Hitachi, Ltd.

Other

Kddi Corporation

Matsushita Electric Industrial Co., Ltd.

Nippon Telegraph and Telephone Public Corporation

Hitachi Denshi Kabushiki Kaisha

Hitachi Communication Systems, Inc.

Hiatchi, Ltd.

Nec Corporation

Toshiro Suzuki

Takashi Yano

Hiroshi Takatori

Takanori Miyamoto

Kazuhiro Kondo

Nobukazu Doi

Takashi Inoue

Takaki Uta

Sumaru Niida

Mikio Kuwahara

Tohru Kazawa

Eiichi Amada

Takashi Morita

Yuji Ishida

Takeshi Maki

Masataka Ohta

Mikiya Namura

Kenichi Aoyama

Yuji Fukai

Masaru Kokubo

Katsuhiko Tsunehara

Akira Ichikawa

Hirotoshi Shirasu

Yoshiaki Asakawa

Yasuo Kogure

Tatsuya Kameyama

Izumi Horikawa

Yuuji Ishida

Takafumi Kojima

Hirotaka Hara

Osamu Matsubara

Ryujiro Muramatsu

Izuru Yamada

Masashi Tamakoshi

Takao Harakawa

Satoshi Takahashi

Ken Takei

Hiroshi Kuwahara

Satoshi Masuda

Toshinori Suzuki

Yoshitaka Takasaki

Masashi Yano

Arata Nakagoshi

Tetsuhiko Hirata

Keiji Tomooka

Norihisa Matsumoto

Joichi Saito

Kazuhito Ishida

Osamu Yumoto

Shoji Fukuzawa

Fumiaki Fujii

Motohiro Kokumai

Takakuni Kuki

Ayumu Koide

Hisato Iwai

Hiroshi Usami

Ichiro Masse

Tatsuto Okamoto

Yuichi Morikawa

Mutsumi Abe

Akio Yasuda

Douglas Cardwell

Tsuyoshi Taniguchi

Yoshinori Kuroki

Sotaro Hiroshima

Ichiro Mass'e

Koichi Shimizu

Nobuo Kunimi

Hirohiko Sato

Souichi Yamashima

Haruo Kamimaki

A radio base station apparatus provided with an array antenna having a plurality of antenna elements for calibrating a phase difference among the array antenna elements. The base station has a probe signal adding unit which divides one probe signal and adds the divided probe signals to each receive signals received by the plurality of antenna elements. A probe data extracting unit extracts the probe data from the receive signals added with the probe signal. A phase calibration calculation unit calculates correlating phase calibration values required for calibrating a phase of each receive signal based on the probe data extracted by the probe signal extracting unit. A phase calibration unit calibrates a phase difference among the array antenna elements by calibrating the phase of the each receive signal based on the phase calibration from the phase calibration calculation unit.

Antenna unit and radio base station therewith

Phase and amplitude deviations, which are generated, for example, by cables connecting an array antenna of a CDMA base station and the base station, are calibrated in the baseband. The base station comprises: an antenna apparatus; couplers; an RF unitthat converts a receive signal to a baseband signal, converts a transmit signal to a radio frequency, and performs power control; an A/D converterfor converting a receive signal to a digital signal; a receive beam form unitthat multiplies the receive signal by semi-fixed weight; a despreaderfor this signal input; a time-space demodulatorfor demodulating user data; a despreaderfor probe signal; a space modulatorfor user data; a spreaderfor user signal; a channel combiner; a Tx calibraterfor controlling calibration of a signal; a D/A converter; a unitfor calculation of correlation matrix for generating a probe signal used for controlling an Rx calibration system and a TX calibration system; a spreaderfor probe signal; a power control unit; a D/A converter; an RF unitfor probe signal; an A/D converterfor signal from the couplers; and a despreader

In a mobile communication system employing code division multiple accesses and having radio logical channels such as control channels and traffic channels, for the purpose of interference cancellation processing which is implemented without a large processing delay even under a call control application, the baseband receiving part of the mobile communication system includes a common control channel demodulatorwhich executes the demodulation processing of a common control channel as to a received baseband reception signal, an interference cancellerwhich executes interference cancellation processing for a received multiplexed signal on the basis of the notification information of the control channels, and a synthesis/error correction processorwhich executes error correction processing, etc. as to user information having undergone the interference cancellation processing and thereafter executes frame formation processing. The common control channel is demodulated by the common control channel demodulatorand is not submitted to interference cancellation processing, thereby to heighten the processing speed of system information. In the interference canceller, cross-correlation interferences are cancelled as to the dedicated control channel and the traffic channel other than the common control channel, thereby to enhance a channel efficiency.

Base station and mobile communication system

In a mobile communication system, the tracking of synchronization is conducted in a stable state even in a multipath environment. A delay profile detector calculates a delay profile a(n) using a despread signal for each processing unit n. A delay profile averaging unit averages a(n) to produce Ave(|a(n)|). A data symbol detector conducts rake combining of the despread signal using a(n) and Ave(|a(n)|). According to a(n) and Ave(|a(n)|, a weighting function unit calculates a representative value representing delay waves. A loop filter generates a control signal in response to the representative value. A clock controller controls a spread code generator according to the control signal.

