
    Type: Application
    Filed: June 21, 2002
    Publication date: December 5, 2002
    Applicant: NTT Mobile Communications Network, Inc.
    Inventors: Shinsuke Ogawa, Hirofumi Takagi, Akihiro Higashi
  • Publication number: 20020071408
    Abstract: A control for varying a maximum transmission power of a transmitter according to a propagation loss or a distance between the transmitter and a receiver is made possible to reduce deterioration of a user capacity to a minimum. In a wave propagation loss measurement section, a calculation is performed on the basis of an amplification factor of a reception amplifier, amplitude information and a base station transmission power information of a reception baseband signal to calculate a wave propagation loss of a reception signal, thereby estimating a propagation loss of transmission signal. The wave propagation loss information is inputted to a maximum amplification amount designation circuit to decide a maximum amplification factor. The maximum amplification amount designation circuit djusts a maximum transmission power of the transmission signal by designating the decided maximum amplification factor to a transmission amplifier.
    Type: Application
    Filed: September 12, 2001
    Publication date: June 13, 2002
    Inventors: Shinsuke Ogawa, Yukihiko Okumura, Akihiro Higashi
  • Publication number: 20020073332
    Abstract: Information stored in an IC card which can be set to a block state, where any functions permitted to a user authority holder is not effective and an unblock password is required to set the IC card back to an initial state, is more secured than that stored in an IC card without the block state. The IC card of the present invention is further provided with a counter counting the number of incorrect unblock passwords, and is set to a more secured state of operation where only administrative authority holder can release the IC card.
    Type: Application
    Filed: December 12, 2001
    Publication date: June 13, 2002
    Applicant: NTT DoCoMo, Inc.
    Inventors: Hidetoshi Ishikawa, Yukio Yamauchi, Kanehiro Imai, Akihiro Higashi
  • Patent number: 6343218
    Abstract: A mobile station according to the present invention that is capable of connecting simultaneously to a plurality of base stations comprises a reception radio portion and TPC bit detecting portions, for receiving and detecting TPC bits (transmission power control signals) from the plurality of base stations during soft handover; a combining portion, for combining the detected TPC bits to determine a combination signal; and a transmission power control deciding portion, for controlling the transmission power of the mobile station based on the combination signal determined by the combining portion. A method according to the present invention governs use of the mobile station hereof.
    Type: Grant
    Filed: September 16, 1999
    Date of Patent: January 29, 2002
    Assignee: NTT Docomo Inc.
    Inventors: Ryusuke Kaneda, Seiji Hagiwara, Akihiro Higashi
  • Patent number: 6188682
    Abstract: A receiving method using a CDMA radio receiver with a plurality of receiving fingers each composed of a code generator, a correlator and a detector. In a visited cell search while in the ON-state of the power supply, different long-period spreading codes are set in the code generators, and if none of correlated outputs from the correlators respectively corresponding to the code generators exceed a threshold value, then new different long-period spreading codes are set in the code generators. If any one of the correlator outputs exceeds the threshold value, the mobile station is decided as staying in the cell corresponding to the long-period spreading code set in that correlator, and this long-period spreading code and time points at which peaks of correlator outputs were obtained with the long-period spreading code are set in the receiving fingers in descending order of the magnitude of correlation peaks.
    Type: Grant
    Filed: July 17, 1997
    Date of Patent: February 13, 2001
    Assignee: NTT Mobile Communication Networks, Inc.
    Inventors: Hirofumi Takagi, Akihiro Higashi
  • Patent number: 6167037
    Abstract: Achieving high speed spreading code synchronization of a forward link control channel. A control channel information signal and traffic channel information signals are each spread by different first spreading codes which are fed from a first spreading code (short code) generator (11), and which have a period equal to the period of an information symbol. Subsequently, only the control channel information signal is spread by a third spreading code which is fed from a third spreading code (long code masked portion complex conjugate code) generator (12), and which has a form of complex conjugate of a long code (second spreading code) used for spreading in common. The signals of the entire channels are summed up by an adder (13) at appropriate timings, and the resultant sum is spread by the second spreading code fed from a second spreading code generator (14), thereby being output as a spread modulation signal.
    Type: Grant
    Filed: November 3, 1997
    Date of Patent: December 26, 2000
    Assignee: NTT Mobile Communications Networks Inc.
