Ntt Docomo, Inc.

Nippon Telegraph and Telephone Corporation

Ntt Mobile Communications Network, Inc.

Hirohito Suda

Hiromasa Fujii

Shigeru Tomisato

Takahiro Asai

Takefumi Yamada

Tetsushi Abe

Jiyun Shen

Shinzo Ohkubo

Tetsu Tanaka

Satoshi Nagata

Lan Chen

Yasushi Yamao

Xiaoming She

Yu Jiang

Xiang Yun

Akira Shibutani

Jing Wang

Takehiro Moriya

Narumi Umeda

Yukihiko Okumura

Qun Zhao

Juejia Zhou

Toshio Miki

Toshiro Kawahara

Tomoyuki Ohya

Jianchi Zhu

Yongsheng Zhang

Hiroyuki Kawai

Atsushi Fujiwara

Kazunori Mano

Yuji Aburakawa

Masato Maeda

Tatsuo Furuno

Kohei Mizuno

Mitsuru Murata

Hitoshi Ohmuro

Masahiro Umehira

Kazunaga Ikeda

Hitoshi Hayashi

Masashi Shimizu

Kosei Takiishi

Tatsuro Masamura

Hirofumi Takagi

Satoshi Miki

Syuji Kubota

Shuichi Yoshino

Toshiaki Tanaka

Yihong Qi

Masayoshi Nakayama

Katsutoshi Nidaira

Eisuke Kudo

Akinori Shibuya

Eisuke Kudoh

Fujii Hiromasa

A base station receives channel state information corresponding to each of spare coordinated groups from each of user devices. A first group includes a plurality of coordinated groups arranged in advance. The spare coordinated groups corresponding to each user device are such as selected from the first group and include at least a service sector of best channel quality obtained measurement by the user device. The base station specifies a user device group corresponding to each of coordinated groups contained in each of coordinated group patterns. The user device group corresponding to the coordinated group is formed of user devices having the coordinated group in their spare coordinated groups. The base station uses channel state information reported from the user devices of the user device group corresponding to the coordinated group as a basis to perform user scheduling on the coordinated group.

Communication processing method and base station

In order to recognize a relatively accurate channel state of each UE, a channel of the UE is reconfigured based on channel phase information and channel quality information reported from the UE to obtain a channel matrix of the UE. Besides, a channel of the UE is reconfigured based on channel phase information and channel quality information reported from the UE to obtain a channel matrix of the UE, a precoding matrix of the UE is determined based on the channel matrix of the UE, and precoding is performed on data to transmit to the UE, using the precoding matrix.

Channel reconfiguration method, precoding method and apparatus therefor

Provided are a method for coordinating inter-cell interference in a heterogeneous network (HetNet) and the heterogeneous network. The method includes: forming M normal base stations and low-power nodes within coverage of the respective normal base stations in the heterogeneous network into a coordinated group; combining mute/non-mute states of bandwidths of the M normal base stations to obtain a plurality of states of the coordinated group; a user of each of the normal base stations feeding at least one first CQI back to the normal base station; a user of each of the low-power nodes feeding one or more second CQIs back to the low-power node; using the first CQI and the second CQIs as a basis to make capacity estimation of the coordinated group; and setting the mute/non-mute states of the bandwidths of the M normal base stations in accordance with a state of the coordinated group corresponding to an optimal system capacity so as to perform data transmission. In the method for coordinating interference provided by the present invention, M transmission points each including one or more normal base stations and low-power nodes covered by the respective normal base stations can be formed into a coordinated group, thereby extending processing for the normal base stations up to all the transmission points in the coordinated group.

Method for coordinating inter-cell interference in heterogeneous network and heterogeneous network

The present invention discloses a method and a device for discovering a UE, a first UE and a base station. The method for discovering a UE comprises the steps of: monitoring, by a first UE, an uplink signal in a mobile communication system; extracting, by the first UE, first information for identifying a UE that is to be discovered and that transmits the uplink signal from the monitored uplink signal; transmitting, by the first UE, a monitoring report message carrying the first information to a base station, acquiring, by the first UE, the device ID of the UE to be discovered in accordance with the monitoring report response message and completing the discovery process of the UE. According to the present invention, it is able to discover the UE without changing a channel system of an existing system and occupying time-frequency resources of the system.

Method and device for discovering UE, first UE and base station

A transmitter which transmits information in transmission frame to a receiver, the transmission frame including multiple transmission symbols and guard intervals obtained by replicating a fixed time period of a transmission symbol, generates a transmission frame by making phases of one transmission symbol out of two transmission symbols and a guard interval thereof continuous with phases of the other transmission symbol and a guard interval thereof, when the two continuous transmission symbols are the same.

Transmitter and method for configuring transmission frame

A receiver that receives a signal from a transmitter, including: a plurality of antennas; a channel estimation unit; a channel accumulation unit; a transmission weight generator; a feedback information transmission unit; and a reception weight generator. The plurality of antennas receive a second signal from the transmitter, the second signal being transmitted by using first feedback information. The channel estimation unit estimates a communication channel state on the basis of the second signal, and then outputs second channel estimation information. The reception weight generator generates reception weight information to be multiplied by the second signal, on the basis of first channel estimation information accumulated in the channel accumulation unit and a first transmission weight.

