Abstract: A user apparatus is disclosed in a radio communication system that supports a D2D communication. The user apparatus includes a selector that selects a first resource for transmitting control information in a first carrier and a second resource for transmitting data in a second carrier, and a transmitter that transmits control information that includes information to specify the second resource using the first resource and to transmit data using the second resource. A base station is also disclosed in a radio communication system that supports a D2D communication. The base station includes a selector that allocates a first resource to transmit control information in a first carrier for the D2D communication and a second resource to transmit data in a second carrier for the D2D communication to a user apparatus, and a transmitter configured to transmit resource allocation information to indicate the first resource and the second resource.

Abstract: The present invention is designed so that PRACH transmission is carried out taking coverage enhancement into account. A radio communication terminal employs coverage enhancement and has a transmitting section that transmits a random access preamble by using a radio resource that is stipulated for the radio communication terminal employing coverage enhancement, and, in this radio communication terminal, one or a combination of the time, the frequency band and the sequence of the radio resource that is stipulated for the radio communication terminal employing coverage enhancement is different from that of a radio resource that is stipulated for a radio communication terminal not employing coverage enhancement.

Abstract: A user equipment in a wireless communication system in which communication is performed between a base station and a user equipment includes: a first reception unit that receives information on communication performed in each of a plurality of carriers from the base station; a selection unit that selects a carrier in which the user equipment has to receive signals among the plurality of carriers based on the information on communication performed in each of the plurality of carriers; and a second reception unit that receives predetermined communication in the carrier selected by the selection unit.

Abstract: A user apparatus in a radio communication system that supports D2D communications includes an acquisition unit configured to acquire, from a base station, transmission power information including a candidate transmission power value of a D2D signal, and a transmission unit configured to change transmission power at each of predetermined periods, based on the candidate transmission power value included in the transmission power information, for transmitting a D2D signal.

Abstract: A user equipment that communicates with a base station in a radio communication system including the base station and the user equipment includes: an acquisition unit that acquires downlink control information from a downlink control channel by using a part of an identifier used for identifying a channel and acquires a remaining part acquired by excluding the part from the identifier from a predetermined resource; and an identification unit that identifies the channel by using the identifier configured by the part and the remaining part acquired by the acquisition unit.

Abstract: A user apparatus is described that performs D2D communication by radio, including a signal reception unit configured to detect a signal addressed to the user apparatus by detecting an identifier of a physical layer of the user apparatus that is associated with an identifier of an upper layer of the user apparatus from a signal received by radio. The signal reception unit further detects data of the upper layer addressed to the user apparatus by using the identifier of the physical layer of the user apparatus as a part of the identifier of the upper layer of the user apparatus.

Abstract: A user apparatus according to an embodiment is provided in a wireless communication system in which D2D communications are supported. The user apparatus includes a resource allocation unit configured to allocate a resource for D2D control information to be transmitted at a transmission timing subsequent to a predetermined transmission timing; and a transmission unit configured to transmit resource reservation information including information indicating the resource for D2D control information.

Abstract: A user apparatus that performs D2D communication by radio includes a signal transmission unit configured to transmit a signal including a destination identifier of a physical layer associated with a destination identifier of an upper layer which is a layer higher than the physical layer; and a signal reception unit configured to detect a signal addressed to the user apparatus by detecting an identifier, of the physical layer of the user apparatus, that is associated with an identifier of the upper layer of the user apparatus from a signal received by radio.

Abstract: A user apparatus in a mobile communication system includes an allocation means that divides a message that includes control information and data into a plurality of partial messages, and allocates resources included in one or more resource pools to the plurality of partial messages; and a transmission means that transmits the plurality of partial messages using the resources allocated by the allocation means.

Abstract: A user apparatus in a radio communication system that supports D2D includes: an acquisition unit configured to acquire radio parameter information including a D2D radio parameter managed in a unit of a predetermined region including a plurality of cells from a base station; and a communication unit configured to transmit and receive a D2D signal using the D2D radio parameter in the predetermined region.

Abstract: The present invention is designed to adequately carry out uplink communication in unlicensed bands in a radio communication system (LAA) that runs LTE in unlicensed bands. A user terminal has a control section that controls the transmission and receipt of a signal in a first frequency carrier in which LBT (Listen Before Talk) is configured or in a second frequency carrier in which LBT is not configured, and the control section controls the step of receiving a random access response and subsequent steps in random access procedures to be performed in the second frequency carrier, and, furthermore, controls uplink transmission to be carried out in the first frequency carrier after random access is established.

