Nec Corporation

Ntt Docomo, Inc.

Fujitsu Corporation

Lenovo Innovations Limited (hong Kong)

Shousei Yoshida

Akihisa Ushirokawa

Masayuki Kimata

Yoshikazu Kakura

Kojiro Hamabe

Naoto Ishii

Yasushi Maruta

Hiroshi Furukawa

Kengo Oketani

Hironori Mizuguchi

Mariko Matsumoto

Noriyuki Maeda

Susumu Otani

Takumi Ito

Mamoru Sawahashi

Kenichi Higuchi

Toshifumi Sato

Junichiro Kawamoto

Yasunori Futatsugi

Hisashi Futaki

Hiroyuki Seki

Hiroyuki Atarashi

Takamichi Inoue

Kenji Koyanagi

Hizuru Nawata

Hiroyuki Kawai

Toshiya Todoroki

Shingo Kikuchi

Yoshio Tanimoto

A memoryof a pilot processing circuitholds in advance a pilot sequence converted into a frequency region signal obtained by subjecting a pilot signal symbol transmitted in one block to Ntx_p-point DFT. The pilot sequence held in the memoryis subjected to a series of processes including a roll-off filtering by a roll-off filter circuit, subcarrier mapping process by subcarrier mapping circuit, an Ndft_p-point IDFT operation by an IDFT circuit, and a cyclic prefix adding process by a cyclic prefix adding circuit

Single carrier transmission system, communication device, and single carrier transmission method using for them

In a reception method and a receiver, a base station corrects a frequency offset contained in a reception signal from each user terminal and realizes excellent reception characteristics by using a simple receiver mechanism for performing frequency domain processing in a radio system using a frequency division multiplex (FDM) method. The base station includes: a DFT section that converts reception signals from a plurality of mobile stations communicating by radio communication using FDM all at once into the frequency domain; a demapping section that recognizes, from the frequency domain signals, user signals corresponding to respective mobile stations by using sub-carriers selected in association with respective mobile stations; a correction signal generation section generating a correction signal correcting a user signal frequency offset for each user signal; a frequency conversion section that corrects the frequency offset of the user signal by the correction signal; and a demodulation section that demodulates each of the corrected user signals.

Reception method and receiver

A reference signal of a user equipment to which a resource (LB#) is allocated for a L1/L2 control signal, is allocated a resource (SB#) that is closer on the time axis to the resource (LB#), which the L1/L2 control signal is allocated, within the same frequency band as the L1/L2 control signal. A reference signal for CQI estimation, independent of a data signal and a L1/L2 control signal, is allocated a resource with which at least one of a reference signal for demodulation of a data signal and a reference signal for demodulation of a L1/L2 control signal is not transmitted at the same timing within the transmission band. The types of bandwidths of the reference signals multiplexed in a same short block within a same band are reduced, whereby restrictions as to the number of reference signal sequences that can be secured are diminished.

Reference signal multiplexing and resource allocation

In a MIMO receiving apparatus, the signals of single carriers transmitted from a plurality of transmission antennas are received by a plurality of reception antennas (-through-N) and then separated according to frequency ranges. In this MIMO receiving apparatus, interference replicas of the antennas are eliminated from the received signals (by subtractor) before equalizing the two-dimensional frequency ranges, and non-distortion signal replicas are added (by a demodulating part) to the signals from which the interference replicas of the antennas have been eliminated after equalizing the two-dimensional frequency ranges.

MIMO receiving apparatus and receiving method

A radio communication device for receiving a single-carrier signal transmitted in a partial spectrum of Nyquist frequency band, includes: an interference eliminator for eliminating interference from a received signal by spectrum reproduction of non-transmitted spectra using a symbol replica, to output an interference eliminated signal, wherein the interference includes intersymbol interference which is caused by symbols which are more than a predetermined distance away from a decision symbol point; a symbol sequence estimator for estimating a transmission symbol sequence by separating nearby intersymbol interference within the predetermined distance of the decision symbol point based on the interference eliminated signal, to output a decision signal; and a replica generator for generating the symbol replica from decoding result of the decision signal, wherein the symbol replica is fed back to the frequency-domain interference eliminator.

Radio communication method and device in single-carrier transmission system

A receiving apparatus is provided in which a single carrier signal is received by a plurality of receiving antennas, and multipath equalization and other cell interference suppression are carried out in a frequency domain at a same time. A plurality of antennas-to-N receives the single carrier signal. The DFT sections-to-N converts the reception signals into frequency domain signals. A channel estimating sectionestimates a channel gain of a desired user signal by using pilot reception signals. An interference correlation matrix estimating sectionestimates an interference correlation matrix from the pilot reception signals and a channel estimation value. A weight calculating section. A weight calculating sectionreceives the channel estimates and the interference correlation matrix and calculates equalization weights. An equalizing sectionperforms multipath equalization and other cell interference suppression to the desired user signal in a frequency domain. An IDFT sectionconverts an equalization signal into a signal in a time domain.

