Ntt Docomo, Inc.

Ntt Mobile Communications Network, Inc.

Nippon Telegraph and Telephone Corporation

Yoshihiro Ishikawa

Fumiyuki Adachi

Yukihiko Okumura

Seizo Onoe

Masafumi Usuda

Hidehiro Ando

Satoshi Suyama

Jiyun Shen

Yusuke Ohwatari

Yousuke Sano

Takahiro Asai

Kazuaki Takeda

Nobuhiko Miki

Shohei Yoshioka

Mamoru Sawahashi

Anass Benjebbour

Akira Yamada

Satoshi Nagata

Hideaki Takahashi

Hiroki Harada

Yoshihisa Kishiyama

Mikio Iwamura

Hiroyuki Miyazaki

Toshio Miki

Tomoyuki Ohya

Shinji Uebayashi

Akihiro Higashi

Hiroyuki Ishii

Yasushi Takatori

Masato Mizoguchi

Hirantha Abeysekera

Riichi Kudo

Yuki Inoue

Yuta Sagae

Hiromasa Fujii

Hirohito Suda

Tatsuki Okuyama

Tatsunori Obara

Jun Mashino

Akihito Morimoto

Yasufumi Morioka

Shinsuke Ogawa

Etsuhiro Okamoto

Koji Ohno

Yoshifumi Morihiro

Yousuke Iizuka

Tetsuro Kitayama

Takahiro Kubo

Tomohiro Dohi

Masato Maeda

Hidetoshi Ebara

Koichi Okawa

Yoshinori Miki

Syunsuke Seo

Junichiro Hagiwara

Takeo Ichikawa

Akira Kishida

Takehiro Ida

Shigeru Tomisato

Masashige Shirakabe

Tetsuro Imai

Hiroto Yasuda

Mitsuo Iwanaga

Jaturong Sangiamwong

Masayuki Furusawa

Nobuhide Nonaka

Hidekazu Murata

Hiroo Omori

Masaharu Hata

Naoki Uehara

Hirantha Sithira Abeysekera

Yuuta Takahashi

Yousuke Izuka

Akihiro Hayashi-Syataku 3-301 Higashi

Koji Tomioka-Syataku 8-502 Ohno

Deterioration in communication characteristics is prevented by performing scheduling in which movement/stillness of user terminals is taken into consideration. Received-power measurement sectionmeasures the power of a reference signal from each of the user terminals. Movement/stillness determination sectiondetermines whether each of the user terminals is a moving terminal or an unmoving terminal based on over-time variations in received power at transmission points for each of the user terminals. Group selection sectiongroups the user terminals into a moving terminal group and an unmoving terminal group, and selects one of the groups as a signal-transmission target. Transmission control sectionperforms open-loop signal processing without precoding when the moving terminal group is selected, or performs closed-loop signal processing with precoding when the unmoving terminal group is selected.

Base station and transmission method

This base station comprises: a control unit that allocates, on the basis of a doppler shift estimated using an uplink reference signal, a downlink reference signal common to a plurality of beams; and a transmission unit that transmits the common downlink reference signal via the plurality of beams. According to this base station communication method, the base station allocates, on the basis of a doppler shift estimated using an uplink reference signal, a downlink reference signal common to a plurality of beams, and transmits the common downlink reference signal via the plurality of beams.

Base station and base station communication method

A radio terminal that performs radio communication with a radio base station including a plurality of transmission points each including at least one antenna element and a signal processing unit connected to the plurality of transmission points includes a plurality of antenna elements, an estimating section that estimates path-loss between each of the plurality of antenna elements and the plurality of transmission points, and a calculating section that calculates a power control weight for controlling transmission power of the plurality of antenna elements based on the path-loss for the antenna element that has been estimated by the estimating section.

Wireless terminal, transmission power control method, and wireless base station

Radio base stationin a radio communication system that performs MIMO transmission between a plurality of radio base stations and at least one user terminalincludes: precoding sectionthat applies precoding to data signals based on channel information indicating channels between radio base stationsand the user terminal; and communication sectionthat transmits the precoded data signals, in which the precoding in a first radio base station of the plurality of radio base stations is applied based on the channel information including at least a channel between the first radio base station and a first user terminal connected to a second radio base station other than the first radio base station.

Wireless base station and wireless communication method

A radio base station includes: an obtaining section that obtains a first communication quality of each of first communication terminals and obtains a second communication quality of each of second communication terminals having a lower communication speed than the first communication terminals; and a scheduler that schedules the first communication terminals based on the first communication qualities and schedules the second communication terminals based on the second communication qualities, and when the scheduler schedules the first communication terminals and the second communication terminals, the scheduler subjects the first communication terminals to space-division multiplexing and subjects the second communication terminals to frequency-division multiplexing or time-division multiplexing.

