Abstract: To facilitate selection of an optimal PMI corresponding to a channel variance in a channel propagation path, in a method of controlling codebooks comprised of a plurality of DFT codebooks for defining precoding matrixes that are selected when correlation between antennas in a base station apparatus (eNode B) is high and a plurality of random codebooks for defining precoding matrixes that are selected when correlation between antennas in the base station apparatus (eNode B) is low, a channel variance in a channel propagation path is estimated, and based on the estimated channel variance, the configuration ratio between the DFT codebooks and the random codebooks included in the codebooks is varied adaptively.

Abstract: The present invention makes it possible to generate precoding weights reliably, even in downlink MIMO transmission using a plurality of transmitting antennas. The present invention includes: a first feedback information selection section (109) that, in a mode to include a PTI in a PUCCH and feed back the PTI to a radio base station apparatus for downlink MIMO transmission using a plurality of transmitting antennas, selects the same RI as the last RI that was fed back, when the value of the PTI is changed from 0 to 1; a multiplexer (115) that multiplexes the RI and the PTI after the change on a subframe; and a transmission section that transmits the multiplex signal to the radio base station apparatus by the PUCCH.

Abstract: Disclosed is a mobile terminal device and a radio base station apparatus capable of effectively feeding back PMIs by selecting a precoder using double codebooks W1 and W2 in downlink MIMO transmission. The mobile terminal device includes a feedback control signal generating section that individually performs channel coding for the first PMI selected from the first codebook for wideband/long-period and the second PMI selected from the second codebook for subband/short-period and a transmit section that transmits the individually channel-coded first and second PMIs to the radio base station apparatus on a physical uplink shared channel (PUSCH).

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: 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: 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 directed to preventing the load to be required for blind detection in a mobile station apparatus (UE) from increasing and switching between SU-MIMO and MU-MIMO dynamically, even in the event the system bandwidth is expanded. The present invention has a DCI format selection section (209) that selects identification information which identifies between a DCI format for SU-MIMO and a DCI format for MU-MIMO, a control signal generation section (210) that generates control signals including the identification information and including the DCI format for SU-MIMO or MU-MIMO, having the same number of bits, and a transmission section that transmits the control signals to a mobile station apparatus.

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 receiver includes a receiving unit for scanning a dedicated signaling channel for the presence of an announcement signal. The announcement signal indicates a transmitter willing to access a transmission medium. The receiving unit is further operative to receive a data signal from a further transmitter on a dedicated traffic channel. Furthermore, the receiver includes an interference estimator for estimating, whether an interference caused by a new transmitter is allowable or not. A processor is provided for applying an interference counter-measure, when the interference is not allowable. A transmitter can, without any limitation, transmit the announcement signal. The transmitter will start transmitting, when it receives a ready-to-receive signal from the addressed receiver and when it does not receive an objection tone from another receiver in the network.

Abstract: Apparatus and method of providing an estimate of a transmit sequence from a receive sequence. The transmit sequence includes transmit sequence values. The transmit sequence value is transmittable by one of a group of transmitting points through a communication channel of a plurality of communication channels to a receiving point. The communication channel extends from a transmitting point to a receiving point. The receive sequence includes an interference of transmit sequence values.

Abstract: A receiver includes a receiving unit for scanning a dedicated signaling channel for the presence of an announcement signal. The announcement signal indicates a transmitter willing to access a transmission medium. The receiving unit is further operative to receive a data signal from a further transmitter on a dedicated traffic channel. Furthermore, the receiver includes an interference estimator for estimating, whether an interference caused by a new transmitter is allowable or not. A processor is provided for applying an interference counter-measure, when the interference is not allowable. A transmitter can, without any limitation, transmit the announcement signal. The transmitter will start transmitting, when it receives a ready-to-receive signal from the addressed receiver and when it does not receive an objection tone from another receiver in the network.

Abstract: An apparatus for providing an estimate of a transmit sequence from a receive sequence has a processor for processing the receive sequence to obtain a permuted filtered sequence, wherein the processor is operative for processing the receive sequence using channel information and permutation information. The apparatus further comprises means for providing information on an estimation error associated with the estimate of the transmit sequence, means for calculating the permutation information using the estimation error, wherein the means for calculating is operative for calculating the permutation information such that the permuted filtered sequence values are in such an order that estimation error values associated with the values of the estimate of the transmit sequence are in a predetermined order, and an interference canceller for reducing interferences by performing a subtraction operation using the permuted filtered sequence to provide the estimate of the transmit sequence.