Abstract: A precoding weight generation method involves generating a channel matrix having channel state information transmitted as feedback from mobile stations undergoing spatial multiplexing for each cell that base stations manage, and generating precoding weights. When data transmission is targeted for a first mobile station that transmits the channel state information as feedback as well as transmits the channel state information to a weight generation target cell that is a target for generation of precoding weights, precoding weights are generated so as not to suppress interference on a second mobile station that transmits the channel state information as feedback as well as transmits the channel state information to the weight generation target cell, while suppressing interference on a third mobile station that does not transmit the channel state information as feedback except to the weight generation target cell.

Abstract: To perform feedback of channel information suitable for MU-MIMO transmission while exploiting a codebook that defines precoding matrixes and PMIs suitable for SU-MIMO transmission, it is a feature that a channel matrix corresponding to a channel transmission path is defined using a plurality of precoding matrixes defined in a codebook suitable for SU-MIMO transmission and a plurality of adjustment coefficients to respectively adjust the plurality of precoding matrixes, a channel information selecting section (111) selects a plurality of precoding matrixes and/or a plurality of adjustment coefficients, and that the selected plurality of precoding matrixes and/or the plurality of adjustment coefficients are transmitted to a base station apparatus as channel information in uplink.

Abstract: A communication apparatus to be used for a newer system employing an FDD scheme in an area where an older system and the newer system coexist. The communication apparatus includes a first communication unit communicating at least a downlink data channel of the newer system using a frequency band belonging to a first frequency range (3.4-3.8 GHz); and a second communication unit communicating at least an uplink control channel of the newer system using a frequency band belonging to a second frequency range (2 GHz band) lower than the first frequency range. The second frequency range is used for uplink and downlink communications in the older system.

Abstract: A base station apparatus in a mobile communications system has a unit which transmits, to one or more user apparatuses, a downlink control signal including information for allocating a radio resource, a unit which receives an uplink signal from the one or more user apparatuses, and a unit which determines, based on a feedback from the user apparatus, a pre-encoding matrix indicator (PMI) indicating a pre-encoding matrix to be applied to multiple antennas of the base station apparatus. When a number of multiplexed users in the downlink control signal is no less than a predetermined number, the PMI indicating the pre-encoding matrix to be applied to a whole system bandwidth of the mobile communications system is reported to each of the user apparatuses.

Abstract: The present invention reduces the increase of the amount of feedback information, and, regardless of whether the correlation between antennas is high or low, increases the data rate upon MIMO transmission.

Abstract: The present invention is designed to implement radio communication to maintain good communication quality even when the number of antennas provided in a radio base station apparatus is greater than the number of transmission layers of a downlink control channel, a broadcast channel, and cell-specific reference signals. When, from a radio base station apparatus (200) having a plurality of transmitting antennas, at least one of a downlink control channel, a broadcast channel and a cell-specific reference signal is transmitted with fewer transmission layers than the number of all transmitting antennas, a smaller number of antennas than the number of all transmitting antennas are made virtual in a precoding weight multiplication section (205), and also transmission weights that make the average transmission power of the transmitting antennas or transmission streams the same are multiplied, and the signals multiplied by the transmission weights are transmitted from the transmitting antennas on the downlink.

Abstract: To notify the control information necessary for uplink MIMO transmission while reducing overhead, generated is a UL grant having the PMI/RI field and non-transmission/swap flag field of 1 bit indicative of a transport block made non-transmission and the presence or absence of a swap of control information between two transport blocks corresponding to a value of the PMI/RI field, a downlink control channel signal including the UL grant is transmitted to a mobile station apparatus, and the transport block made non-transmission and the presence or absence of a swap of control information between two transport blocks is determined from the non-transmission/swap flag of the UL grant.

Abstract: The present invention provides a mobile terminal apparatus and a radio communication method which can feed back precoders that are essential to generate precoding weights in downlink MIMO transmission. With the present invention, in the first mode to feed back subband second PMIs that are selected per bandwidth part through a physical uplink control channel, a subband second PMI and a wideband second PMI are selected from a second codebook, the subband second PMI and the wideband second PMI are multiplexed on a subframe, and the multiplex signals is transmitted to a radio base station apparatus through the above physical uplink control channel.

