Abstract: A user equipment, method used in a user equipment, and an apparatus for a user equipment include receiving from a first cell operated in a licensed band, configuration information configuring a second cell operated in an unlicensed band, performing a listen-before-talk (LBT) procedure on the second cell, counting a number of failures of the LBT procedure on the second cell, and transmitting information based on the number of failures of the LBT procedure on the second cell, to the first cell operated in the licensed band, the information indicating the failure of the LBT procedure on the second cell.

Abstract: A user equipment, method used in user equipment, and apparatus for controlling a user equipment operate to receiving a connected mode DRX parameter configured by a base station, and transmit to the base station a message including information indicating a connected mode DRX parameter preferred by the user equipment. The connected mode DRX parameter preferred by the user equipment includes at least one of DRX-InactivityTimer, DRX-ShortCycle, and DRX-ShortCycleTimer.

Abstract: A user equipment, method used in a user equipment, and an apparatus for a user equipment include receiving from a first cell operated in a licensed band, configuration information configuring a second cell operated in an unlicensed band, performing a listen-before-talk (LBT) procedure on the second cell, counting a number of failures of the LBT procedure on the second cell, and transmitting information based on the number of failures of the LBT procedure on the second cell, to the first cell operated in the licensed band, the information indicating the failure of the LBT procedure on the second cell.

Abstract: A user terminal, method used in a user terminal, and an apparatus for a user terminal include receiving from a base station measurement configuration information configuring measurement of a frequency channel in an unlicensed band, measuring signal strength of radio signals transmitted in the frequency channel, determining occupancy situation of the frequency channel based on the measured signal strength and a threshold, and transmitting to the base station a measurement report including information indicating the occupancy situation of the frequency channel.

Abstract: A user equipment, method and apparatus receive a PDSCH from a base station and determine a modulation order used in the PDSCH based on whether the PDSCH is transmitted in a second slot out of a first slot and the second slot which configure a subframe.

Abstract: A base station (200) according to one embodiment uses a specific frequency band shared by a plurality of operators and/or a plurality of communication systems. The base transmit, to a radio terminal (100-1), interference-related information relating to interference detected by the base station in the specific frequency band.

Abstract: A user equipment, apparatus and method comprise starting reception from a base station from a second slot out of a first slot and the second slot which configure a subframe, determining a first modulation order used for downlink control information transmitted in the second slot, and starting the reception from the second slot by using the first modulation order. The downlink control information is a PDCCH or an EPDCCH.

Abstract: A user equipment, method and apparatus receive a PDSCH from a base station and determine a modulation order used in the PDSCH based on whether the PDSCH is transmitted in a second slot out of a first slot and the second slot which configure a subframe.

Abstract: A base station according to an embodiment includes a controller configured to perform a process of transmitting, in a specific frequency band shared by a plurality of operators and/or a plurality of communication systems, a burst signal including data or a control signal and a discovery reference signal including a reference signal and/or a synchronization signal. If there is a transmission duration of the discovery signal within a transmission duration of the burst signal after starting the transmission of the burst signal, the controller performs a process of transmitting the discovery reference signal even within the transmission duration of the burst signal.

Abstract: A user equipment, method used in user equipment, and apparatus for controlling a user equipment operate to receiving a connected mode DRX parameter configured by a base station, and transmit to the base station a message including information indicating a connected mode DRX parameter preferred by the user equipment. The connected mode DRX parameter preferred by the user equipment includes at least one of DRX-InactivityTimer, DRX-ShortCycle, and DRX-ShortCycleTimer.

Abstract: A communication method according to an embodiment comprises: notifying, by a base station, a radio terminal of a discontinuous reception (DRX) cycle; notifying, by a Mobility Management Entity (MME), the radio terminal of an extended DRX cycle longer than the DRX cycle; determining, by the radio terminal, whether or not the base station supports an extend DRX; using, by the radio terminal, the extended DRX cycle to execute an extended DRX operation in an idle mode, in response to determining that the base station supports the extend DRX; and using, by the radio terminal, the DRX cycle to execute a DRX operation without using the extended DRX cycle, in response to determining that the base station does not support the extend DRX.

