Abstract: Some OFDM symbols transmitted temporally continuously by a base station include data signals that are not orthogonal to each other and are directed to user devices. A reference signal is arranged in the OFDM symbols temporally intermittently. The base station determines, according to reception qualities at user devices, downlink data signal transmission powers for transmitting downlink data signals. The base station reduces a downlink data signal transmission power in an OFDM symbol in which the reference signal is arranged to be lower than a downlink data signal transmission power in an OFDM symbol in which the reference signal is not arranged. The base station determines a downlink reference signal transmission power to be higher than the downlink data signal transmission power of a data signal in the OFDM symbol in which the reference signal is not arranged.

Abstract: In a radio communication system including multiple mobile terminals and multiple radio base stations, the mobile terminal has a function of interference rejection combining. The radio base stations share downlink channel characteristics for mobile terminals connected to radio base stations. The radio base station gives weights to radio waves transmitted from multiple transmission antennas to perform in-phase addition of an interfering radio wave beam directed to a mobile terminal for which the desired radio base station is another radio base station to an interfering radio wave beam transmitted from yet another radio base station for limiting the number of interfering radio wave beams that arrive at the mobile terminal. The radio base station does not perform in-phase addition when the number of interfering radio wave beams of which interference can be suppressed by the mobile terminal is equal to or greater than the number of radio base stations that send interfering radio wave beams to the mobile terminal.

Abstract: A base station configured to communicate with a user apparatus in a radio communication system executing carrier aggregation, including: a reception unit configured to receive, from an interference base station, control information that is used for the user apparatus to reduce an interference signal from the interference base station for a component carrier used by the user apparatus; a determination unit configured to determine whether a connecting cell corresponding to the component carrier and an interference cell formed by the interference base station satisfy a predetermined condition; and a transmission unit configured, when the determination unit determines that the connecting cell and the interference cell satisfy the predetermined condition, to transmit the control information to the user apparatus.

Abstract: A user apparatus that is used in a radio communication system including a plurality of base stations, and that includes a function for performing interference reduction based on user assignment in an interference cell, including: interference pattern generation means that generates a plurality of interference patterns each of which is a combination of presence or absence of an interference signal in a given number of interference cells for the user apparatus; reception quality calculation means that calculates a reception quality after interference reduction for each of the plurality of interference patterns generated by the interference pattern generation means; and user assignment information estimation means that determines presence or absence of an interference signal in each interference cell corresponding to an interference pattern based on which the best reception quality is obtained in reception qualities calculated by the reception quality calculation means to be presence or absence of user assignmen

Abstract: A user apparatus for use in a radio communication system, including: an interference reduction process unit configured to reduce, from a received signal received by the user apparatus, an interference signal that becomes interference to a desired signal so as to obtain the desired signal; an interference reduction process execution determination unit configured to measure reception quality of the interference signal, and to determine whether to regard the interference signal as a target of interference reduction processing based on the reception quality, wherein the interference reduction process execution determination unit determines whether to regard the interference signal as the target of interference reduction processing by comparing a first indicator value of the interference signal that is estimated from the reception quality with a second indicator value that is used for transmission of the interference signal.

Abstract: The present invention is designed to perform CQI measurement for adjacent cells without making the processes in the user terminal UE complex. A base station apparatus (eNodeB #1) provided in the serving cell has features of acquiring, from a base station apparatus (eNodeB #2) provided in an adjacent cell, the cell ID of the adjacent cell, and the position and transmission power of the CSI-RS, as parameters related to the CSI-RS of the adjacent cell, generating a broadcast signal including the above parameters related to the CSI-RS, and transmitting the generated signal to the user terminal (UE).

Abstract: A user apparatus for use in a radio communication system, including: an successive interference cancelling reception unit configured to obtain a desired signal by successively canceling an interference signal that becomes interference to the desired signal from a received signal that the user apparatus receives; and an ordering determination unit configured to determine an order of interference signals to be successively canceled by the successive interference cancelling reception unit, wherein the ordering determination unit determines the order based on reception quality for each interference signal.

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: A user apparatus in a radio communication system including a plurality of base stations, including: a reception unit configured to receive, from a connecting base station, control information to be used for reducing an interference signal sent from an interference base station for the user apparatus; and an interference reducing unit configured to reduce the interference signal by using the control information to obtain a desired signal sent from the connecting base station, wherein the reception unit receives a part of the control information as a part of downlink control information that is transmitted by a downlink physical layer signaling channel from the connecting base station, and receives the other part of the control information by RRC signaling.

Abstract: A base station connected to a user apparatus in a radio communication system is provided. The base station includes a receiving unit configured to receive from an interference base station first control information which is used by the user apparatus for reducing an uplink interference signal from one or more cells formed by the interference base station or from another user apparatus, a generation unit configured to generate second control information based on one or more pieces of the first control information received from the interference base station, and a transmitting unit configured to transmit the second control information to the user apparatus by a downlink control signal.

