Abstract: The present invention is designed to expand the coverage of reference signals in small cells that are arranged to overlap a macro cell, and, furthermore, reduce the interference between the small cells and improve the received quality of the reference signals in user terminals. The radio communication method of the present invention provides a radio communication method in a radio base station forming a small cell that is placed to overlap a macro cell, and includes the steps of generating a reference signal for measuring received quality, in a first transmission period in which beamforming is not executed, transmitting the reference signal in a narrower transmission bandwidth and with greater transmission power than in a second transmission period in which beamforming is executed, and allocating the reference signal to a band associated with information that is specific to each radio base station forming a small cell, and transmitting the reference signal.

Abstract: In switching a radio base station (SeNB) from a radio base station (SeNB#1) to a radio base station (SeNB#2) in an “Inter-node UP aggregation”, the occurrence of transmission delay of downlink data to a mobile station (UE) is avoided. A mobile communication method according to the present invention includes: stopping, by the radio base station (SeNB#1), scheduling of downlink data to the mobile station (UE), and sending an “SeNB change command” to the mobile station (UE), when receiving an “SeNB change request ack” from the radio base station (SeNB#2); notifying, by the mobile station (UE), a radio base station (MeNB) of at least one of already received downlink data and unreceived downlink data; and resending, by the radio base station (MeNB), the mobile station the downlink data that is not received by the mobile station (UE) in response to the notification.

Abstract: In switching a radio base station (SeNB) from a radio base station (SeNB#1) to a radio base station (SeNB#2) in an “Inter-node UP aggregation”, forwarding of new downlink data destined for a mobile station (UE) from a radio base station (MeNB) to the radio base station (SeNB#2) is quickly started. A mobile communication method according to the present invention includes: sending, by the mobile station UE, the radio base station (MeNB) a “New data delivery request” that requests forwarding of new downlink data destined for the mobile station (UE) to the radio base station (SeNB#2) , in response to an “SeNB change command”; and forwarding, by the radio base station MeNB, the new downlink data destined for the mobile station (UE) to the radio base station (SeNB#2) , in response to the “New data delivery request”.

Abstract: The present invention is designed to adequately control small cells (small base stations) on/off in a structure where small cells and macro cells are arranged to overlap each other. A base station forms a macro cell, which is arranged to overlap a small cell, controls on/off of a small base station forming the small cell, and has a reporting section that reports, to the small base station, information related to a UL signal transmitted from a user terminal, and a control section that controls transmission of a DL signal from the small base station based on information that is reported from the small base station having detected the UL signal.

Abstract: The present invention is designed to improve the received quality of reference signals in user terminals, in small cells that are placed to overlap a macro cell. The reference signal transmission method according to the present invention is a reference signal transmission method in a radio base station that forms a small cell, which is placed to overlap a macro cell, and that has a plurality of antenna ports, and includes the steps of generating a plurality of reference signals that vary per antenna port, and in a reference signal transmission period in which beamforming is not executed, transmitting the plurality of reference signals in a transmission bandwidth that is narrower than in a second transmission period in which beamforming is executed, the reference signals of each antenna port are spread in at least one of the time direction and the frequency direction and transmitted.

Abstract: A radio base station apparatus has a multiplication section that multiplies downlink control information allocated to an extended downlink control channel resource region in a resource block, by a user terminal-specific weight; and a reporting section that reports one group, among a plurality of groups that are configured by selecting different antenna ports from a plurality of antenna ports corresponding to the number of transmission layers of a demodulation reference signal, to the user terminal, and in each group, extended downlink control channel resource regions in the resource block and antenna ports to constitute the group are associated with each other; and the multiplication section multiplies a demodulation reference signal corresponding to an antenna port in the one group that is associated with the extended downlink control channel resource regions where the downlink control information is allocated, by the weight.

Abstract: A user device receives, from a base station, a radio signal in which non-orthogonal signals are mixed. The user device recognizes, based on information transmitted from the base station, a parameter associated with the location of the user device. When the user device is at the edge of the cell area of the base station, a demodulator of the user device demodulates, as a signal directed to the user device, the radio signal in which an interference signal component has been suppressed by an interference rejection combining processor of the user device and a non-orthogonal signal canceller of the user device does not operate.

Abstract: To optimize operation of a mobile terminal apparatus when a Half-duplex FDD scheme is applied, the mobile terminal apparatus performs radio communications with a base station apparatus by HD-FDD, and when transmission timing of an uplink signal and reception timing of a downlink signal overlaps each other, selectively performs transmission processing of the uplink signal and reception processing of the downlink signal, based on a priority relationship defined between the uplink signal and the downlink signal.