Abstract: In order to suppress deterioration of the throughput performance of the whole system in the MIMO system performing MIMO transmission, the present invention is characterized in that in a codebook in which there are defined a plurality of precoding weights and a plurality of PMIs (Precoding Matrix Indicators) assigned to the precoding weights, bit information of the PMIs assigned to the precoding weights is adjusted in such a manner as to suppress an effect of feedback error from a mobile station apparatus. The bit information of the PMIs assigned to the precoding weights is adjusted in such a manner as to suppress an effect of a transmission beam formed with a PMI in which feedback error is detected.

Abstract: A data transmission method includes, in the mobile station apparatus, selecting a PMI and an RI corresponding to an Hermitian transpose of a channel matrix indicative of channel characteristics and calculating a CQI from the PMI. The method further includes transmitting the PMI, the RI, and the CQI to the base station apparatus as feedback information. The method further includes, in the base station apparatus, calculating a first data rate of a case of performing SU-MIMO transmission based on the PMI transmitted from the mobile station apparatus as feedback and calculating a second data rate of a case of performing ZF MU-MIMO transmission based on the PMI. The method further includes selecting a transmission scheme corresponding to a higher data rate between the first and second data rates.

Abstract: A user apparatus to which radio access schemes that are a single-carrier scheme and a multicarrier scheme are applied, includes: a radio access scheme setting unit configured to set a radio access scheme; a discrete Fourier transform unit configured to perform discrete Fourier transform on a modulated symbol sequence when the set radio access scheme is the single-carrier scheme; a serial parallel conversion unit configured to perform serial parallel conversion on a modulated symbol sequence when the set radio access scheme is the multicarrier scheme; a frequency domain signal generation unit configured to assign a radio resource to the modulated symbol sequence on which discrete Fourier transform has been performed or to the modulated symbol sequence on which serial parallel conversion has been performed to generate a frequency domain signal; a transmission signal generation unit configured to perform inverse fast Fourier transform on the frequency domain signal to generate a transmission signal; a transmissi

Abstract: The present invention provides a reception apparatus and reception method that reduce the amount of operation processing, reduce the processing delay and allow high signal separation performance. The reception method of the present invention is characterized by receiving signals including a plurality of codewords transmitted by a plurality of streams and performing maximum likelihood detection-based signal separation in the same codeword in the received signals while performing continuous interference canceller-based signal separation between different codewords.

Abstract: A data rate in MIMO transmission is increased to a maximum even when the number of transmitting antennas of a mobile station apparatus is different from the number of transmitting antennas of the mobile station apparatus supported by a base station apparatus. The base station apparatus (eNodeB) reports the maximum number of supported antennas of the mobile station apparatus (UE) supported by the base station apparatus (eNodeB) to the mobile station apparatus (UE) (ST11). The mobile station apparatus (UE) compares the number of supported antennas with the number of transmitting antennas of the mobile station apparatus (UE), selects the smaller number of antennas as a number of virtual antennas (ST12), and reports the number of virtual antennas to the base station apparatus (eNodeB) (ST13). The base station apparatus (eNodeB) instructs the mobile station apparatus to transmit a data channel signal in accordance with the number of virtual antennas (ST15).

Abstract: The data rate in MIMO transmission is increased to a maximum even when a number of transmitting antennas of a base station apparatus is different from the number of transmitting antennas of the base station apparatus supported by a mobile station apparatus. The base station apparatus (eNodeB) reports the number of transmitting antennas provided for the base station apparatus to the mobile station apparatus UE (ST11). The mobile station apparatus UE compares the reported number of transmitting antennas with a maximum number of supported antennas of the base station apparatus (eNodeB) supported by the mobile station apparatus UE, selects the smaller number of antennas as a number of virtual antennas (ST12), and reports the number of virtual antennas to the base station apparatus (eNodeB) (ST13). The base station apparatus (eNodeB) transmits a data channel signal in accordance with the reported number of virtual antennas (ST15).

