Kokusai Denshin Denwa Co., Ltd.

Kddi Corporation

Kokusai Denshin Denwa Kabushiki Kaisha

Kdd Corporation

Other

Ddi Corp.

Nippon Hoso' Kyokai

Yoshio Takeuchi

Toshinori Suzuki

Akira Yamaguchi

Fumio Watanabe

Sumaru Niida

Toshio Mizuno

Naruhito Nakahara

Joichi Saito

Yuuji Ishida

Masayoshi Ohashi

Naoki Tsubaki

Seiichiro Sakai

Hideo Kobayashi

Yutaka Tanaka

Shoichi Suzuki

Hiroyasu Ishikawa

Takashi Inoue

Yoshinori Izumi

Seiichi Gohshi

Yoshiaki Amano

Taiichiro Kurita

Taiji Nishizawa

Junji Kumada

Kazuhiko Shibuya

Kazumasa Enami

Isao Kondo

Makoto Okui

Yasuaki Kanatsugu

Fumio Takahata

Minoru Honda

Ryoichi Yajima

Haruo Okuda

Mitsuo Nohara

Hisakazu Kato

Hisato Iwai

Teruhiko Honda

Ichiro Yuyama

Makoto Tadenuma

Hiroyuki Hamazumi

Sumio Yano

Yoshihiko Ito

A method of transmitting adaptive modulation signals using space-time block code matrix from a plurality of antennas, the method comprising the steps of: changing adaptively the number of transmission repeat times of the matrix according to a propagation condition, transforming modulation signals at each transmission repeat timing from each antenna by using the matrix, and sending the transformed signals at each transmission repeat timing from each antenna.

Method and apparatus for adaptive modulation using space-time block code matrix

A multi-beam cellular base station is for sending a spread spectrum signal to at least one mobile station, the base station comprising: first antenna for sending a common channel by a common beam that a directional pattern is formed previously; second antenna for sending a dedicated channel by a dedicated beam that a directional pattern is formed for each mobile station; and switching means for switching a sending time section of the common beam and a sending time section of the dedicated beam so that the sending time sections do not overlap within a time slot, the common beam and the dedicated beam are sent by same frequency.

Multi-beam cellular base station, mobile station and method for sending spread spectrum signal

A wireless packet communication system and a base station using an algorithm modified from an existing Proportional Fairness algorithm enables a control according to flexible adjustment of a throughput difference between mobile units and a priority between mobile units. A function for controlling a difference in throughput and a function for controlling a difference in throughput by the class by classifying a mobile unit are added to the conventional Proportional Fairness algorithm, thereby enabling flexible operation which is suitable for actual operation.

Wireless packet communication system and base station

In a mobile communication system having a plurality of radio packet channels of different transmission rate with each other between a base station and a mobile station, undesirable interference to adjacent cells of adjacent base stations is decreased. Signal quality of a receive signal at a mobile station is measured, and the better said signal quality is, the higher packet channel is assigned. Thus, although signal quality is poor because of long distance between a base station and a mobile station, no increase of transmission power of a base station is requested. Thus, interference to adjacent cells is decreased. When high rate packet channel is selected, short packet transmission time may be assigned so that amount of data transmission is kept uniform in spite of said signal quality.

Mobile communication system having adaptively assigned packet rate

A base station apparatus, a mobile radio system, and a transmission power control method that can perform transmission power control having the high interference suppressing effect with a smaller processing delay are provided. The base station apparatus comprises: a measurement part for measuring SIRs of a received signal subjected to interference suppression by an interference suppressing receiving circuit in a former stage in an interference suppressing receiving part of the radio base station apparatus, and of a received signal subjected to interference suppression by an interference suppressing receiving circuit in a later stage; a calculation part for calculating a correction SIR based on the obtained SIRs, and for estimating a transmission power control SIR from a current first stage SIR and a past correction SIR; and a signal generator for generating a transmission power control signal by comparing the transmission power control SIR and a target SIR. Control of transmission power of a mobile station is performed by transmitting this transmission power control signal to the mobile station.

Base station apparatus, mobile communication system, and method of controlling transmission power

This invention provides a spread spectrum signal demodulator in which a noise component included in respective demodulation symbols is reduced and an effect of interference removal is further improved. Symbol decorrelating means detect correlations between spread codes allocated to spread spectrum signals to be removed and a receiving signal. A symbol deciding means synthesizes one or the plurality of one symbol correlation values b1 to bk in common phase, namely, diversity-synthesizes them so as to decide a symbol. As the symbol decision, hard decision or soft decision can be used. Correlation modification means input the one symbol correlation values b1 to bk output from the symbol decorrelating means and the symbol decided result output from the symbol deciding means thereinto, and modify the symbol correlation values b1 to bk. The modified symbol correlation values d1 to dk are transmitted into interference replicating means so as to be spectrum-spread by corresponding spread codes.

Spread spectrum signal demodulator

A mobile communication system includes a plurality of antennas for sending and receiving beams, a plurality of mobile terminals moving in a fixed direction substantially, and a zone-shift control unit for treating the moving mobile terminals locating within a predetermined area as a single moving zone and for controlling the antennas and directions of the beams so that the beams always cover the moving zone.

