Abstract: The present invention is designed to reduce interference against uplink signals of a user terminal connected to low transmission power base station, in a heterogeneous network. The radio communication method of the present invention includes, at the radio base station apparatus of the first cell having a predetermined cell radius, reporting, to a user terminal, information about radio resources in which an uplink signal of a user terminal connected to a macro base station and an uplink signal of a user terminal connected to a low transmission power base station of an LPN cell having a smaller radius than the cell radius of the macro cell, are made orthogonal to each other, and, at the user terminal, allocating the uplink signals to radio resources based on the radio resource information reported from the macro base station or the LPN, and transmitting the allocated uplink signals to the macro base station or the LPN.

Abstract: The present invention is designed to feed back channel state information, from which adequate received quality can be calculated, upon CoMP transmission.

Abstract: To provide a radio base station apparatus, a radio relay station apparatus and a resource allocation method each which perform resource division of a backhaul sub-frame more optimally and can improve a throughput of a system, in the case of relay transmission. The radio base station apparatus according to the present invention includes: a frequency bandwidth control section configured to control a frequency bandwidth in a backhaul sub-frame, based on the number of the backhaul sub-frames, the number of mobile terminal devices, and frequency utilization efficiency of a radio link; and a transmitting section configured to transmit the backhaul sub-frame with the frequency bandwidth controlled by the frequency bandwidth control section.

Abstract: The present invention is designed to enable a radio base station apparatus to adequately estimate a coordinated cell to cause interference upon CoMP transmission, and effectively execute CoMP transmission. A radio communication system, according to the present invention, includes a plurality of radio base station apparatuses, and a user terminal (UE) that is configured to be able to perform coordinated multiple point transmission/reception with the plurality of radio base station apparatuses, where the user terminal (UE) has a transmission section that transmits information to use to estimate a candidate cell to be an interference cell upon coordinated multiple point transmission, and the radio base station apparatus has an estimation section that estimates a candidate cell to be an interference cell upon coordinated multiple point transmission based on the information.

Abstract: The present invention is designed to reduce the increase in the amount of the calculation process in a mobile station and the amount of CSI feedback data, and also prevent the amount of overall system capacity from decreasing. This radio communication system (1) has a radio base station (200) which can form a plurality of beams that are vertically sectorized. The radio base station (200), using an array antenna (10), forms at least the first beam that is directed to the cell edge side and a second beam that is directed to the cell center side, in parallel. A mobile station (100) measures channel quality by extracting reference signals from each of the first beam and the second beam, generates a communication quality feedback signal including channel quality measured from at least one of the beams, and feeds this back to the radio base station (200) via the uplink.

Abstract: The present invention is designed to use frequency resources effectively, even in the situation where a plurality of mobile terminal apparatuses of varying capabilities coexist. A communication system, in which a mobile terminal apparatus (10) and a base station apparatus (20) communicate using a basic carrier and an extended carrier that is additionally allocated to the basic carrier, in which: the base station apparatus has a setting section (310) that sets, in the extended carrier, a subframe of a first carrier type which can be received in each of a plurality of mobile terminal apparatuses of varying capabilities and a subframe of a second carrier type which can be received in part of the plurality of mobile terminal apparatuses, and a transmission section (203) that transmits the basic carrier and the extended carrier to the mobile terminal apparatus, and the mobile terminal apparatus has a receiving section (103) that receives the basic carrier and the extended carrier from the base station apparatus.

Abstract: The present invention is designed to reduce the space to install antennas and still increase the system capacity despite the state of the distribution of user terminals in cells. According to the radio communication method of the present invention, a radio base station apparatus selects precoding vectors from a codebook that is set in advance to be uneven with respect to the direction of the arrangement of antenna elements, based on communication quality information of the user terminals in the cell, multiplies signals to supply to each antenna element by the selected precoding vectors, and transmits the signals multiplied by the precoding vectors to the user terminals, and the user terminal receives a signal from the radio base station apparatus, extracts a reference signal from the received signal and measures channel quality; and feeds back a communication quality feedback signal, including the measured channel quality, to the radio base station apparatus, via the uplink.

Abstract: The present invention is designed to provide a radio communication system which can control uplink transmission power adequately even in an HetNet environment.

Abstract: The present invention is designed to execute adequate signaling even when individual user terminals perform communication to support separate types of communication, in MIMO transmission to use antennas having varying antenna configurations depending on the type of communication. A radio base station (200) has an antenna that has varying antenna configurations between at least two types of communication and that can transmit signals to all areas which the radio base station covers, in an antenna configuration to support at least one communication type 1, allocates radio resources to a downlink signal including capacities of a user terminal and a signal type to match a communication type, multiplexes a plurality of reference signals to be used in each communication type on the same resource block, generates precoding weights which allow the antenna to form a number of beams to match the communication type, and multiplies a downlink signal to supply to the antenna by the generated precoding weights.