Mobile terminal, a base station, and a synchronization control method

On the side of a mobile station, interference of a perch channel with call control information or a traffic channel is reduced, realizing stable communication. In a method of CDMA communication in which communication is made through the traffic channel for transmitting user data and the perch channel for transmitting a spreading code used for demodulation of the user data, the traffic channel has a call control channel subjected to the time division multiplex, and that call control channel and a part of the perch channel, which is non-orthogonal to the call control channel, are arranged not to overlap with each other in a time base.

Mobile communication method using CDMA multiplexing technique and mobile communication system

The present invention provides a transmit power controlling method for reducing an influence of incorrect control in a mobile communication system in the CDMA mode. A likelihood of transmit power controlling signal is generated on the basis of the transmit power controlling signal transmitted by a radio base station and the receiving quality, a variation amount of the transmit power is generated on the basis of the likelihood, and the transmit power of a mobile station is controlled on the basis of the variation amount.

Method for controlling transmit power for communication system

In a time-division multiplexing wireless communication system, an antenna module has plural antenna elements. Receiver high-frequency circuit synthesizes signals from the antenna elements according to an antenna directivity having a desired beam pattern. Demodulator selects one of the received signals from wireless terminals according to the synthesized received signals, and determines transmission beam direction information for use in directing the beam in the selected direction. Weighting circuit generates weight coefficients for setting of the beam patterns and transmission beam directions according to the transmission beam direction information, and produces transmission time slots according to a table listing the relations of the transmission beam directions and the time slots for use in the beam radiation in those directions. Down-link fixed beam-forming circuit and modulator control the antenna module using the generated beam pattern, beam direction and transmission time slots to transmit the down-link signal.

Wireless communication method and system using beam direction-variable antenna

A mobile communication system which includes an exchange, a plurality of base stations, and a plurality of radio telephone sets communicatable with the associated base stations. In order to suppress or reduce call loss caused by traffic congestion or by faulty one of the base stations, an uncommunicatable service area of the faulty base station is covered by the other working base stations. The exchange detects operation states of all the base stations, searches a base-station state pattern table within the exchange for base-station control data suitable for the operation states to read out the base-station control pattern, and transmits the read-out base-station control data to the base stations to cause radio service areas of the base stations to be set to have desired radiation patterns according to the read-out base-station control data.

Integrated control system for radio service areas of base stations in mobile communication system

Disclosed is a control apparatus capable of more effectively utilizing radio resources. Mobile stations positioned close to each other are treated as one group, and a direction and width (radiation angle) of a beam radiated from an adaptive array antenna is controlled for each group so that one beam capture one group. To be concrete, a plurality of mobile stations are classified into groups by a classification section , and an area to which each group moves is estimated by a directivity determination section . The adaptive array antenna is controlled by the directivity control section so that one beam can cover an area in which one group is positioned and the area to which this one group moves.

Method of controlling directional antenna and apparatus of the same

In a mobile communication system, the tracking of synchronization is conducted in a stable state even in a multipath environment. A delay profile detector calculates a delay profile a(n) using a despread signal for each processing unit n. A delay profile averaging unit averages a(n) to produce Ave(&verbar;a(n)&verbar; ). A data symbol detector conducts rake combining of the despread signal using a(n) and Ave(&verbar;a(n)&verbar; ). According to a(n) and Ave(&verbar;a(n)&verbar; , a weighting function unit calculates a representative value representing delay waves. A loop filter generates a control signal in response to the representative value. A clock controller controls a spread code generator according to the control signal.

A mobile communication system that can obtain mobile station location information repeatedly at short intervals, without depending on whether base stations are synchronous or asynchronous, with lower loads and suppressed use of radio resources. For obtaining location information, a mobile station receives a paging channel periodically sent from a base station (Step ), obtains the contents and the reception timing of this paging channel. Further, if it is necessary to obtain the transmission timing of the paging channel, that transmission timing is obtained (Steps ). The propagation delay of the paging channel or propagation delay differences between a plurality of periodic paging channels are calculated from the transmission timing and the reception timing of the paging channel (Step ). The mobile station location information is calculated from the propagation delay or propagation delay difference, and outputted (Steps ).

Mobile communication system, mobile station, and base station that calculates distance from mobile station

A mobile radio communications system having a plurality of base stations accommodating a plurality of mobile stations through radio transmission channels, each of the base stations being connected to a mobile communications exchanger through a plurality of signal lines. Each of the base stations is provided therein with a signal line allocating function unit for selecting a particular signal line from a plurality of signal lines and for allocating a communication slot for a mobile station dominated by the base station at a particular slot position on the selected signal line, a radio channel allocating function unit for allocating a communication slot for the mobile station dominated by the base station at a particular slot position on a radio transmission channel at a particular frequency, and a radio signal delay control unit for performing delay control for a timing at which the base station transmits a radio signal to the mobile station dominated by the base station.

Mobile radio communications system

Growing community of inventors

Tama, Japan

Toshiro Suzuki