Wireless base station and scheduling method

In user terminalof the present invention, connection-cell-selection controlling sectionmeasures reception quality of signals respectively transmitted from cells and received by antenna section, corrects the reception quality of each of the cells based on a positional relationship between each of the cells and user terminaland based on a moving direction of user terminal, and determines a connection cell for user terminal(base station in communication with user terminal) based on the corrected reception quality. This configuration lowers a cell switching frequency, while preventing degradation of throughput and the like in a future radio communication system (multilayer cellular radio network).

User terminal and cell selection method

In a radio base station including: a plurality of transmission points each including at least one antenna element; and a signal processing unit connected to the plurality of transmission points, the signal processing unit includes: an estimating section that estimates, in each of the antenna elements, a path-loss with a radio terminal; and a calculating section that calculates a power control weight for controlling transmission power of each of the antenna elements based on the path-loss of the antenna element, which is estimated by the estimating section.

Wireless base station and transmission power control method

A wireless user equipment performing wireless communication in a primary and a secondary frequency bands, a first wireless access point AP performing the wireless communication in the primary frequency band, and a second wireless base transceiver station BTS performing the wireless communication in the secondary frequency band are included. The AP and the BTS are connected to each other through a network. A UD report transfer unit transfers a UD report including information relating to transmission-waiting user data destined for a receiving node. The receiving node includes a transmission opportunity control unit which sets a fixed transmission prohibition time in a channel in the primary frequency band for a wireless communication device in a vicinity, obtains a transmission opportunity, grants the transmission opportunity to the transmitting node, and causes the user data to be transmitted from the transmitting node according to the transferred UD report.

Wireless communication system and wireless communication method

User terminalconfigured to perform MIMO transmission with radio base stationincludes: control sectionconfigured to generate first channel estimation information based on a reference signal transmitted by radio base station, and perform an operation for elimination of an interference signal on the first channel estimation information to generate second channel estimation information; and postcoderconfigured to perform postcoding, based on the second channel estimation information, on a data signal to be transmitted by the radio base station, so as to detect a desired signal.

User terminal, wireless base station, and wireless communication method

Radio base stationconfigured to perform MIMO transmission with user terminalsincludes: beam selecting sectionconfigured to select at least one used beam from among a plurality of beams based on beam-selection reference parameters to be computed based on beam information transmitted by user terminals; and user terminal selecting sectionconfigured to select, from among at least one of user terminalswhich has selected the at least one used beam, at least one of user terminalsto be a target for the at least one used beam.

Wireless base station, and wireless communication method

A user apparatus, in a radio communication system including a plurality of base stations, including a reception unit configured to receive, from a connecting base station, control information to be used for reducing an interference signal sent from an interference base station for the user apparatus; and an interference reducing unit configured to reduce the interference signal by using the control information to obtain a desired signal sent from the connecting base station.

User apparatus, base station, interference reducing method and interference reducing control information notification method

A transmission and reception apparatus includes a plurality of antenna ports. The transmission and reception apparatus includes at least one orthogonal beam fixed beamforming circuit and a high-speed switching circuit between a transmission and reception circuit and the antenna ports. For example, the transmission and reception circuit outputs a transmission signal subjected to transmission signal processing to the high-speed switching circuit during signal transmission, the high-speed switching circuit selects at least one port from a plurality of ports provided at the orthogonal beamforming circuit, and outputs the transmission signal to the selected port, and the orthogonal beamforming circuit forms a beam corresponding to the selected port to transmit the transmission signal.

Transmission and reception apparatus

In a radio communication system that performs beamforming in MIMO transmission between a radio base station and at least one user terminal, radio base station () includes: weight control section () that determines a beamforming weight used for the beamforming, for each of subbands formed by dividing a transmission band; and communication section () that transmits a signal to which the beamforming is applied using the beamforming weight.

A radio communication device includes: a full-digital array that has a first antenna element group including multiple antenna elements and that has no analog variable phase shifter; and a hybrid beamformer that has a second antenna element group including multiple antenna elements and that has an analog variable phase shifter.

Radio communication device

In user terminal, communication sectionreceives a data signal to which precoding based on first channel information indicating a channel between radio base stationand user terminalestimated in first channel estimation and beamforming are applied. The first channel information is an equivalent channel matrix including a beamforming weight. Stage-2 channel estimation sectionperforms second channel estimation for estimating second channel information indicating a channel between radio base stationand user terminal. The second channel information is an equivalent channel matrix including the beamforming weight and a precoding matrix. Postcoding sectionperforms postcoding on the data signal based on the second channel information.

User terminal and wireless communication method

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Tokyo, Japan

Yukihiko Okumura