Abstract: There is provided a user apparatus of a radio communication system supporting D2D communication, the user apparatus including a receiver configured to receive a first synchronization signal transmitted from a base station, a second synchronization signal transmitted from another user apparauts, or an external synchronization signal or external synchronization information transmitted from an external synchronization source; and a synchronization processor configured to execute synchronization using the first synchronization signal, the second synchronization signal, or the external synchronization signal or the external synchronization information received by the receiver; wherein, upon detecting that the user apparatus is outside a coverage area of the base station or outside an area in which the synchronization signal or the synchronization information can be received, the receiver is configured to receive the second synchronization signal by executing an initial search within a time window defined for monit

Abstract: The present invention is designed so that communication overhead pertaining to control signals is reduced in a communication system in which the bandwidth of a physical downlink shared channel is narrower than the system bandwidth. The radio base station of the present invention has a resource allocation section that allocates a physical downlink shared channel to a predetermined narrow band in a downlink system bandwidth, for a user terminal, and a downlink control information generating section that generates downlink control information to report to the user terminal, and the downlink control information generating section determines the size of a field pertaining to resource allocation information, included in downlink control information related to the physical downlink shared channel, based on the narrow band where the physical downlink shared channel is allocated.

Abstract: The present invention is designed to realize RACH traffic off-loading. A radio communication terminal communicates with a radio base station by using a carrier that is different from the connecting carrier and includes an unlicensed band, and has a transmission section that transmits a cross-carrier RACH in the carrier including the unlicensed band, and a receiving section that receive a random access response that is transmitted from the radio base station having received the cross-carrier RACH.

Abstract: A user equipment in a radio communication system supporting D2D communication includes a determination unit that receives a first region in a radio frame, which is commonly used for downlink communication and uplink communication with a base station and includes the first region to which a downlink pilot signal and a downlink control signal are to be mapped and a second region to which downlink user data or uplink data is to be mapped, to determine whether a D2D signal is transmittable using the second region; and a transmission unit that transmits the D2D signal using the second region in the radio frame where a D2D physical control channel and a D2D physical data channel are time-multiplexed when the determination unit determines that the D2D signal is transmittable.

Abstract: The present invention is designed to enable adequate feedback on the uplink even when CA and CoMP are employed between a plurality of radio base stations (inter-eNB CoMP/CA). A receiving section that receives downlink signals from a first radio base station that forms a first cell and a second radio base station that forms a second cell, a generating section that generates a feedback signal in response to the downlink signal from each radio base station, and a control section that assigns the feedback signal in response to the downlink signal from the first radio base station to an uplink control channel and/or an uplink shared channel on the first cell depending on whether or not there is a UL grant, and assigns the feedback signal in response to the downlink signal from the second radio base station to the uplink shared channel on the first cell or the second cell regardless of whether or not there is the UL grant, are provided in a user terminal.

Abstract: There is provided a user apparatus of a radio communication system supporting D2D communication, the user apparatus including a receiver configured to receive a signal of an external synchronization source, a synchronization signal transmitted from a base station, or a synchronization signal transmitted from another user apparatus; and a synchronization processor configured to execute, in accordance with priority information indicating priority order of signals used for synchronization, radio frame synchronization and frequency synchronization using any one of the signal of the external synchronization source, the synchronization signal transmitted from the base station, or the synchronization signal transmitted from the other user apparatus, which is received by the receiver.

Abstract: A user apparatus in a radio communication system that supports a Device to Device (D2D) communication is disclosed. The user apparatus includes a first transmission unit configured to transmit radio resource allocation information, in case of transmitting a Medium Access Control (MAC) Protocol Data Unit (PDU) of high priority, by using a specific subframe that is used for transmitting radio resource allocation information corresponding to a MAC PDU of high priority, from among radio resources allocated to a D2D control channel. A second transmission unit is configured to transmit the MAC PDU via a D2D data channel in accordance with the transmitted radio resource allocation information.

Abstract: User equipment of a mobile communication system supporting D2D includes a reservation unit that transmits reservation information including reservation resource identification information corresponding to a reservation resource used for data transmission by the user equipment; and a transmitter that transmits data using the reservation resource corresponding to the reservation resource identification information.

Abstract: A relay device of a mobile communication system supporting Device to Device (D2D) communication that includes a transmitter that transmits, on a second carrier, a broadcast message indicating that a relay process can be executed, the relay process being such that a message to be received on a first carrier is to be transmitted on the second carrier; and a relay unit that transmits, on the second carrier, the message received on the first carrier.