Ntt Docomo, Inc.

Tokyo Institute of Technology

Sharp Kabushiki Kaisha Corporation

Other

Satoshi Suyama

Yukihiko Okumura

Tatsuki Okuyama

Jiyun Shen

Tatsunori Obara

Jun Mashino

Hiroshi Suzuki

Kazuhiko Fukawa

Takahiro Asai

Shohei Yoshioka

Ryota Yamada

Takashi Yoshimoto

Naoki Okamoto

Hitoshi Yoshino

Hiroyuki Miyazaki

Hui Shi

Nobuhide Nonaka

Minoru Kubota

Anass Benjebbour

Yuki Inoue

Hiromasa Fujii

Yusuke Ohwatari

Takahiro Kubo

Katsuya Kato

Takefumi Yamada

Yoshifumi Morihiro

Tetsuro Imai

Hidekazu Murata

Yuuta Takahashi

Hirosama Fujii

A control apparatus includes a control section that determines, for each terminal, a method for a coordinated operation performed between a plurality of radio apparatuses for signal transmission to the terminal, and a transmission section that outputs control information on the method determined.

Control apparatus, radio communication system, and control method

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 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

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 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

A management apparatus in a wireless communication system including multiple transmission points transmitting reference signals, the management apparatus managing the transmission points, and a mobile station, includes: a management unit for managing first and second clusters generated by grouping one or more transmission points used to communicate with the mobile station among the multiple transmission points; and a control unit for controlling allocation of the reference signals transmitted from the multiple transmission points in the first and second clusters. The management unit detects that multiple cells formed by the transmission points in the first cluster overlap some of multiple cells formed by the transmission points in the second cluster. When the management unit detects the overlap, the control unit allocates the orthogonal reference signals to the multiple cells formed by the transmission points in the first cluster and the multiple cells formed by the transmission points in the second cluster.

Management apparatus

A user equipment UE includes: a measurer that measures, for each of a plurality of candidate beams, a benchmark pertaining to communication quality; a comparer that compares the benchmark with a first threshold value and a second threshold value; and a feedback unit that transmits the benchmark to the base station as feedback information pertaining to an interference beam if the benchmark is the first threshold value or higher and lower than the second threshold value, transmits the benchmark to the base station as feedback information pertaining to a desired beam if the benchmark is the second threshold value or higher, and transmits no feedback information to the base station if the benchmark is lower than the first threshold value, based on the comparison results of the comparer.

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Tokyo, Japan

Satoshi Suyama