Multiple-output multiple-input (MIMO) communication system, MIMO receiver and MIMO receiving method

A wireless relay system for relaying a radio signal transmitted from a first wireless station to a second wireless station via a wireless relay apparatus is disclosed. The wireless relay system includes a relay control part for receiving transmission symbols transmitted from the first wireless station and refraining from relaying a portion of the symbols, a pilot signal transmission part for transmitting a pilot signal that is inserted into a section of the portion of the transmission symbols, a coupling loop interference wave estimation part for receiving the pilot signal and estimating a coupling loop interference wave based on the pilot signal, and a coupling loop interference wave cancellation part for subtracting the estimated coupling loop interference wave from a reception signal.

Wireless relay system, wireless relay apparatus, and wireless relay method

This invention provides an MIMO communication system and MIMO communication method. An MIMO receiver estimates state of each communication channel from the received signals received by #1 to #L antennas, generates feedback information according to the information of channel state, sends the feedback information to a transmitter through a feedback path, processes the feedback information in order to compensate feedback-delay of the feedback path, generate K*L proper reception weights by using the information of channel state and processed feedback information, multiplies the received #1 to #L substreams of respective #1 to #K signal streams by the proper #1 to #L reception weights, respectively, composes the #1 to #L weighted substreams to obtain respective composed #1 to #K signal streams and demodulate the composed #1 to #K signal streams, respectively, and combines the demodulated K signal streams to reproduce an original transmission signal.

A receiving station used in a wireless communication system receives information from one or more transmitting stations. The receiving station comprises a receiving unit () configured to receive information containing ID information of a transmitting station, and a data extracting unit () configured to extract the ID information from the received information. Transmit timing sequence acquiring means (and) of the receiving station estimates a transmit timing sequence (Hs) of the transmitting station based on the extracted ID information. Synchronizing means () of the receiving station brings the receive timing of the receiving station in synchronization with transmit timing of the transmitting station based on the transmit timing sequence.

Wireless communications system, transmitting station, and receiving station

Symbols converted by a serial-to-parallel converting part () from serial to parallel form are subjected to inverse Fourier transform processing in an inverse Fourier transform part () as sub-carrier signal components of a frequency interval equal to the symbol rate, then the levels of the resulting time domain signal components are compared with a permissible peak level Cin a peak component detecting part () to detect peak components, and the peak components are transformed by a Fourier transform part () to frequency domain components, which are subtracted by subtractors (to) from the corresponding sub-carrier signal components to thereby reduce the peak power.

Orthogonal frequency multi-carrier transmission device and transmission method

A transmission apparatus used in a radio communication system adopting the OFDM scheme is disclosed. The transmission apparatus includes: a dividing inverse Fourier transform part including plural transform parts, wherein the dividing inverse Fourier transform part divides a signal to be transmitted into plural signals, and each of the plural transform parts performs inverse Fourier transform on one of the plural signals; a peak control part for outputting a peak control signal based on peaks that are detected from output signals of the dividing inverse Fourier transform part; and a peak reducing process part for adjusting a weight or an arranging order of an output signal of the dividing inverse Fourier transform part according to the peak control signal to output an adjusted signal, and synthesizing the adjusted signal with other signal so as to output a synthesized signal.

Transmission apparatus and receiving apparatus

An object of the present invention is to provide a communications system etc., which can reduce the influence of interference from other systems which results from a difference in symbol length, in an area where a plurality of systems using different transmission methods are mixed. The present invention relates to a communications system in which a plurality of systems share the same frequency bandwidth so as to transmit information symbols. One of the plurality of systemsincludes an identifying unitconfigured to identify the symbol length of an information symbol transmitted in a different system; and an adjusting unitconfigured to adjust the symbol length of an information symbol to be transmitted, in accordance with an identified symbol length.

Communications system, communications method, transmitting apparatus, receiving apparatus and control program to variably adjust a symbol length

An OFDM signal frame generator includes a rate determiner configured to determine rate information to generate a signal frame to be transmitted as an OFDM signal based on a value of a received signal quality. The signal frame generator further includes a pilot and data arrangement format determiner configured to determine a pilot and data arrangement format of the signal that is to be transmitted; power amplification rate determiner configured to determine a power amplification rate for the signal frame; data symbol generator configured to generate data symbol series to be transmitted based on the rate information and based on the power amplification rate; and transmission signal frame generator configured to generate the signal frame based on the generated data symbol series, on the number of pilot symbols, and based on the pilot & data arrangement format.

OFDM signal frame generator, transmitter, signal transmission system and OFDM signal frame generating method

A repeating station, a communication apparatus, and an antenna directivity control method are disclosed. The repeating station includes

Repeating station, a communication apparatus, and a directivity control method

A radio communication system including a transmitter and a receiver () for transmitting MIMO channel signals is provided. The transmitter comprises a pilot signal insertion controller () for inserting a pilot signal for channel estimation into at least a leading frame; and an information symbol controller for controlling the number of information symbols to be contained in a frame, based on the existence of the pilot signal. The receiver comprises a received signal replica generator () for generating received signal replicas based on previously obtained provisional channel estimation values and transmission signal estimation values; a canceller () for removing, from a received signal, received signal replicas of at least a part of streams that are not channel estimation target streams; and a channel estimation value generator () for generating channel estimation values by a filter using outputs from the removing unit and the transmission signal estimation values.

Receiver, a transmitter, a radio communication system and a channel estimation method

Growing community of inventors

Yokosuka, Japan

Hirohito Suda