Abstract: To increase a data rate (spectral efficiency) of the entire system also in the case of dynamically switching between SU-MIMO transmission and MU-MIMO transmission, it is a feature that a mobile station apparatus (10) selects a PMI associated with a precoding matrix including matrix elements corresponding to a stream that most approximates a channel matrix indicative of a channel state in a channel transmission path to transmit to a base station apparatus (20) as feedback, and that the base station apparatus (20) extracts the matrix elements corresponding to the stream that most approximates the channel state in the channel transmission path from the precoding matrix associated with the PMI transmitted from the mobile station apparatus (10) as feedback, and based on the extracted matrix elements, generates precoding weights.

Abstract: A disclosed base station apparatus is capable of communicating with a user equipment terminal in a multi-input multi-output (MIMO) mobile communication system using Pre-coding. The base station apparatus includes a receiving unit receiving a Pre-coding Matrix Indicator (PMI) indicating a specific Pre-coding matrix, a determination unit determining a value of a flag indicator indicating whether the Pre-coding matrix specified in the PMI is to be used for downlink communications, a control signal generation unit generating a downlink control signal including at least the flag indicator, and a transmission unit transmitting a signal including the downlink control signal in downlink.

Abstract: To suppress deterioration of throughput characteristics in the entire system even when a plurality of transmission antennas is placed in an indoor environment, a base station apparatus (eNode B) is provided with a power control matrix generating section (508b) that generates a power control matrix (Sx) reflecting average reception power of each of transmission signals from a plurality of transmission antennas (TX#1 to TX#NTX), a codebook update section (508c) that updates a codebook which beforehand defines a plurality of precoding weights corresponding to the power control matrix (Sx), a precoding weight selecting section (508d) that selects precoding weights that maximize throughput or reception SINR obtained after combining the transmission signals from the updated codebook, and a precoding multiplying section (transmission power control section) (507) that controls transmission power of each of the transmission signals corresponding to the selected precoding weights.

Abstract: To suitably transmit feedback information for rank adaptation and precoding in uplink MIMO transmission to a user apparatus as feedback, a base station apparatus (200) is characterized by having a precoding weight/rank number selecting section (232) that determines rank information associated with the number of layers of spatial multiplexing in uplink, while determining a control amount of a transmission phase and/or transmission amplitude used in weighting for transmission antennas of a user apparatus, and transmission/reception sections (206a), (206b) that transmit the rank information determined in the precoding weight/rank number selecting section (232) to a mobile station (100) using an RRC signal, while transmitting the control amount to the mobile station (100) using a control channel signal.

Abstract: Provided are a mobile terminal apparatus, a radio base station apparatus and a radio communication method, capable of saving PHICH resources enough and realizing effective retransmission control of uplink SU-MIMO. The radio communication method of the present invention is characterized in that a radio base station apparatus receives signals of plural codewords, when there is an error in each of the codewords, generates a one-bit negative response physical HARQ indicator channel signal and transmits the physical HARQ indicator channel signal, and a mobile terminal apparatus receives the physical HARQ indicator channel signal and transmits retransmission signals of all the codewords to the radio base station apparatus based on the negative response physical HARQ indicator channel signal.

Abstract: A transmitter includes multiple transmit antennas, a conversion unit configured to generate multiple signal sequences corresponding to a predefined frequency bandwidth from one or more transmission streams associated with any of the transmit antennas, a precoding unit configured to weight the signal sequences with a precoding matrix selected from a codebook including multiple predefined precoding matrices, and a transmitting unit configured to convert an output signal from the precoding unit into a number of signals corresponding to the number of transmit antennas and transmit the converted signals from the transmit antennas. The precoding unit applies distinct precoding matrices to different signal sequences, and an association between the distinct precoding matrices and the different signal sequences is determined through open-loop control being independent of a feedback from a receiver.