Abstract: To provide a radio base station apparatus and radio communication method capable of performing radio communications using downlink reference signal structures suitable for antenna virtualization, a radio base station apparatus (200) has a plurality of transmission antennas, generates CRSs used in demodulation of at least downlink control information, CQI-RSs generated for each of the transmission antennas used in measurement of channel quality, and DM-RSs generated for each stream used in demodulation of downlink transmission data, and multiplexes the CRSs, CQI-RSs and DM-RSs into a same transmission time unit to transmit from each of the antennas.

Abstract: A user apparatus is disclosed herein including a resource state detection unit configured to detect a state of a resource in a set of resources that can be used for device-to-device communication. The user apparatus further includes a control unit configured, when the state detected by the resource state detection unit does not satisfy a predetermined condition, to set the user apparatus to be in a state in which the user apparatus does not perform transmission of a device-to-device communication signal for a predetermined period. Additionally, the user apparatus also includes a transmission unit configured, when the user apparatus performs transmission of a device-to-device communication signal, to select a resource from among a set of resources, and to transmit a device-to-device communication signal using the selected resource.

Abstract: The present invention provides a base station apparatus, a mobile terminal apparatus and a communication control method that can adequately allocate resources of response signals for retransmission for spatially-multiplexed signals respectively corresponding to a plurality of layers via the uplink and that support next-generation mobile communication systems. Discloses is a configuration to receive signals in which a plurality of layers are spatially-multiplexed on the uplink from a mobile terminal apparatus (10), generate HARQ ACK/NACK for signals received in the layers on the uplink, and allocate HARQ ACK/NACK for transport blocks associated with the layers, to PHICH resources, using the offset values that are fixedly defined in advance with the mobile terminal apparatus (10) for every uplink layer.

Abstract: A user apparatus configured to perform transmission of a discovery signal by radio, including: means that determines a resource group pattern to be used by the user apparatus based on information transmitted from a base station, and determines a resource group including one discovery resource or a plurality of discovery resources that can be used for transmitting the discovery signal from among one resource group or a plurality of resource groups included in the resource group pattern; and means that selects a discovery resource to be used for transmitting the discovery signal from among the determined resource group.

Abstract: In the present disclosure, 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. The channel estimating apparatus for MUI signals has: a user type determining circuit that determines whether a UE apparatus corresponding to an own station belongs to a first type user or a second type user and determines 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 channel estimating circuit that performs channel estimation of a multi-user interference signal based on the determined demodulation information to use in channel estimation of MUI signals. With this structure, it is possible to improve channel estimation accuracy and further to improve the performance of data reception and user and cell throughputs.

Abstract: A base station configured to communicate with a user apparatus having a function for performing device-to-device communication by radio, including: an information transmission unit configured to transmit mapping information, to the user apparatus, in which service identification information on device-to-device communication is associated with a service type; an information reception unit configured to receive, from the user apparatus, service identification information corresponding to a service type of the user apparatus; and a resource assignment process unit configured to determine resource assignment used for device-to-device communication for each service based on the service identification information received from the user apparatus, and to transmit information indicating the resource assignment to the user apparatus.

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: A user apparatus having a function for performing device-to-device communication by radio, including: a resource state detection unit configured to detect a state of each resource in a set of resources that can be used for device-to-device communication; a backoff control unit configured, when the state detected by the resource state detection unit satisfies a predetermined condition, to set the user apparatus to be in a backoff state in which the user apparatus does not perform transmission of a discovery signal for a predetermined period; and a discovery signal transmission unit configured, when the user apparatus is not in the backoff state, to select a resource from among the set of resources, and to transmit a discovery signal using the selected resource.

Abstract: In a radio relay station, the channel quality of relay links is measured with the use of sounding reference signals from mobile terminals. Feedback information including the measurement results of the channel quality of the relay links is transmitted to a radio base station via a backhaul link. In the radio base station, the channel quality of the direct links is measured with the use of sounding reference signals from the mobile terminals. A correction value from the measurement results of the channel quality from the radio relay station is subtracted. Radio resources are allocated to a mobile terminal based on the measurement results of the channel quality of the direct links and the subtraction results.

Abstract: To provide a radio base station apparatus and radio communication method capable of performing radio communications using downlink reference signal structures suitable for antenna virtualization, a radio base station apparatus (200) has a plurality of transmission antennas, generates CRSs used in demodulation of at least downlink control information, CQI-RSs generated for each of the transmission antennas used in measurement of channel quality, and DM-RSs generated for each stream used in demodulation of downlink transmission data, and multiplexes the CRSs, CQI-RSs and DM-RSs into a same transmission time unit to transmit from each of the antennas.

Abstract: To use CSI feedback information capable of sufficiently supporting MU-MIMO transmission and CoMP transmission in LTE-A systems, in a radio communication method of the invention, a radio base station apparatus (200) generates downlink transmission data including a report mode corresponding to a bandwidth to perform feedback of feedback information including channel quality information and spatial channel information, and an extension level of the feedback information, and multiplexes the downlink transmission data and a reference signal for feedback information to transmit to a mobile terminal apparatus (100), and the mobile terminal apparatus (100) receives a downlink signal including the report mode and the extension level, and generates feedback information associated with the report mode and the extension level to transmit to the radio base station apparatus (200).

Abstract: A user apparatus configured to perform transmission of a discovery signal by radio, including: means that determines a resource group pattern to be used by the user apparatus based on information transmitted from a base station, and determines a resource group including one discovery resource or a plurality of discovery resources that can be used for transmitting the discovery signal from among one resource group or a plurality of resource groups included in the resource group pattern; and means that selects a discovery resource to be used for transmitting the discovery signal from among the determined resource group.

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: 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: 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: A user apparatus in a multi input multi output (MIMO) mobile communications system using pre-encoding is disclosed. The user apparatus includes a PMI generator which generates a pre-encoding matrix indicator (PMI) which indicates a pre-encoding matrix to be used by a base station; a transmitter which feeds back the PMI to the base station; and a receiver which receives a signal from the base station, wherein the signal received at the receiver includes information on whether it is according to PMI information fed back from the user apparatus after a predetermined elapsed time from a timing at which the PMI information is fed back from the user apparatus.

Abstract: A base station includes a receiving unit configured to receive a UE capability regarding a bandwidth from a mobile station; and a specifying unit configured to specify, among plural basic frequency blocks included in a system band, one or more basic frequency blocks to be used by the mobile station based on the UE capability.

Abstract: Provided is a downlink reference signal structure suitable for increase in number of transmission layers. A radio base station device (20) has a plurality of transmission antennas; a orthogonal RS sequence generator (22) for generating orthogonal reference signals based on a two-dimensional orthogonal code, the orthogonal reference signals being orthogonalized between downlink reference signals adjacent in two-dimensional directions of frequency direction and time direction to each other in one transmission layer and being orthogonalized in different transmission layers assigned to one radio resource; a multiplexer (23) for multiplexing transmission data and the orthogonal reference signals in the one transmission layer; and a transmitter for transmitting a transmission signal obtained by multiplexing the transmission data and the orthogonal reference signals, via the transmission antenna in transmission layers simultaneously.

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: To provide a radio base station apparatus and radio communication method capable of performing radio communications using downlink reference signal structures suitable for antenna virtualization, a radio base station apparatus (200) has a plurality of transmission antennas, generates CRSs used in demodulation of at least downlink control information, CQI-RSs generated for each of the transmission antennas used in measurement of channel quality, and DM-RSs generated for each stream used in demodulation of downlink transmission data, and multiplexes the CRSs, CQI-RSs and DM-RSs into a same transmission time unit to transmit from each of the antennas.