Abstract: In a radio communication system in which a high-power base station and a low-power base station collaborate for inter-cell interference control, the downlink transmission power at the high-power base station is suitably controlled. The high-power base station executes wireless transmission to the user terminals using resources that are the same as resources used by the low-power radio base station. A transmission power controller of the radio base station uses a first downlink transmission power at first resources and uses a lower second downlink transmission power at second resources. The transmission power controller adjusts the second downlink transmission power in accordance with the number of user terminals capable of executing interference rejection combining, the downlink traffic amount for user terminals capable of executing interference rejection combining, or the number of downlink resource blocks allocated to user terminals capable of executing interference rejection combining.

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: To signal CSI-RS location indexes indicative of CSI-RS location positions in a resource block with high efficiency, a signaling method of CSI-RS is characterized by having the steps of locating a CSI-RS that is a reference signal for downlink channel estimation in resources for CSI-RS reserved to transmit the CSI-RS, generating a CSI-RS location index indicative of a location position of the CSI-RS located in the resources for CSI-RS, in the CSI-RS location index an index pattern varies corresponding to the number of CSI-RS ports so that an index pattern of the relatively low number of CSI-RS ports is a subset of an index pattern of the relatively high number of CSI-RS ports, and transmitting the generated CSI-RS location index to a mobile terminal apparatus.

Abstract: A radio communication system includes multiple radio base stations and multiple mobile communication terminals. Each mobile communication terminal measures a reception quality of radio waves from each radio base station. A first mobile communication terminal that can execute interference rejection combining offsets the reception quality value of radio waves from a second radio base station by using a first bias value. A second mobile communication terminal that cannot execute interference rejection combining offsets the reception quality value of radio waves from the second radio base station by using a second bias value that is lower than the first bias value. The first radio base station selects, as the radio access point for the mobile communication terminal, a radio base station corresponding to a reception quality value indicating a best reception quality among the first reception power value and the offset second reception power value.

Abstract: A user apparatus that is used in a radio communication system including a plurality of base stations, and that includes a function for performing interference reduction based on user assignment in an interference cell, including: interference pattern generation means that generates a plurality of interference patterns each of which is a combination of presence or absence of an interference signal in a given number of interference cells for the user apparatus; reception quality calculation means that calculates a reception quality after interference reduction for each of the plurality of interference patterns generated by the interference pattern generation means; and user assignment information estimation means that determines presence or absence of an interference signal in each interference cell corresponding to an interference pattern based on which the best reception quality is obtained in reception qualities calculated by the reception quality calculation means to be presence or absence of user assignmen

Abstract: A user apparatus in a radio communication system including a plurality of base stations, including a reception unit that receives, from a connecting base station, control information to be used for reducing a signal of a control channel, that causes interference, sent from an interference base station for the user apparatus, and an interference reducing unit that reduces the signal of the control channel that causes the interference by using the control information to obtain a desired signal sent from the connecting base station.

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 orthogonalization among transmission antennas, orthogonalization among cells, and interference estimation of high accuracy, in a wireless communication method of the invention, a radio base station apparatus generates channel quality measurement reference signals, performs randomization processing on the channel quality measurement reference signals to be mutually non-orthogonal among at least a part of cells, and orthogonalizes the channel quality measurement reference signals among transmission antennas to transmit to a mobile terminal device together with control information, and the mobile terminal device receives a downlink signal including the control information and the channel quality measurement reference signal, extracts the channel quality measurement reference signal using the control informatio

Abstract: A mobile communication terminal calculates an interference rejection combining reception weight matrix so as to reduce interference with a desired beam by another beam, in which the desired beam is a beam of radio waves transmitted from a desired base station. The mobile communication terminal estimates an interference and noise power expected when the IRC is implemented based on the interference rejection combining reception weight matrix and calculates a signal-to-interference-plus-noise ratio expected when the IRC is implemented based on the interference and noise power. The mobile communication terminal measures or calculates received signal qualities relative to radio waves received from a plurality of base stations, to compensate for the signal-to-interference-plus-noise ratio or the interference and noise power.

Abstract: A mobile communication terminal calculates an interference rejection combining reception weight matrix based on a vector representing a reference signal transmitted from a desired base station so as to reduce interference with a desired beam of radio waves. The mobile communication terminal estimates, from the interference rejection combining reception weight matrix and the reference signal, an all received power expected when an IRC is implemented, and estimates, from an interference rejection combining weight vector, a channel matrix, and a reference signal sequence, a desired reference signal power expected when an IRC is implemented. The mobile communication terminal subtracts the desired reference signal power from the all received power, thereby estimating an interference and noise power expected when an IRC is implemented, and calculates an SINR expected when an IRC is implemented from the estimated interference and noise power.

Abstract: A user apparatus, in a radio communication system including a plurality of base stations, including a reception unit configured to receive, from a connecting base station, control information to be used for reducing an interference signal sent from an interference base station for the user apparatus; and an interference reducing unit configured to reduce the interference signal by using the control information to obtain a desired signal sent from the connecting base station.