    Inventors: Kenichi Higuchi, Mamoru Sawahashi, Fumiyuki Adachi, Koji Ohno, Akihiro Higashi
  • Patent number: 6026115
    Abstract: A RAKE receiver which is employed in a direct sequence spread spectrum communication system, and which can effectively receive multipath signals. A path searcher measures the amplitude of each path, selects N paths with larger amplitudes in descending order of magnitude, where N is the number of despreaders, and assigns the despreaders to the selected paths to despread the signals of the paths. This assignment of the despreaders to the paths is carried out such that a path with a large amplitude and a path with a small amplitude are assigned to adjacent despreaders and are input to the same pre-detection combiner. The outputs of the despreaders are combined by the pre-detection combiners, and detected by detectors whose outputs are RAKE combined by a post-detection combiner.
    Type: Grant
    Filed: August 18, 1997
    Date of Patent: February 15, 2000
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Akihiro Higashi, Koji Ohno, Seizou Onoe
  • Patent number: 5940433
    Abstract: In a mobile communication system using spread spectrum, performing respective multiplications of an I and Q channel signals by a spreading code replica, integration over one spreading code period, and square-law detection of the integrated signals to remove data modulation components and residual carrier frequency components. The square-law detected signals are added to obtain signal power over one spreading code period while updating the clock phase of a digital control clock generator. The information of power is stored in a memory in an acquisition mode controller, and the clock phase of the digital control clock generator 30 is fixed at the spreading code replica phase at which a maximum correlation detection power over one spreading code period is obtained. Subsequently, a confirmation mode is started for confirming the spreading code acquisition phase.
    Type: Grant
    Filed: February 12, 1997
    Date of Patent: August 17, 1999
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Mamoru Sawahashi, Akihiro Higashi, Kenichi Higuchi
  • Patent number: 5896374
    Abstract: A variable rate transmission method that can vary the transmission rate of data. A transmitting side supplies a transmitted data sequence to an error detecting encoder 105 and a frame memory 103. The frame memory 103 stores data of a variable length to be transmitted in one frame. The error detecting encoder 105 calculates an error detecting code (such as CRC code) for each frame of the transmitted data. A multiplexer 104 adds the calculated error detecting code ahead of the transmitted data to place it at the initial position of the frame, and sequentially outputs the data sequence frame by frame. A receiving side calculates an error detecting code of the data in each transmitted frame in the same manner as the transmitting side, and compares the calculated error detecting code with the error detecting code at the initial position of the frame. The end bit of the frame data is decided as a position at which the two error detecting codes coincide.
    Type: Grant
    Filed: October 22, 1996
    Date of Patent: April 20, 1999
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Yukihiko Okumura, Fumiyuki Adachi, Koji Ohno, Akihiro Higashi
  • 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: 5692015
    Abstract: A coherent detection method including a step of estimating a transfer function of a propagation path using pseudo-pilot signals which consist of some information symbols adjacent to pilot signals. The information symbols in the pseudo-pilot signals are assumed to be known. The method includes the steps of estimating the transfer functions using the pilot signals, carrying out interpolation coherent detection of the information symbols using the estimated transfer functions, storing the detection results as the pseudo-pilot signals, reestimating the transfer functions associated with the information symbols corresponding to the pseudo-pilot signals by using the pseudo-pilot signals and the corresponding received signal under the assumption that the pseudo-pilot signals have a known correct pattern, and carrying out the interpolation coherent detection of the individual information symbols by using the transfer functions obtained by the reestimation.
    Type: Grant
    Filed: November 28, 1995
    Date of Patent: November 25, 1997
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Akihiro Higashi, Fumiyuki Adachi, Koji Ohno, Mamoru Sawahashi
  • Patent number: 5673260
    Abstract: CDMA mobile communication method and system for realizing an autonomous distributed control of radio channel allocation, a synchronization control for a smooth establishment/switching, and a VOX control for a capacity increase are provided. At either one station of each base station and the mobile station, one of a plurality of prescribed short spread codes is selected, and a data sequence to be transmitted is spread by using the selected short spread code and a prescribed long spread code and then transmitted, while at another one station, the data sequence before spreading is reproduced and received by despreading the data sequence from that either one station by using the selected short spread code and the prescribed long spread code.