Abstract: A user terminal, method used in a user terminal, and an apparatus for a user terminal include receiving from a base station measurement configuration information configuring measurement of a frequency channel in an unlicensed band, measuring signal strength of radio signals transmitted in the frequency channel, determining occupancy situation of the frequency channel based on the measured signal strength and a threshold, and transmitting to the base station a measurement report including information indicating the occupancy situation of the frequency channel.

Abstract: A user terminal according to an embodiment transmits uplink data to a base station using an unlicensed band. The user terminal includes a controller configured to, if uplink data transmission is started from a middle of a subframe according to a monitoring result of the unlicensed band, perform processing of transmitting a specific signal being different from the uplink data, at a beginning of the uplink data.

Abstract: A base station (eNB 200-1) operated in a specific frequency band shared by a plurality of operators or a plurality of communication systems transmits, to another base station (eNB 200-2) operated in the specific frequency band, transmission request information requesting transmission of a predetermined signal for stopping transmission of an interference signal by an interference source (UE 100-2) causing interference to a radio terminal (UE 100-1) connected to the base station.

Abstract: A user terminal according to a first feature is used in a mobile communication system. The use terminal includes: a receiver configured to receive a measurement instruction to instruct measurement in an unlicensed band, from a base station; a controller configured to, in response to reception of the measurement instruction, search for a radio signal transmitted in a frequency channel included in the unlicensed band, and measure reception power of the radio signal detected by the search, even when a cell identifier of a measurement target cell is not designated in the measurement instruction; and a transmitter configured to transmit a measurement report including an identifier of a transmission source of the detected radio signal and a measurement result of the reception power, to the base station.

Abstract: A user terminal according to first to third embodiments is used in a mobile communication system defined to observe a use state of an unlicensed band channel within an observation period before transmitting an uplink signal within an uplink transmission period in the channel. The user terminal includes a controller configured to perform transmission restriction to restrict transmission of the uplink signal during a last fixed section or a first fixed section of the uplink transmission period when transmitting the uplink signal within the uplink transmission period in the channel.

Abstract: A user equipment, apparatus and method comprise starting reception from a base station from a second slot out of a first slot and the second slot which configure a subframe, determining a first modulation order used for downlink control information transmitted in the second slot, and starting the reception from the second slot by using the first modulation order. The downlink control information is a PDCCH or an EPDCCH.

Abstract: A user terminal according to a first aspect is used in a mobile communication system. The user terminal comprises: a receiver configured to receive, from a base station, candidate timing information indicating candidate timings of an uplink transmission on an unlicensed band channel that is a frequency channel of an unlicensed band; a controller configured to determine, by monitoring the unlicensed band channel, a transmission timing at which the uplink transmission to the base station is performed, from the candidate timings indicated by the candidate timing information; and a transmitter configured to transmit, at the transmission timing, uplink data via the unlicensed band channel to the base station.

Abstract: A base station according to an embodiment is a base station configured to perform transmission to a user terminal by use of an unlicensed band. The base station comprises: a controller configured to start the transmission from a boundary of a subframe, but also to start the data transmission from a second-half slot out of a first-half slot and the second-half slot which configure a subframe. The controller is configured to transmit downlink control information in the second-half slot to start the transmission from the second-half slot. The controller is configured to change a modulation scheme to be applied to the transmission, depending on a start timing of the transmission, while fixing a transport block size applied to the subframe. The downlink control information is a PDCCH or an EPDCCH.

Abstract: In the communication control method according to the present embodiment, a user terminal transmits a scheduling assignment indicating the location of a radio resource used in a reception of communication data by direct device-to-device communication. The user terminal transmits the communication data including initial transmission data and retransmission data by using the radio resource. The retransmission data is transmitted depending on the number of times of re-transmissions associated with a predetermined scheduling assignment by using a predetermined radio resource of which the location is indicated by the predetermined scheduling assignment.