Abstract: A communication apparatus for use in a radio communication system, including: a reception unit configured to receive, from another communication apparatus, coded information to which a predetermined identifier is applied, decode the coded information to obtain a predetermined number of sequences that are candidates of a final decoding result, and perform a check by an error detection code using a plurality of identifiers for each of the predetermined number of sequences; and a sequence selection unit configured, if the check by the error detection code succeeds in a plurality of sequences by the reception unit, to select a sequence of the highest likelihood from the plurality of sequences as the final decoding result.

Abstract: A base station apparatus is used in a mobile communication system in which at least a shared data channel is transmitted by an orthogonal modulation scheme using an I-channel and a Q-channel. The base station apparatus includes a providing unit providing Acknowledgement/Non-Acknowledgement information indicating whether retransmission of a signal received in uplink is required; a mapping unit mapping a number of multiplexed users of the Acknowledgement/Non-Acknowledgement information to the I-channel or the Q-channel based on a predetermined mapping table; and a reporting unit reporting the Acknowledgement/Non-Acknowledgement information to the respective users. The mapping table indicates that, when the number of the multiplexed users is equal to or less than a predetermined number, the Acknowledgement/Non-Acknowledgement information is associated with the I-channel or the Q-channel, and otherwise, the Acknowledgement/Non-Acknowledgement information is associated with the I-channel and the Q-channel.

Abstract: To provide a radio communication method for enabling a control signal to be received with high quality and high efficiency, in the case of using spatial multiplexing transmission in data signals to transmit, and also transmitting the control signal in the same sub-frame, in the radio communication method of the invention, a mobile terminal apparatus receives a downlink signal including precoding information, separates a data signal and a control signal to assign to different radio resources, and performs MIMO-transmission on a signal of each transmission layer based on the precoding information, and a radio base station apparatus receives an uplink signal including the data signal and the control signal subjected to MIMO transmission, divides the uplink signal into data signals for each transmission layer, and reproduces the control signal from the uplink signal.

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: The present invention is designed to provide a radio base station apparatus, a mobile terminal apparatus, a radio communication system and a radio communication method which can cope with an increased number of users. A radio base station apparatus is provided with: a signal generating section that generates a first downlink control signal and a second downlink control signal for a mobile terminal apparatus; a first multiplexing section that multiplexes the first downlink control signal on a control region up to a predetermined number of symbols from the top of a subframe; a second multiplexing section that frequency-division-multiplexes the second downlink control signal on radio resources from the next symbol in the control region to the last symbol of the subframe; and a transmission section that transmits the first downlink control signal multiplexed on the control region and the second downlink control signal multiplexed on the radio resources.

Abstract: The present invention provides a base station apparatus, a mobile terminal apparatus and a communication control method which can improve the accuracy of channel quality estimation. A communication control method includes the steps of: allocating a CSI-RS (Channel State Information-Reference Signal), which is a reference signal for downlink channel estimation, in resources for the CSI-RS that are defined for CSI-RS transmission; setting muting resources in the resources for the CSI-RS; and reporting parameters to specify the CSI-RS, including at least a transmitting subframe cycle, a subframe offset and transmission power, to a mobile terminal apparatus.

Abstract: A radio communication system, a radio base station apparatus and a retransmission control method are disclosed. The retransmission control method is a retransmission control method in a radio communication system which has a first radio base station apparatus and a second radio base station apparatus that carry out coordinated multiple-point transmission with respect to a user terminal, and in which coordinated multiple-point transmission is applicable. With this retransmission control method, the first radio base station apparatus and the second radio base station apparatus execute retransmission control for downlink signals received in the user terminal, on a shared basis between the radio base station apparatuses. One radio base station apparatus of the first radio base station apparatus and the second radio base station apparatus sends a report to the user terminal to the effect that shared retransmission control is executed.

Abstract: In order to prevent any increase in number of blind detections and make efficient use of radio resources even when a format of downlink control information is changed in accordance with a communication environment, the present invention provides a radio communication method for generating control information by using a predetermined DCI format out of a plurality of DCI formats including a first DCI format having an uplink scheduling grant and a second DCI format having downlink scheduling assignment. When the first DCI format is extended in size, the second DCI format is added with an information field so as to have the same size as the extended first DCI format, and information to extend an existing function of the second DCI format and/or information to add a new function is added to the information field thereby to generate the control information.

Abstract: A base station apparatus capable of transmitting a downlink transmission frame at transmission timing different from another base station apparatus is provided. The base station apparatus includes a blank resource setting section that sets, as a blank resource, a resource corresponding to a downlink control channel included in a downlink transmission frame transmitted from the other base station apparatus, a user data assigning section that assigns user data to the downlink transmission frame while avoiding the blank resource, and a transmission section that transmits the downlink transmission frame assigned the user data to a mobile terminal apparatus.

Abstract: A radio communication system, a radio base station apparatus and a retransmission control method is provided that can realize a highly efficient retransmission control method in a CoMP environment. The retransmission control method is a retransmission control method in a radio communication system which has a first and second radio base station apparatus that carry out coordinated multiple-point transmission with respect to a user terminal, and in which coordinated multiple-point transmission is applicable, and, with this retransmission control method, the first radio base station apparatus and the second radio base station apparatus execute retransmission control for downlink signals received in the user terminal, on a shared basis between the radio base station apparatuses, and one radio base station apparatus of the first radio base station apparatus and the second radio base station apparatus sends a report to the user terminal to the effect that shared retransmission control is executed.