Mobile communication system with zone-shift control apparatus

In order to prevent decrease of channel efficiency and to effectuate high quality communication while moderating increase of apparatus scale of an interference canceler part and cutting down costs, in a mobile communication and radio base station apparatus according to the present invention, an interference cancel processing part within the base station apparatus is provided with reverse spread processing/respread processing parts for performing reverse spread processing and respread processing on received signals, synthesizing processing parts for synthesizing signals that have been subjected to the respread processing, and subtraction processing parts for subtracting the synthesized signal from received signal, in multiple stages. The interference cancel processing part processes received signals of users &num;1-&num;k. As a demodulation processing part, there is provided n demodulation processing parts that perform demodulation processing for received signals of users &num;1-&num;n, the number of those users being larger than the number of the users that can be processed in the interference cancel processing part. Those demodulation processing parts perform demodulation processing with respect to signals that have been subjected to the interference cancel processing.

Mobile communications system and radio base station apparatus

A control method of transmitting power in a cellular system includes a step of measuring a signal to interference power ratio of a received signal at said receiving side, a step of detecting frame errors of the received signal at the receiving side, a step of counting the number of the detected frame errors n(k) (k and n(k) are positive integers and 1&lE;k&lE;K) for every M(k) (M(k) is a positive integer) frames, or for last N(k) (N(k) is a positive integer) frames just before the frame error is detected, a step of adjusting a value of a target SIR depending on one or set of the counted numbers of frame error n( ) to n(K), a step of comparing the measured SIR with the adjusted target SIR to provide a compared result, and a step of controlling at the transmitting side the transmitting power depending on the compared result.

Control method of transmitting power in cellular system

A mobile communication system includes a first and second systems. Each of the first and second systems has a land station and at least one mobile terminal capable of communicating with the land station. The land station of the first system has a broadcasting channel transmission unit for transmitting status information via a broadcasting channel, and the mobile terminal of the second system has a broadcasting channel receiving unit for receiving information in the broadcasting channel to obtain a broadcasting channel receiving condition and the status information, a giving interference estimation unit for estimating giving interference level onto communication of the first system by the second system based upon the obtained broadcasting channel receiving condition and the obtained status information, and an output signal level control unit for controlling output signal level of the mobile terminal of the second system based upon the estimated giving interference level.

Mobile communication system

Spread-spectrum signal demodulator

A calling location and a receiving location are analyzed by called party number analysis means by processing a called party number for specifying a communication terminal at the receiving side transmitted by a communication terminal at the calling side is processed, a charging unit price is determined by charging unit price determination means by referring to contents of a table memory storing a table of charging unit price using the calling location and the receiving location as parameters, and the information of charging unit price is informed to a communication terminal through a charging unit price determination/information apparatus, whereby a communication fee according to the receiving destination can be informed to the caller, or the receiver.

Charging unit price determination/information apparatus and

An error control method for wireless data transmission over a digital mobile communication system includes a step of obtaining, during data communication, statistical information including transmission error information at a receiving side, a step of determining an error control strategy and/or a value of at least one parameter of the error control strategy which are/is optimum for transmission path conditions at that time, based upon the obtained statistical information, and a step of using the determined error control strategy and/or the at least one parameter for the error control during data communication.

Error control method and apparatus for wireless data communication

A mobile communication system is disclosed which precludes the necessity for mobile station to perform processing for microcell zone switching even when it moves from one microcell zone to another and which permits high-speed microcell zone handover. The service area of mobile communication is split into a plurality of macrocells; the macrocells are each subdivided into a plurality of microcells; a microcell base station equipped with a transmitting and receiving antenna and a power amplifier is installed in each microcell; a different communication channel is assigned to individual mobile station in the macrocell; even when the mobile station moves from one microcell to another, no channel handover takes place; and only when the mobile station moves from one macrocell to another, a mobile network control center which supervises the macrocell base stations effects channel handover.

Macrocell-microcell communication system with minimal mobile channel

In the preliminary authentication stage, the mobile station (35) is authenticated by sending from the home network (30) to the roamed network (31), a plurality of pairs of first random numbers (RNDa.sub.1, . . . , RNDa.sub.n) and calculation results (SRESa.sub.1, . . . , SRESa.sub.n) of the cipher function (f), which calculation is performed at the home network using the secret key (ki) and the first random numbers (RNDa.sub.1, . . . , RND.sub.an), by sending, from the roamed network to the mobile station, third random numbers formed by coupling second random numbers (RNDb.sub.1, . . . , RNDb.sub.m) produced at the roamed network with the first random numbers (RNDa.sub.1, . . . , RNDan), by sending, from the mobile station to the roamed network, calculation results (SRESa.sub.1, . . . , SRESa.sub.n, SRESb.sub.1, . . . , SRESb.sub.m)) of the cipher function (f), which calculation is performed at the mobile station using the secret key (ki) and the sent third random numbers, and by confirming, at the roamed network, coincidence of the calculation results (SRESa.sub.1, . . . , SRESa.sub.n) sent from the mobile station with the calculation results (SRESa.sub.1, . . . , SRESa.sub.n) sent from the home network. In the main authentication, the mobile station is authenticated by using a pair of the second random number (RNDb.sub.1, . . . , RNDb.sub.m) and of the calculation result (SRESb.sub.1, . . . , SRESb.sub.m) with respect to the second random number (RNDb.sub.1, . . . , RNDb.sub.m), sent from the mobile station.

Authentication method for mobile communications

Growing community of inventors

Saitama, Japan

Yoshio Takeuchi