Nippon Telegraph and Telephone Corporation

Ntt Docomo, Inc.

Jun Mashino

Yukihiko Okumura

Satoshi Suyama

Takatoshi Sugiyama

Tatsuki Okuyama

Shohei Yoshioka

Hiroyuki Miyazaki

Kentaro Nishimori

Yusuke Asai

Kengo Nagata

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

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.

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

The receiving device receives a transmitted signal from a transmitting device by dividing by N the spectrum of a signal to be transmitted and performing spectrum editing to reduce its occupied bands. The receiving device generates a first decoded signal by error-correcting and decoding this received signal in the bandwidth of the signal to be transmitted, and generates a transmission replica signal from this first decoded signal and divides by N the spectrum of this transmission replica signal to generate N sub-replicas. The receiving device generates a compensated received signal by restoring the spectrum of the signal to be transmitted from the transmitting device using the N sub-replicas and the received signal, and decodes this compensated received signal to generate a second decoded signal.

Wireless communication system, transmitting device, receiving device, and wireless communication method

In a communication system configured by a transmitting station device and a receiving station device for transmitting and receiving a multicarrier signal using a spectrum including a plurality of subcarriers, a superposed rate which is a rate in which a superposed band in which interference is occurring is used in a used frequency band used for transmitting the multicarrier signal is set so as to increase frequency utilization efficiency of the used frequency band, and the multicarrier signal is transmitted using a spectrum allocated in accordance with the set superposed rate.

Control station device, transmitting station device, communication method, and communication system

A communication system employs a transmitting device and a receiving device. The transmitting device allocates certain data, based on transmission data, to both a non-superposed band, corresponding to a frequency band with no interference signal present, and a superposed band, corresponding to a frequency band where an interference signal is present. Alternatively, the transmitting device allocates the data to the non-superposed band while giving a higher priority to the non-superposed band. The transmitting device then generates and transmits a multicarrier signal based on the allocation, so that the receiving device can receive it.

Communication system, transmitting device, receiving device, transmission method, and communication method

In a wireless communication system including a transmitter device and a receiver device used for transmission of wireless signals having a plurality of sub-carriers, the transmitter device performs error correction coding on transmitting data and selects at least one of the plurality of sub-carriers used for transmission of error-correction coded data as a null sub-carrier having zero amplitude, thus transmitting the error-correction coded data, while the receiver device receives signals having the plurality of sub-carriers from the transmitter device so as to retrieve original transmitted data by implementing error correction decoding on received signals, thus determining whether an interference wave occurs in the sub-carrier upon detecting reception power exceeding a predetermined threshold in the sub-carrier serving as the null sub-carrier.

Wireless communication system and wireless communication method

It is possible to reduce the effect of an interference signal while suppressing increases in a circuit scale and a processing time. A reception device receives a multicarrier signal and an interference signal via a radio transmission path, detects a frequency position of the interference signal, performs filtering to suppress the multicarrier signal and the interference signal at the detected frequency position of the interference signal, removes a guard interval from the multicarrier signal suppressed by the filtering, demodulates each subcarrier of the multicarrier signal from which the guard interval is removed, and performs error correction on the demodulated signal.

Reception device and reception method

A directivity control system includes a first reception station device which receives an interference signal and a desired signal; a cooperative station device disposed at a different place from the first reception station device, which receives a signal using an antenna; and a control device which controls the directivity of an antenna of the first reception station device, wherein the control device regards a combination of the antenna of the first reception station device and the antenna of the cooperative station device as one array antenna, and calculates a sum, using a weight, of a received signal received using the antenna of the first reception station device and a received signal received using the antenna of the cooperative station device to compose a directivity pattern having a null in an arrival direction of the interference signal in the array antenna.

Directivity control system, control device, cooperative station device, reception station device, and method of controlling directivity

In a multicarrier wireless communication system adopting forward error correction codes, a reception method adapted to a receiverreceiving wireless signals is constituted of an interference band detection process for selecting a sub-carrier having low reliability among a plurality of sub-carriers of desired waves as a specific sub-carrier, a weight coefficient generation process for generating weight coefficients for reducing reliability in sub-carriers with respect to the selected specific sub-carrier, a demodulation process for demodulating received wireless signals of sub-carriers, a weighted calculation process for performing weighted calculation applying weight coefficients to demodulated values of sub-carriers of wireless signals, and a decoding process for performing a decoding process for error correction on values calculated of sub-carriers.

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Tokyo, Japan

Jun Mashino