Abstract: A base station device includes: a control information generating section which generates control information specific to mobile station devices; a control information count indicator generating section which generates a control information count indicator indicating the number of pieces of generated control information of each mobile station device; and a transmitting section which transmits the control information count indicator and the control information. The mobile station device includes: a receiving section which receives a control information count indicator and control information transmitted from the base station device within a mobile station-specific search space selected based on a mobile station ID of the mobile station device; a control information count indicator detecting section which detects the control information indicator; and a control channel decoding section which decodes the control channel in response to the number of pieces of detected control information.

Abstract: A communication system which performs communication between a base station device configuring at least one cell and a mobile station device, wherein: the base station device includes: a synchronization signal generation unit which generates a synchronization signal corresponding to a cell identity for identifying a cell; and a transmission unit which generates a first transmission signal including the synchronization signal using a first parameter obtained from the cell identity, generates a second transmission signal excluding the synchronization signal using a second parameter obtained from a virtual cell identity different from the cell identity, transmits the first transmission signal using a first frequency band, and transmits the second transmission signal via a second frequency band different from the first frequency band.

Abstract: An EPDCCH is made up of an aggregation of one or more resources obtained by dividing one of PRB pairs. In a case where a total number of antenna ports for transmitting reference signals to be used to demodulate signals mapped to the EPDCCH is four, four resources obtained by dividing one of the PRB pairs correspond to the antenna ports of different numbers. In a case where a total number of antenna ports for transmitting reference signals to be used to demodulate signals mapped to the EPDCCH is two, two resources obtained by dividing one of the PRB pairs correspond to the antenna ports of different numbers. A mobile station apparatus includes a reception processor that demodulates, by using reference signals transmitted from the antenna ports corresponding to the resources used for the EPDCCH, signal mapped to the EPDCCH for which decoding and detection are performed.

Abstract: A terminal device includes a transmitter that transmits a random access preamble, a higher layer processor that configures, based on a higher layer signal, a first identity corresponding to a first component carrier group and a second identity corresponding to a second component carrier group; a counter that, in a case that two or more component carriers are configured for an uplink, counts a number of transmission of the random access preamble; and a medium access control (MAC) layer processor that indicates a random access problem to an upper layer in a case that the number exceeds a maximum number of transmission of the random access preamble on a master component carrier of the first component carrier group or a master component carrier of the second component carrier group.

Abstract: In a radio system which allocates resources using as units resource blocks which are formed by frequency components and time components, control information for mobile station devices, and identification information which is used to identify a format for a control information transmission channel which transmits the control information is transmitted from the base station device to the mobile station devices by means of the control information transmission channel.

Abstract: A user equipment (UE) receives using a PDCCH, downlink control information (DCI) including second information (SI), the DCI being used for scheduling of a PUSCH in one uplink component carrier. The UE transmits using the PUSCH, channel state information (CSI) for a first set of one or more downlink component carriers (DCCs) which is configured in a case that more than one DCC is configured and the DCI including the SI is received and a value of the field of the SI is a first value. The UE transmits using the PUSCH, the CSI for a second set of the one or more DCCs which is configured in a case that the more than one DCC is configured and the DCI including the SI is received and a value of the field of the SI is a second value, where the DCI is mapped on a UE specific search space.

Abstract: There are provided a base station, a terminal, a communications system, and a communications method which enable efficient transmission and reception of transmission data even in the case where the base station notifies the terminal of control information via an enhanced physical downlink control channel. A terminal configured to perform communication with a base station monitors a physical downlink control channel mapped to a physical downlink control channel region, and acquires higher-layer control information indicating a plurality of enhanced physical downlink control channel regions different from the physical downlink control channel region. In the case where the terminal has acquired the higher-layer control information, the terminal monitors an enhanced physical downlink control channel mapped to at least one region from among the plurality of enhanced physical downlink control channel regions, in place of the physical downlink control channel mapped to the physical downlink control channel region.

Abstract: In a radio communication system in which a base station and a terminal communicate with each other, the base station efficiently transmits control information to the terminal. The base station that communicates with the terminal using resource blocks, each of which is constituted by a prescribed time region and a prescribed frequency region, includes a terminal-specific control channel generation unit that generates terminal-specific control channels mapped in a terminal-specific control channel region constituted by a prescribed number of resource blocks and transmitted using the same antenna port as for terminal-specific reference signals, which are reference signals specific to the terminal.

Abstract: A mobile station apparatus, that communicates with a base station apparatus, includes a reception unit that receives a physical downlink shared channel and information indicating radio resources for transmission of a physical uplink shared channel associated with contention based procedure and a transmission unit that transmits Hybrid Automatic Repeat Request (HARQ) information in response to the physical downlink shared channel and the physical uplink shared channel. The transmission unit also transmits, in case that transmissions of the HARQ information and the physical uplink shared channel happen in a single subframe, either both of the HARQ information and the physical uplink shared channel or the physical uplink shared channel without the HARQ information in the single subframe on the basis of a configuration.

Abstract: In a system including at least one base station device, the base station device efficiently controls uplink signals. A mobile station device includes a path loss calculation unit 4051 configured to calculate path losses, each based on one of a plurality of types of reference signals received by a reception processing unit 401, a transmit power setting unit 4053 configured to set a desired transmit power for an uplink signal using the path losses calculated by the path loss calculation unit 4051, and a power headroom control unit 4055 configured to generate a power headroom using the desired transmit power set by the transmit power setting unit 4053, the power headroom being information concerning transmit power to spare, and configured to control transmission of the power headroom.