Abstract: A method to reduce interference between a macro cell and a small cell in a radio communication system in which the macro cell and the small cell are allocated to overlap at least in part is disclosed. The interference reduction method includes the steps in which a small base station transmits macro cell identification information that identifies the macro cell, to a user terminal in a small cell, allocates a downlink control signal for the user terminal to a radio resource unit having a different index number from that of a radio resource unit where a downlink control signal to be transmitted from the macro base station is allocated, and interleaves the downlink control signal for the user terminal using an interleaving pattern that is generated based on the macro cell identification information and that is the same as an interleaving pattern used in macro base station.

Abstract: In order to reduce radio resources allocated to PDCCHs and improve the data rate even when a plurality of component carriers are aggregated into a wide band, the present invention provides a base station apparatus having: a downlink control information generation section (306) configured to generate downlink control information (DCI) to demodulate PDSCHs that are sent independently in respective component carriers (CCs) allocated to a user terminal; and a transmitting section configured to transmit a PDCCH containing the downlink control information (DCI). The downlink control information (DCI) generated by the downlink control information generation section (306) is added with identification information (CIF) that is used to demodulate the PDSCHs assigned to the component carriers and is capable of identifying each of the component carriers.

Abstract: The present invention is designed to report transmit power information of each subframe adequately when a plurality of transmit power are set in a plurality of subframes constituting radio frames. A radio base station performs the steps of setting at least three or more kinds of varying transmit power in a plurality of subframes constituting a radio frame, and also determining a power ratio between a reference signal and a shared data channel signal in each subframe, generating bitmap information that represents a type pattern of transmit power set in the plurality of subframes, reporting the bitmap information and the power ratio to a user terminal and/or another radio base station, and generating the bitmap information with reference to a table in which the power ratio of each subframe and identifiers are associated with each other.

Abstract: The present invention is designed to maintain reduced interference in a layered network like a HetNet and improve the overall system throughput performance. A radio base station apparatus has a normal/ABS pattern determining section (2041) that determines a power ratio pattern that shows the power ratio between a reference signal (CRS) and a shared data channel signal (PDSCH) in each subframe, and a transmitting/receiving section (203) that transmits identification information for identifying the power ratio of each subframe in accordance with the determined power ratio pattern.

Abstract: A transmission apparatus is provided with radio resource assignment means that assigns radio resources to each physical channel according to a type of the physical channel; and transmission means that transmits information to be transmitted by each physical channel using the assigned radio resources.

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: In order to transmit a paging to a user terminal with high quality, transmit a CSI-RS effectively and perform UL HARQ efficiently in HetNet, the present invention provides a radio communication method having the steps of: a micro base station which is arranged in a macro cell and forms a smaller micro cell than the macro cell, transmitting, to a user terminal, a signal having a CSI-RS subframe including a CSI-RS and a paging subframe including modification notification information indicating modification in system information and a control signal indicating not to measure a CSI-RS when the CSI-RS subframe and the paging subframe collide with each other; and the user terminal determining a CSI-RS subframe to measure the CSI-RS based on the control signal when the CSI-RS subframe and the paging subframe collide with each other.

Abstract: To improve the frequency diversity effect and enhance reception quality characteristics in a mobile terminal apparatus even when the system bandwidth is extended, provided are a base station apparatus which maps transmission data to each user to a single or plurality of group bands among group bands configured by dividing a system band into a plurality of bands, and transmits the mapped transmission data on downlink, and a mobile terminal apparatus which receives the transmission data mapped to the group bands and demaps the transmission data.

Abstract: A base station apparatus is used in a mobile communication system in which at least a shared data channel is transmitted by an orthogonal modulation scheme using an I-channel and a Q-channel. The base station apparatus includes a providing unit providing Acknowledgement/Non-Acknowledgement information indicating whether retransmission of a signal received in uplink is required; a mapping unit mapping a number of multiplexed users of the Acknowledgement/Non-Acknowledgement information to the I-channel or the Q-channel based on a predetermined mapping table; and a reporting unit reporting the Acknowledgement/Non-Acknowledgement information to the respective users. The mapping table indicates that, when the number of the multiplexed users is equal to or less than a predetermined number, the Acknowledgement/Non-Acknowledgement information is associated with the I-channel or the Q-channel, and otherwise, the Acknowledgement/Non-Acknowledgement information is associated with the I-channel and the Q-channel.

Abstract: The present invention is designed to provide a radio base station apparatus, a mobile terminal apparatus, a radio communication system and a radio communication method which can cope with an increased number of users. A radio base station apparatus is provided with: a signal generating section that generates a first downlink control signal and a second downlink control signal for a mobile terminal apparatus; a first multiplexing section that multiplexes the first downlink control signal on a control region up to a predetermined number of symbols from the top of a subframe; a second multiplexing section that frequency-division-multiplexes the second downlink control signal on radio resources from the next symbol in the control region to the last symbol of the subframe; and a transmission section that transmits the first downlink control signal multiplexed on the control region and the second downlink control signal multiplexed on the radio resources.