    Type: Grant
    Filed: October 5, 1995
    Date of Patent: September 30, 1997
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Narumi Umeda, Akihiro Higashi, Akira Hiroike, Akira Kaiyama
  • Patent number: 5652765
    Abstract: A repeater improving the effect of a RAKE reception. A received signal from a base station parallelly passes a first path including a first delay circuit and a second path including no delay circuit, and is transmitted to a mobile station. A received signal from the mobile station parallelly passes a third path including a second delay circuit and a fourth path including no delay circuit, and is transmitted to the base station. The delay time of the delay circuits are set at one chip interval or more of a spreading code. This forcedly produces multipath waves which are resolvable by a RAKE receiver. The RAKE receiver estimates amplitudes of desired wave components for individual delayed waves, performs weighting of the respective delayed wave components from detectors by using the estimated amplitudes, and makes symbol decision in terms of the combined weighted signal.
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: July 29, 1997
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Fumiyuki Adachi, Mamoru Sawahashi, Akihiro Higashi, Koji Ohno, Tomohiro Dohi
  • Patent number: 5596516
    Abstract: A code sequence generator having a register for holding n-bit code, and a calculation circuit for performing matrix calculation on the content of the register, and sequentially generating a code sequence by feeding back the calculation results to the register. The matrix which is set in the calculation circuit is changed by selectively reading a matrix from a memory circuit that stores precalculated matrices. This makes it possible to set a desired register state in a short time even if the desired code sequence is very long, and to generate any code sequences without changing the rate of a clock signal.
    Type: Grant
    Filed: April 25, 1995
    Date of Patent: January 21, 1997
    Assignee: NTT Mobile Communications Network Inc.
    Inventors: Akihiro Higashi, Koji Ohno, Narumi Umeda
  • Patent number: 5500856
    Abstract: A base station of a CDMA communication system includes a transmission de-correlator for eliminating interferences between communication channels of a downlink. The transmission de-correlator has a memory storing a set of data representative of the products of transmission information bits for the respective channels, and the sums of the products of the spread code data sequences for the respective channels, and the elements of an inverse matrix with respect to a predetermined matrix of a cross-correlation between the spread code data sequences for the respective channels. The sums correspond to additions of the products along a direction of columns or to additions of the products along a direction of rows of the inverse matrix. A counting device is operative for causing the memory to sequentially output the data therefrom. An adder serves to calculate a sum of the data outputted from the memory.
    Type: Grant
    Filed: July 28, 1994
    Date of Patent: March 19, 1996
    Assignees: Matsushita Communication Industrial Co., Ltd., NTT Mobile Communications Network, Inc.
    Inventors: Taku Nagase, Roland Go, Tadashi Matsumoto, Akihiro Higashi
  • Patent number: 5420850
    Abstract: A received signal of a control channel of each cell is despread by each spreading code in a correlation detector. The received level of the despread output in a window, including its peak, is measured in a level measuring part and an interference signal level outside the window is also measured. In a control part the difference or ratio between the measured received level and the interference signal level is obtained as a comparison signal for each spreading code, and the comparison signal is compared in terms of magnitude to thereby determine the visited cell of a mobile station.
    Type: Grant
    Filed: March 1, 1994
    Date of Patent: May 30, 1995
    Assignee: NTT Mobile Communications Network, Inc.
    Inventors: Narumi Umeda, Toyota Nishi, Akihiro Higashi
  • Patent number: 4925388
    Abstract: An apparatus for heat treating and quickly cooling substrates. The apparatus includes a cylindrical furnace core tube for containing substrates, a heater enclosing the furnace core tube, and outer cylinder enclosing and containing the furnace core tube and the heater, a blower for drafting cooling air to the space between the furnace core tube and the outer cylinder along the longitudinal direction of the furnace core tube, and a switching valve connected between the blower and both ends of the outer cylinder for switching the direction in which the cooling air travels. Since the direction of the cooling air is changed, the entire furnace core tube is uniformly cooled.
    Type: Grant
    Filed: September 22, 1989
    Date of Patent: May 15, 1990
    Assignee: Dainippon Screen Mfg. Co., Ltd.
    Inventors: Izuru Iseki, Akihiro Higashi, Seihiro Sasaki
  • Patent number: D414560
    Type: Grant
    Filed: October 8, 1998
    Date of Patent: September 28, 1999
    Assignee: Kabushiki Kaisha Fuji Iryoki
    Inventors: Akihiro Higashi, Takeshi Nishimura