Abstract: In a terminal that communicates with a base station, in the case where a physical downlink control channel or an enhanced physical downlink control channel, which is associated with a physical downlink shared channel on a first cell, and an enhanced physical downlink control channel associated with a physical downlink shared channel on a second cell are detected, one physical uplink control channel resource is selected from a physical uplink control channel resource configured for the physical downlink shared channel on the first cell and a physical uplink control channel resource configured for the physical downlink shared channel on the second cell.

Abstract: A communication system comprises at least a base station device and a terminal device. The terminal device transmits a demodulation reference signal associated with a physical channel, receives a configuration of comb of the demodulation reference signal, and transmits the demodulation reference signal mapped based on the configuration of comb. The base station device transmits a configuration of comb of a demodulation reference signal related to a physical channel.

Abstract: A mobile station device and a base station device correctly communicate using E-PHICH. The mobile station device receives information indicating a subframe to be reserved for transmitting a HARQ feedback using an enhanced physical HARQ indicator channel, transmits a transport block by using a physical uplink shared channel, and if a time in which the HARQ feedback for the transmission of the transport block is received by using the enhanced physical HARQ indicator channel is a subframe excluding the subframe indicated by the information, when the HARQ feedback for the transmission of the transport block is received, the mobile station device sets a state variable managed by a HARQ process corresponding to the transport block to acknowledgement (ACK).

Abstract: In a mobile station that performs communication with a base station device via a plurality of cells, the plurality of cells are grouped into a first group constituted by cells having an uplink transmission timing that is the same as that of one primary cell and a second group constituted by one or more cells having an uplink transmission timing that is different from that of the primary cell. The uplink transmission timings are each managed using a corresponding transmission timing timer for each of the groups. In a case where a transmission timing timer for the first group has expired, the mobile station stops all uplink transmissions in the plurality of cells. In a case where a transmission timing timer for the second group has expired, the mobile station stops uplink transmissions in the cells constituting the second group for which the transmission timing timer has expired.

Abstract: A terminal device sets a first UL-DL configuration, sets a subframe for monitoring a physical downlink control channel accompanied with information indicating a second UL-DL configuration, monitors the physical control channel accompanied with information indicating the second UL-DL configuration in the set subframe during an active time based on a first subframe set as a downlink subframe or a subframe including a DwPTS based on the first UL-DL configuration, and monitors a physical downlink control channel accompanied with a C-RNTI in a second subframe set as a downlink subframe or a subframe including the DwPTS based on the second UL-DL configuration during the active time.

Abstract: A mobile station device includes: a management unit managing generation of uplink control information; a transmission power parameter setting unit setting a value of a parameter relevant to transmission power in accordance with the number of information bits of receipt acknowledgement and scheduling request, when the management unit generates the receipt acknowledgement which is uplink control information indicating positive or negative acknowledgement for downlink data and the scheduling request which is uplink control information indicating whether to request resource allocation; and a transmission processing unit controlling, by means of the parameter value set by the transmission power parameter setting unit, the transmission power for a physical uplink control channel used for transmitting a signal generated from the information bits of the receipt acknowledgement and the scheduling request, and transmitting the signal to a base station device using the physical uplink control channel with the controlled

Abstract: A communication system includes a terminal apparatus and a base station apparatus. The terminal apparatus communicates with a base station apparatus by carrier aggregation using a plurality of serving cells, where each of the plurality of serving cells has a different frequency. In addition, the terminal apparatus removes a measurement identity relevant to a serving cell of the plurality of serving cells based on that the serving cell was removed.

Abstract: Provided are a communication system, a base station apparatus, a mobile station apparatus, and a communication method for reducing interference between uncoordinated adjacent cells. The communication system of the present invention comprises a base station apparatus and a mobile station apparatus. The base station apparatus notifies the mobile station apparatus of a downlink control information format, the downlink control information format including resource allocation information that dictates switching of resource allocation of an uplink demodulation reference signal localized resource allocation and distributed resource allocation, and a frequency offset of the distributed resource allocation of the uplink demodulation reference signal specific to the mobile station apparatus.

Abstract: A user equipment (UE) receives using a PDCCH, downlink control information (DCI) including second information (SI), the DCI being used for scheduling of a PUSCH in one uplink component carrier. The UE transmits using the PUSCH, channel state information (CSI) for a first set of one or more downlink component carriers (DCCs) which is configured in a case that more than one DCC is configured and the DCI including the SI is received and a value of the field of the SI is a first value. The UE transmits using the PUSCH, the CSI for a second set of the one or more DCCs which is configured in a case that the more than one DCC is configured and the DCI including the SI is received and a value of the field of the SI is a second value, where the DCI is mapped on a UE specific search space.

Abstract: A mobile station apparatus receives a radio resource control signal including at least a first parameter POFFSET (0) and a second parameter POFFSET (1). The mobile station apparatus also transmits a first reference signal on a first antenna port and a second reference signal on a second antenna port. In addition, the mobile station apparatus sets a first transmit power for a transmission of the first reference signal based on at least the first parameter POFFSET (0), a maximum transmit power value, a path loss and a transmission power control command. The mobile station apparatus also sets a second transmit power for a transmission of the second reference signal based on at least the second parameter POFFSET (1), a maximum transmit power value, a path loss and a transmission power control command.