Abstract: A user device includes a receiver configured to receive information indicating a ratio between a downlink data signal transmission power for an OFDM (orthogonal frequency division multiplexing) symbol in which a CRS (cell-specific reference signal) is not arranged and a downlink data signal transmission power for an OFDM symbol in which a CRS is arranged; and a controller configured to calculate a downlink data signal transmission power based on the information.

Abstract: To reduce a reception processing load, while obtaining gain of Non-Orthogonal Multiple Access (NOMA), in the case of transmitting a downlink signal using the NOMA scheme, a user terminal according to one aspect of the present invention is provided with a transmission section that transmits a plurality of precoding matrix indicators (PMIs) to a radio base station, and a reception section that receives, from the radio base station, a downlink signal that is non-orthogonally multiplexed with a downlink signal to another user terminal determined based on the plurality of PMIs and that is multiplied by the same precoding matrix as that of the downlink signal to another user terminal.

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: 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: 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: An uplink interference reduction method executed in a radio communication system which includes a connected base station, and an interference base station to which an interference user apparatus transmitting an interference signal with respect to the connected base station is connected, includes control information transmission step, transmitting to the connected base station by the interference base station, control information used for reducing the interference signal at the connected base station, and interference reduction step reducing, by the connected base station, the interference signal using the control information, to acquire a desired signal transmitted from a user apparatus that is connected to the connected base station.

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: 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 base station, according to received qualities at user devices, allocates a downlink transmission power to each user device. The base station transmits a mixed data signal in which data signals mutually not orthogonal and each addressed to a corresponding user device are mixed. Control signals are transmitted to user devices to enable each user device to decode a data signal addressed to the user device using a control signal corresponding to the user device. Each control signal is scrambled by the identifier of the corresponding user device. A control signal for a first user device to which a first data signal is addressed includes information indicating the identifier of a second user device to which a second data signal mixed with the first data signal is addressed. The first user device is thus enabled to descramble a control signal for the second user device.

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: 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: From a base station, a user equipment receives a mixed data signal transmitted in a format in which multiple data signals are transmitted with different downlink transmission powers such that the multiple data signals are not orthogonal to each other, multiple control signals corresponding to multiple user equipments, and information indicating an identifier of another user equipment. The user equipment determines an aggregation level of the subject user equipment. The user equipment uses the identifier of the other user equipment to attempt descrambling of one control signal among multiple control signals corresponding to an aggregation level higher than or equal to the aggregation level of the user equipment, and if the descrambling is successful, the user equipment uses the control signal to demodulate the non-orthogonal data signal.

Abstract: A base station allocates downlink transmission powers to user equipments according to the reception qualities of the user equipments. The base station transmits a mixed data signal in which multiple data signals that are addressed to multiple user equipments and are not orthogonal to each other are mixed, and transmits multiple control signals to the multiple user equipments such that each user equipment can decode the data signal addressed to that user equipment using the control signal corresponding to that user equipment. Each control signal is scrambled using the identifier of the user equipment corresponding to that control signal. With a period longer than the transmission period for the control signal, the base station notifies the multiple user equipments of identifier information indicating multiple identifiers, and thus the user equipment can descramble a control signal for another user equipment to which an interference data signal with a higher transmission power is addressed.

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 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: 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.