Abstract: A communication control device includes a parameter acquisition unit which acquires a first parameter determined on the basis of the number of mobile stations connected to the first cell or the number of mobile stations connected to the second cell, a parameter determination unit which changes the number of mobile stations connectable to the first cell or the number of mobile stations connectable to the second cell on the basis of the first parameter, and a parameter notification unit which notifies at least any one of the first base station and the second base station of the determined second parameter.

Abstract: An “extension carrier” is exchanged between radio base stations eNB adjacent to each other. A mobile communication method according to the present invention includes a step in which a radio base station eNB#1 notifies a nearby radio base station eNB#2 of the “extension carrier” when multiple carriers include the “extension carrier”. The multiple carriers include at least one “stand-alone-capable carrier”.

Abstract: The present invention is designed to apply CoMP transmission/reception flexibly in a system band that is formed with a plurality of fundamental frequency blocks, improve received quality in user terminals, and also widen the system band.

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.

Abstract: The present invention is designed to flexibly report aperiodic channel state information to a plurality of radio base station apparatuses to be coordinated, even when coordinated multiple-point (CoMP) transmission/reception is performed.

Abstract: The present invention is designed to minimize the increase of user terminal power consumption even when downlink control channels are extended.

Abstract: To enable a mobile terminal apparatus to correctly demodulate a data signal in the case of applying Coordinated Multi-Point transmission (CoMP), particularly, JP-CoMP, a radio communication method of the invention is characterized in that a radio base station apparatus generates information for demodulation of a data signal in a mobile terminal apparatus in applying Coordinated Multi-Point transmission, and transmits the information for demodulation to a mobile terminal apparatus that performs Coordinated Multi-Point reception, and that the mobile terminal apparatus receives the information for demodulation of a data signal, and demodulates the data signal subjected to Coordinated Multi-Point reception using the information for demodulation.

Abstract: To partially suppress interference to control channels of a pico-cell from a base station apparatus of a macro-cell and enable assignment of user data to a subframe besides the same subframe using a part of control channels with interference suppressed thereto, a base station apparatus disposed in a second system having a system band comprised of a plurality of component carriers for sharing at least a part of a frequency band with a first system having a macro-cell (C2) and covering a pico-cell (C1) is configured to generate a carrier indicator for indicating another component carrier to which user data is assigned besides the same component carrier on a control channel of the component carrier, while indicating another subframe to which user data is assigned besides the same subframe on the downlink control channel.

Abstract: To provide a radio base station apparatus that enables the effect of improving usage efficiency of radio resources to be exerted sufficiently also in the case where the number of user terminals multiplexed into the same radio resources further increases, the radio base station apparatus performs communications using a first resource region for a downlink control channel subjected to time division, and a second resource region for a downlink data channel, and is characterized by being provided with generation sections (307, 308) that generate a first notification signal for notifying of the number of OFDM symbols of the first resource region, and a second notification signal for notifying of a starting position in the time domain of a third resource region obtained by performing frequency division on a part of the second resource region, and a multiplexing section (312) that multiplexes the first notification signal into the first resource region, and the second notification signal into the third resource regi

Abstract: To provide a user terminal, radio base station apparatus, radio communication system and radio communication method that support increases in the number of users, a user terminal is provided with a reception section that receives a downlink control signal multiplexed into radio resources from the starting OFDM symbol to a predetermined OFDM symbol in a subframe, and a downlink control signal subjected to frequency division multiplexing with a downlink data signal into radio resources after the predetermined OFDM symbol, a retransmission check section that performs a retransmission check on the downlink data signal based on the downlink control signal subjected to frequency division multiplexing to output a retransmission response signal, and a selection section that selects a radio resource of an uplink control channel used in transmission of the retransmission response signal.

Abstract: The present invention is designed such that it is possible to optimize the effect of improving the efficiency of use of radio resources even when the number of user terminals to be multiplexed over the same radio resources is further increased. A user terminal performs downlink communication with a radio base station using a PDCCH resource region and a PDSCH resource region. The user terminal detects the starting position of the radio resources where the PDSCH and the PDCCH are frequency-division-multiplexed in the PDSCH resource region in the time direction, and receives the PDCCH that is frequency-division-multiplexed over the radio resources starting from the detected starting position.