Abstract: The present invention is designed to realize link adaptation that is optimal for future radio communication systems. A radio base station is configured to select user terminals from user groups that are determined based on the channel gain of each user terminal, determine a user set to non-orthogonal-multiplex over an arbitrary radio resource, with transmission power that is allocated to each user group on a fixed basis, and transmit downlink signals to the user terminals of the user set, with the transmission power that is allocated to each user group.

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: To increase the number of CSI-RSs for interference measurement to improve interference measurement accuracy, a first reference signal for channel state measurement and a second reference signal for interference measurement are assigned to reference signal resources defined for transmission of the first reference signal, and a mobile terminal apparatus that supports both the first reference signal and the second reference signal is notified of pattern information to identify an assignment pattern of the first reference signal and the second reference signal. A second mobile terminal apparatus that supports the first reference signal and that does not support the second reference signal is notified of pattern information to identify an assignment pattern of the first reference signal, and of assignment information indicating that resources assigned the second reference signal are assigned a third reference signal of zero power for channel state measurement.

Abstract: The present invention is designed to increase the number of CSI-RSs for interference measurements and improve the accuracy of interference measurements. The first reference signal is allocated to a reference signal resource defined for transmission of the first reference signal, and also a second reference signal for interference measurement is allocated, the allocation patterns of the first reference signal and the second reference signal are implicitly reported to the first mobile terminal to apparatus that supports both the first reference signal and the second reference signal, and, in the first mobile terminal apparatus, interference is measured using both the first reference signal and the second reference signal or using the second reference signal alone, based on the implicitly-reported allocation patterns.

Abstract: The present invention is designed to realize non-orthogonal multiple access while reducing the decrease of throughput. A radio base station selects a predetermined decoding pattern, based on channel state information of a user terminal, from among a plurality of decoding patterns in which information regarding the order of decoding of the non-orthogonal multiple access signals and/or whether or not SIC (Successive Interference Cancellation) is applied is defined, and transmits information to represent the selected decoding pattern to the user terminal, and the user terminal receives the information to represent the decoding pattern, and cancels interference in accordance with the order of decoding and SIC based on the decoding pattern that is shown in the received information.

Abstract: The present invention is designed to measure interference with high accuracy, without changing the density of CSI-RSs, in a future system that does not reply on CRSs. A base station apparatus (20) allocates CSI-RS to CSI resources that are defined for CSI-RS transmission, changes arbitrary resources in the CSI-RS resources in resource block units or in resource block group units, and determines and reports to a mobile terminal apparatus (10) the resources to be muted, and the mobile terminal apparatus (10) is configured to measure interference using the muted resources.

Abstract: It is an object of the present invention to provide a reference signal transmitting method, a mobile terminal apparatus and a base station apparatus capable of reducing influences on a PDCCH even when performing transmission control over an aperiodic reference signal for measuring channel quality.

Abstract: The present invention is designed to effectively apply carrier aggregation and Coordinated Multiple Point (CoMP) transmission/reception in a system band that is formed with a plurality of fundamental frequency blocks. A radio communication system where carrier aggregation is applicable in the same frequency band, and, this radio communication system includes the first radio base station apparatus and a second radio base station apparatus that perform coordinated multiple point transmission to a user terminal using cells having the same frequency band, and the first radio base station apparatus and the second radio base station apparatus perform retransmission control for uplink signals from the user terminal on a shared basis, and perform mapping of downlink signals to radio resources separately.

Abstract: To enable a user terminal to determine a cell of a downlink signal also in a heterogeneous environment using the same cell identification information, and thereby enable reception accuracy to be maintained, a radio communication method of the invention is characterized in that a radio base station apparatus generates a reference signal sequence by using a pseudo random sequence including user specific information, and transmits the reference signal sequence to a user terminal, and that the user terminal performs signal processing using the reference signal sequence transmitted from the radio base station apparatus.

Abstract: The present invention is designed to provide a radio base station apparatus which can acquire CSI reports at appropriate times, and which can trigger CSI reports effectively. The radio base station apparatus of the present invention has: a PDCCH signal generating section (211) that generates a downlink allocation signal for receiving and decoding downlink transmission data, the downlink allocation signal including a report request bit for triggering reporting of channel information aperiodically; a transmission section that transmits a downlink signal including a downlink control channel where the downlink allocation signal is mapped; and a receiving section that receives an uplink signal which includes the reporting of channel information from a terminal triggered by the report request bit, via the uplink.

Abstract: To provide a radio base station apparatus, mobile terminal device and wireless communication method for transmitting and receiving downlink channel quality measurement reference signals in consideration of interference estimation of high accuracy, in a wireless communication method of the invention, a radio base station apparatus generates channel quality measurement reference signals, and maps the channel quality measurement reference signals to two adjacent symbols, and a mobile terminal device receives a downlink signal including the channel quality measurement reference signals mapped to two adjacent symbols, and performs interfering power estimation using the channel quality measurement reference signals mapped to two adjacent symbols.

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.