Abstract: The present invention provides a base station apparatus capable of preventing degrading of throughput performance even when feedback information amount on precoding in uplink MIMO transmission is reduced. This base station (200) has a scheduler (231) for determining resource blocks used in wireless communications with each mobile station (100) adaptively, a precoding weight selecting section (232) for selecting a precoding weight for controlling phase and/or amplitude of a transmission signal for each antenna in the mobile station (100) based on reception quality on uplink at the resource blocks determined to the mobile station (100); and transmission/reception sections (206a and 206b) for transmitting the determined precoding weight to the mobile station (100).

Abstract: An approach for resource allocation in a wireless communication network including a sender, a relay station and a receiver in case of a retransmission of information from the relay station to the receiver is described, wherein a resource necessary for retransmission is determined on the basis of the relayed channel and the relay function.

Abstract: In order to reduce the amount of feedback information for specifying a precoding weight, the mobile station apparatus generates a control signal for specifying the precoding weight using bits representing a rank indicator (RI) and bits representing a precoding matrix indicator (PMI) from a bit space, including a plurality of bits representing the RI and a plurality of bits representing the PMI, in which the same bits representing the RI are allocated to a plurality of ranks equal to or higher than a predetermined rank. The control signal is transmitted in uplink using the antennas.

Abstract: The communication apparatus includes: a processing unit 52 configured to determine a data modulation scheme for each stream based on first signal quality q1 for each stream determined by the MMSE method; a processing unit 54 configured to determine second signal quality q2 corresponding to the first signal quality q1; a processing unit configured to determine third signal quality q3(1) of a stream by adding first signal quality q1(1) of the stream and a correction value ?q(1) derived from second signal quality q2(2) of equal to or more than 1 stream other than the stream; and a processing unit 58 configured to determine channel coding rate Rk corresponding to third signal quality q3(1) for each stream. The determined data modulation scheme and channel coding scheme are used for transmission of a following stream.

Abstract: Disclosed are a receiving apparatus, a data receiving method, a channel estimating apparatus and a channel estimating method for multi-user interference (MUI) signals according to the present invention. The channel estimating apparatus for MUI signals has: a user type determining section configured to determine whether a UE apparatus corresponding to an own station belongs to a first type user or a second type user and to determine demodulation information to use in channel estimation of MUI signals based on the type of the UE apparatus corresponding to the own station; and a second channel estimating section configured to perform channel estimation of a multi-user interference signal based on the determined demodulation information to use in channel estimation of MUI signals. In the present invention, the UE apparatus is classified by type and the demodulation information to use in channel estimation of MUI signals is determined based on the type of the UE apparatus.

Abstract: A base station for communicating with a first user equipment terminal within a first system band and communicating with a second user equipment terminal within a second system band includes a first reference signal sequence generating unit configured to generate M types of reference signal sequences; a second reference signal sequence generating unit configured to generate N (N>M) types of reference signal sequences; a scheduling unit configured to allocate resource blocks to the first user equipment terminal and the second user equipment terminal; a signal multiplexing unit configured to multiplex the M types of reference signal sequences into the resource block for the first user equipment terminal and multiplex the N types of reference signal sequences into the resource block for the second user equipment terminal; and a transmitting unit configured to transmit signals including the M types of reference signal sequences and the N types of reference signal sequences.

Abstract: A method transmits data from a first terminal of a wireless communication system to a second terminal of the wireless communication system. The wireless communication system has a core network and at least one radio access network coupled to the core network. Data is transmitted from a first terminal of the wireless communication system to a second terminal of the wireless communication system co-located in a common coverage area of the at least one radio access network. The data is transmitted from the first terminal to the second terminal via the entities of the at least one radio access network without going outside the at least one radio access network. Transmitting the data includes connecting, at a node of the radio access network, the uplink channel between the first terminal and the node and the downlink channel between the node and the second terminal.

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: To increase a data rate irrespective of whether the spatial correlation between channels is high or low, while ensuring compatibility with the LTE-scheme MIMO system, in a MIMO system in which a base station apparatus (eNode B) switches between SU-MIMO transmission and ZF MU-MIMO transmission based on feedback information from a mobile station apparatus (UE) to perform data transmission, the mobile station apparatus (UE) selects a PMI and an RI corresponding to an Hermitian transpose of a channel matrix indicative of channel characteristics, calculates a CQI from the PMI, and transmits the PMI, RI and CQI as feedback, and the base station apparatus (eNode B) calculates a first data rate of the case of performing SU-MIMO transmission and a second data rate of the case of performing ZF MU-MIMO transmission based on the PMI that is fed back, and selects a transmission scheme corresponding to a higher data rate between the first and second data rates.

Abstract: Provided are a radio relay station apparatus, a radio base station apparatus and a radio communication method capable of improving user throughput and increasing the capacity in type II relay. The radio communication method of the present invention is characterized by, in a radio relay station apparatus, measuring channel quality of relay links with use of sounding reference signals from mobile terminal apparatuses; and transmitting feedback information including measurement results of channel quality of the relay links to a radio base station apparatus via a backhaul link; in the radio base station apparatus, measuring channel quality of direct links with use of sounding reference signals from the mobile terminal apparatuses, subtracting a correction value from the measurement results of the radio relay station apparatus; and allocating radio resources to a mobile terminal apparatus based on measurement results of the channel quality of the direct links and subtraction results.

Abstract: In order to improve user throughout and increase the capacity in type II relay, a radio relay station apparatus according to the present invention has a channel quality information controlling section configured to measure channel quality of a mobile terminal apparatus, calculate a channel quality reduction value to reduce for the mobile terminal apparatus due to interference from other mobile terminal apparatuses, and select a predetermined mobile terminal apparatus from the other mobile terminal apparatuses; and a transmitting section configured to transmit information of the channel quality of the mobile terminal apparatus, information of the predetermined mobile terminal apparatus selected and the channel quality reduction value to a radio base station apparatus.

Abstract: A base station apparatus includes a transmit diversity setting unit configured to set a transmit diversity mode to be applied to a user equipment terminal; a reception quality calculating unit configured to determine reception quality corresponding to the transmit diversity mode based on the transmit diversity mode set by the transmit diversity setting unit; a scheduling unit configured to determine a user equipment terminal to which a radio resource is to be allocated based on the reception quality determined by the reception quality calculating unit; and a notifying unit configured to notify the user equipment terminal to which the radio resource is allocated as determined by the scheduling unit of the transmit diversity mode to be applied.

Abstract: A base station for a mobile communication system includes a speed detecting unit configured to detect the moving speed of a user device based on a signal received from the user device and indicating the moving speed; and a determining unit configured to select, based on the moving speed detected by the speed detecting unit, a wideband channel quality indicator indicating reception quality of an entire system frequency band allocated to the mobile communication system, or a combination of the wideband channel quality indicator and one or more channel quality indicators of subbands in the system frequency band as channel quality information that needs to be reported from the user device to the base station.

Abstract: The present invention makes it possible to feed back PMIs that are required to generate precoding weights, while securing improvement of throughput performance, in downlink MIMO transmission using a plurality of transmitting antennas. With the present invention, in a mode to include a PTI (Precoder Type Indicator) in a PUCCH and feedback the PTI to a radio base station apparatus for downlink MIMO transmission using a plurality of transmitting antennas, the transmission cycle of feedback information corresponding to report 2 and report 3 when the value of the PTI is 0 are made different from the transmission cycle of feedback information corresponding to report 2 and report 3 when PTI=1 and the former feedback information and the latter feedback information are multiplexed, and the multiplexed signal is transmitted to the radio base station apparatus by the PUCCH.

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: 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: 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.