Receiving apparatus and mobile communication system

A MIMO wireless communication system capable of relaxing a reduction in a transmission rate on a cell end far from a base station and ensuring a high transmission rate for a mobile station, irrespectively of a distance from the base station is provided. In a state, the mobile stationchecks a propagation line quality and instructs only the first base stationto transmit data to the mobile station In a state, the mobile stationissues a request to divide the data to the first base stationand the second base stationand to transmit the divided data to the mobile station, and holds MIMO communication with the two base stations. In a state, the mobile stationrequests only the second base stationto transmit the data and communicates with the second base station

MIMO wireless communication system and method by a plurality of base stations and mobile station

A priority computation process computes a priority of each user for each RB (Resource Brock) using a reception SINR. A maximum priority user selection/RB allocation process selects a user with the maximum priority for an unallocated RB and allocates the RB to the user. A frequency axis/space axis unallocated RB presence determination process proceeds to scheduling for a next user if there is an unallocated RB on the frequency or space axis. A projected channel vector update process updates a projected channel vector of an unselected user by GS orthogonalization. An orthogonal coefficient computation process computes an orthogonal coefficient. A corrected SINR computation process computes a corrected SINR. A next MIMO layer priority computation process computes priorities of unselected users for a corresponding RB in the next multiple MIMO layer. The priorities of the unselected users are used in the next user scheduling processing.

Scheduling method for multi-user MIMO in which resource blocks are allocated based on priorities

A transmitting device according to the present invention comprises: a coding unit which encodes a transmission information bit string to a code bit string; a low-order modulating unit which conducts low-order modulation on the code bit string outputted from the encoding unit; a first frequency domain converting unit which converts the low-order modulated signal outputted from the low-order modulating unit to a frequency domain signal; a partial spectrum selecting unit which selects a central 1/M portion (M is an integer greater than or equal to two) of a spectrum from the frequency spectrum outputted from the first frequency domain converting unit; and a first time domain converting unit which converts the spectrum selected signal outputted from the partial spectrum selecting unit to a time domain signal.

Transmitting device, transmitting/receiving device, transmitting method and transmitting/receiving method

Provided are a channel estimation device and an equalization device capable of achieving high channel estimation accuracy with less amount of calculation processing. The equalization device includes: a channel estimation section including a ZF calculation/clipping processing section and correlation processing section; a weight calculation section; and an equalization filter. The ZF calculation/clipping processing section uses a signal obtained by converting a pilot code into a frequency domain to calculate a pilot reference signal according to a Zero Forcing (ZF) method and clips the gain of the calculated pilot reference signal to a predetermined value to generate a clipped pilot reference signal. The correlation processing section performs correlation between a pilot reception signal in the frequency domain and clipped pilot reference signal to estimate channel characteristics of the frequency domain. The weight calculation section calculates an equalization weight based on the channel characteristics of the frequency domain. The equalization filter performs equalization processing of a frequency domain reception signal using the equalization weight.

Channel estimation device, equalization device, and radio system

A corrected channel estimating apparatus is disclosed, which is capable of removing side-lobe components mutually leaking into transmission paths from channel estimates to increase the accuracy. A channel estimation unit calculates channel estimates for a plurality of transmission paths due to a signal that arrives through multipath. A channel estimate correction unit removes side-lobe components mutually leaking into the transmission paths from the channel estimates calculated by the channel estimation unit to correct the channel estimates. In this way, the corrected channel estimating apparatus estimates transmission paths of a multipath.

Channel estimating apparatus, CDMA receiving apparatus, and channel estimating method

A receiver uses a transmission channel matrix to obtain a superior signal separation characteristic regardless of differences in levels of multipath signals. A multipath linear combining unit performs linear combining of the multipaths in received signals of the reception antennas by means of the transmission channel matrix between the plurality of transmission antennas and the plurality of reception antennas. A maximum likelihood detector compares signals in which multipaths have been combined by the multipath linear combining unit with reception replicas that have been found using the transmission channel matrix to estimate the transmitted signals of each of the transmission antennas.

Radio communication system that uses a MIMO receiver

The present invention aims to provide a user selection method which can provide a large, multiuser diversity effect with a small amount of calculation in multiuser MIMO systems, the method being a user selection method for multiuser MIMO communication, in which an orthogonal coefficient is calculated using a received SINR from a projection channel vector by using GS orthogonalization, and using the orthogonal coefficient, a correction SINR is calculated, and using this correction SINR, user selection is performed, and for a next user selection, the projection channel vector is updated, and the above processes are applied to all users.

User selection method and user selection device for multiuser MIMO communication

A receiving apparatus, a receiving method, and a radio communications system are disclosed. The receiving apparatus is for receiving CDMA signals transmitted by M antennas and received by N antennas, where M and N are positive integers. The receiving apparatus includes a multipath receiving signal demodulating unit for primary demodulation of the CDMA signals received by the receiving antennas to obtain estimated transmission signals, and for obtaining signals in a multipath environment of each path of the receiving antennas based on the estimated results. Further, the receiving apparatus includes a multipath interference canceling unit for deducting signals of the paths other than a target path from the signals received by the receiving antennas to obtain multipath interference cancelled signals. Further, the receiving apparatus includes a demodulator for secondary demodulation of the multipath interference cancelled signals.

Growing community of inventors

Tokyo, Japan

Shousei Yoshida