Abstract: A data signal component output from a reference signal demultiplexer and channel state information obtained by using DM-RS output from a channel estimating unit are input into a modulo estimating unit. In a channel compensator, a first provisional decision value sequence is calculated on the basis of the channel state information. The first provisional decision value sequence is input into a modulo calculator, and modulo calculations are performed on the first provisional decision value sequence to obtain a second provisional decision value sequence. A decision-feedback channel estimating section finds a first channel estimation value based on the first provisional decision value sequence and a second channel estimation value based on the second provisional decision value sequence. A modulo decision section decides whether or not a perturbation term has been added to a code, and uses a decision result for the selection of a demodulation method.

Abstract: A radio receiving apparatus is notified of whether a multi-user multiplexing transmission signal that is transmitted from a radio transmitting apparatus is the multi-user MIMO or the OFDMA without increasing a control information amount. The radio transmitting apparatus includes a scheduling section 115 that selects any one group from a plural groups that represent combinations of the plural radio receiving apparatuses, and a transmit symbol generating section 125 that generates a transmit signal by multiplexing data to be transmitted to the plural radio receiving apparatuses belonging to the selected group by the multiplexing method in advance determined corresponding to an identification number added to the selected group.

Abstract: A terminal device knows which kind of pre-coding has been applied without increasing overhead in a wireless communication system in which plural kinds of pre-coding are selectively or simultaneously used. A pre-coding device that is applied to a wireless communication device that performs wireless communication with a wireless receiving device applies, based on control information obtained from the wireless receiving device, the pre-coding to a data signal and plural kinds of specific reference signals, provides phase rotation to the plural kinds of specific reference signals, and associates phase rotation amounts of the phase rotation with information that is notified to the wireless receiving device.

Abstract: A wireless reception device is notified of whether a multi-user MIMO signal transmitted from a wireless transmission device has undergone linear precoding or non-linear precoding without increasing the amount of control information. A wireless transmission device having a plurality of transmit antennas 303, for transmitting spatially multiplexed signals to a plurality of wireless reception devices includes a group construction unit 307 configured to classify the wireless reception devices into a plurality of groups and to determine a precoding scheme for each of the groups, a selection unit 315 configured to select one group from among the groups, and a precoding unit 323 configured to precode transmit data addressed to each of wireless reception devices belonging to the selected group, using a precoding scheme determined for the selected group.

Abstract: A data signal component output from a reference signal demultiplexer and channel state information obtained by using DM-RS output from a channel estimating unit are input into a modulo estimating unit. In a channel compensator, a first provisional decision value sequence is calculated on the basis of the channel state information. The first provisional decision value sequence is input into a modulo calculator, and modulo calculations are performed on the first provisional decision value sequence to obtain a second provisional decision value sequence. A decision-feedback channel estimating section finds a first channel estimation value based on the first provisional decision value sequence and a second channel estimation value based on the second provisional decision value sequence. A modulo decision section decides whether or not a perturbation term has been added to a code, and uses a decision result for the selection of a demodulation method.

Abstract: More reduction of the amount of operation than in QRM-VP is realized while maintaining transmission performance that can be achieved by VP.

Abstract: The current feedback mechanisms in the 802.11 standard are not appropriate for MU-MIMO, in which many STAs transmit their feedback to an AP, which then proceeds to select the most appropriate STAs for transmission and discards the feedback of the rest of the STAs. This operation leads to large overhead, effectively limiting the effectivity of the MU-MIMO operation. The techniques described in this document allow for a more efficient transmission of feedback related to a MIMO communication. In this invention a double step feedback method is proposed trough which the STAs first transmit a reduced feedback enabling the AP to perform scheduling, and then the STAs that are chosen for scheduling transmit complementary feedback for the only the streams that are chosen by the scheduling operation. This operation results in a much more efficient feedback transmission.

Abstract: The present invention switches an interference suppression system between a linear precoding and a nonlinear precoding in accordance with a communication environment. A wireless transmission apparatus is provided with a plurality of transmission antenna units (303), and multiplexes spatially and transmits a plurality of series of data with respect to at least one wireless reception apparatus, and includes a selection unit (307) configured to select any one precoding system from a plurality of types of precoding systems and a precoding unit (315) configured to carry out precoding with respect to the plurality of series of data using the selected precoding system. In addition, the selection unit selects either of a first precoding system carrying out linear processing with respect to the plurality of series of data or a second precoding system carrying out nonlinear processing with respect to the plurality of series of data.

Abstract: A filter calculating device includes a first equalization filter calculating section that generates at least a first conversion matrix and a first triangular matrix based on a channel state of a first channel; a first quasi-orthogonalization section that calculates a first unimodular matrix based on the first triangular matrix; and a second equalization filter calculating section that generates at least a second conversion matrix and a second triangular matrix based on a channel state of a second channel and the first unimodular matrix.

Abstract: A terminal device notifies a base station device about control information associated with a receive quality of the terminal device. The base station device performs data modulation on a plurality of pieces of transmit data for the terminal device, by using a plurality of different data modulation schemes one by one, based on the control information, and spatially multiplexes the plurality of pieces of transmit data after the data modulation over a single wireless resource and transmits a spatially multiplexed signal. The terminal device receives the signal with the plurality of pieces of transmit data spatially multiplexed, and detects desirable transmit data from the receive signal, based on a first channel matrix which represents channel state information between the base station device and the terminal device and a second channel matrix in which the first channel matrix is multiplied by a transform matrix.

Abstract: A wireless communication system in which a base station apparatus having a plurality of transmission antennas and one or more terminal apparatuses communicate with each other is provided with at least two methods of a first feedback method and a second feedback method regarding propagation path information at the time of reception. In accordance with a communication condition between the base station apparatus and the terminal apparatus, or the function of the terminal apparatus, the terminal apparatus performs feedback by one of the two methods of the first feedback method and the second feedback method. The base station apparatus performs spatial multiplexing transmission on the basis of the propagation path information that has been fed back. Thus, in a system in which CSI is fed back for MIMO transmission, desired transmission characteristics can be efficiently obtained.

Abstract: A wireless communication system includes a base station apparatus having a plurality of antennas and a plurality of mobile station apparatuses each having, at least, one antenna. The base station apparatus acquires channel state information of the plurality of mobile station apparatuses, based on any one of a plurality of different channel state information formats, and, separately precodes data signals addressed to the plurality of mobile station apparatuses based on the channel state information, and spatially multiplexes and transmits the precoded signals. The mobile station apparatus receives the precoded signals and detects a desired data signal from the multiplexed signals addressed to mobile station apparatuses, based on the channel state information.

Abstract: In a codebook-based closed loop type MIMO, improvement for complexity in a mobile station apparatus, and reduction of amount of overhead needed for notification from the mobile station apparatus should be provided. A wireless transmission apparatus that includes a plurality of transmission antennas, performs precoding on a data signal for each of a plurality of reception apparatuses and spatially multiplexes and transmits the signal after the precoding. The wireless transmission apparatus performs sharing a codebook describing a plurality of linear filters associated with each other is shared with the each reception apparatus, and precoding on the data signal for each reception apparatus, based on a first linear filter that is extracted from the codebook in each reception apparatus based on the association and that is notified from each reception apparatus.

Abstract: Provided is a radio communication system in which a base station apparatus with a plurality of transmission antennas spatially multiplexes and transmits a transmission signal addressed to a plurality of mobile station apparatuses, and in which the mobile station apparatuses receive the signal transmitted from the base station apparatus. The mobile station apparatuses select a desired precoding vector from predetermined candidates, and give the base station apparatus information identifying the selected precoding vector.