Hitachi, Ltd.

Fipa Frohwitter Intellectual Property Ag

Hitachi Denshi Kabushiki Kaisha

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Hitachi Communication Technologies, Ltd.

Hitachi Video Engineering, Incorporated

Hitachi Medical Corporation

Kddi Corporation

Hitachi Video Eng. Inc.

N.v. Philips' Gloeilampenfabrieken

Htachi, Ltd.

Fipa Frohwitter International Property Ag

Nobukazu Doi

Takashi Yano

Mikio Kuwahara

Katsuhiko Tsunehara

Seiichi Mita

Morishi Izumita

Yasuo Ohgoshi

Tomoaki Ishifuji

Riaz Esmailzadeh

Takaki Uta

May Suzuki

Hironari Masui

Masayuki Ariyoshi

Toshiro Suzuki

Yoshito Ohta

Tesshin Shiga

Yoshizumi Eto

Seishi Hanaoka

Masaaki Shida

Hideya Suzuki

Takashi Inoue

Atsushi Ogino

Yuji Ishida

Hiroto Yamauchi

Sumaru Niida

Mamoru Kaneko

Keiji Hasegawa

Tsuyoshi Tamaki

Manabu Kawabe

Ryota Yamasaki

Akira Saito

Morito Rokuda

Ayumu Koide

Kazuko Hamaguchi

Tetsuya Amano

Yoshinori Okada

Hiroshi Ide

Shusaku Nagahara

Johannes W Bergmans

Masuo Umemoto

Nobuo Murata

Shigeyuki Ikeda

Tohru Setoyama

Hideki Imai

Yusuke Uchida

Yuichi Michikawa

Junko Nakase

Kazuyuki Takeshita

Yasuo Inagaki

Hitoshi Katayama

Susumu Kasai

Hiroyuki Hanyu

Raiz Esmailzadeh

Hitoshi Takagi

Hiroshi Shiono

Fuyuki Inui

Shigeaki Fujino

In a mobile communication system using a code division multiple access (CDMA) method, spreading code detection and frame/slot timing synchronization (cell search) is conducted by using a long code masked symbol. The spreading factor of the long code masked symbol is set to a value lower than spreading factors of other ordinary symbols. As a result, it becomes possible to reduce the circuit scale and power dissipation of the mobile terminal and raise the speed of cell search.

Code division multiple access mobile communication system

A radio communication system having a base station and a plurality of radio terminals, wherein each radio terminal having a transmission request transmits a reservation packet at arbitrary timing through a reservation channel in accordance with a CDMA scheme, and the base station assigns a traffic channel and a time slot to be used to each radio terminal requesting a reservation through a reply packet outputted onto a reply channel. On the reservation channel, a short spreading code corresponding to a matched filter is applied.

CDMA mobile communication system and communication method

In a spread spectrum communication system, one (W.sub.n) of a series of orthogonal codes for spectrum spreading is assigned to signal-to-noise ratio measurement in a terminal. On the basis of a noise signal detected by de-spreading a signal received from an antenna with the above described orthogonal code (W.sub.n) and a pilot signal, each terminal derives a signal-to-noise ratio. Each terminal transmits the signal-to-noise ratio to the base station as a power control signal. On the basis of signal-to-noise information received from each terminal as the power control signal, the base station controls signal transmission power for each terminal.

Spread spectrum communication system and transmission power control method therefor

Particular orthogonal codes are transmitted from the mobile stations to the base station as alert signals indicating the presence of data to be transmitted. The base station checks whether particular orthogonal codes are contained in the alert signals, and when the particular orthogonal codes are detected in the alert signals, information representing the detected orthogonal codes and the schedules for transmitting the data from the mobile terminals to the base station are transmitted from the base station to the mobile terminals as an alert response to the alert signals. When the information representing the orthogonal codes used for the alert signals are contained in the alert response transmitted from the base station to the mobile terminals, the data waiting to be transmitted is transmitted from the mobile terminals to the base station according the data transmission schedules in the alert response.

Method of mobile communication and apparatus therefor

In order to accomplish efficient communication of data between a base station and a plurality of mobile terminals, particular orthogonal codes are transmitted from the mobile stations to the base station as alert signals indicating the presence of data to be transmitted. The base station checks whether particular orthogonal codes are contained in the alert signals, and when the particular orthogonal codes are detected in the alert signals, information representing the detected orthogonal codes and the schedules for transmitting the data from the mobile terminals to the base station are transmitted from the base station to the mobile terminals as an alert response to the alert signals. When the information representing the orthogonal codes used for the alert signals are contained in the alert response transmitted from the base station to the mobile terminals, the data waiting to be transmitted is transmitted from the mobile terminals to the base station according the data transmission schedules in the alert response.

By using the delay profile created by delay profile creating sectionand the first threshold valuereceived from the first threshold value calculation, the first threshold value timing detection sectionselects only the earliest receive timing exceeding the first threshold value, from all the timing that the correlation value in the delay profile becomes a maximum. By using the receive timing and the second threshold valuereceived from the second threshold value calculation section, reference timing calculation sectionselects the reference timing required for calculating the receive timing for the incoming wave of the minimum propagation delay time. The timing delayed by previously set timing behind said reference timing is sent from receive timing calculation sectionas the receive timingof the incoming wave of the minimum propagation delay time.

Method for measuring distance and position using spread spectrum signal, and an equipment using the method

In CDMA communications, a base station detects a difference between a reference phase of a spreading code and a phase of a received signal of each terminal station, and feeds a phase jump signal PJ-i representative of the phase difference back to each terminal station. After timing acquisition, the reception operation is performed using the reference phase, and a shift amount between the phase of a received signal and the reference phase is fed back to each terminal station as phase synchronization control information PC-i. Each terminal station coarsely adjusts the phase of the spreading code in accordance with the phase jump signal PJ-i, and thereafter finely adjusts the phase of its transmitting signal in accordance with the phase synchronization control information PC-i. It is therefore possible to synchronize the phases of the signals transmitted from terminal stations and received at the base station. Accordingly, an orthogonal code is used for spreading on the reverse links.

CDMA communication system and method

By using the delay profile created by delay profile creating sectionand the first threshold valuereceived from the first threshold value calculationthe first threshold value timing detection sectionselects only the earliest receive timing exceeding the first threshold value, from all the timing that the correlation value in the delay profile becomes a maximum. By using the receive timing and the second threshold valuereceived from the second threshold value calculation sectionreference timing calculation sectionselects the reference timing required for calculating the receive timing for the incoming wave of the minimum propagation delay time. The timing delayed by previously set timing behind said reference timing is sent from receive timing calculation sectionas the receive timingof the incoming wave of the minimum propagation delay time.

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

Growing community of inventors

Hachioji, Japan

Nobukazu Doi