Abstract: A communication control method according to a present embodiment comprises: a step of transmitting, by a first base station, to a third base station that is a neighboring base station of the first base station, a first resource message relating to a first D2D resource used for the D2D proximity service in the first base station. The first resource message includes information on the first D2D resource and a second D2D resource used for the D2D proximity service in a second base station that is a neighboring base station of the first base station.

Abstract: A base station (200) according to an embodiment performs radio communication with a radio terminal (100). The base station transmits a reference signal to the radio terminal with a specific polarized wave, receives, from the radio terminal, polarized wave adjustment information generated by using the reference signal, adjusts a polarized wave based on the specific polarized wave by using the polarized wave adjustment information, and transmits an information signal to the radio terminal with the adjusted polarized wave.

Abstract: A user terminal, user terminal chipset, and method including receiving, from a cellular base station included in a cellular radio access network (RAN), parameters for an offload from the cellular RAN to a wireless local area network (LAN), and performs an access network selection between the cellular RAN and the wireless LAN based on the parameters. Parameters include a first threshold to be compared with a cellular signal strength of the cellular RAN, a second threshold to be compared with a wireless LAN signal strength of the wireless LAN, and a third threshold to be compared with a load of the wireless LAN. Performing the access network selection includes selecting the wireless LAN to perform the offload, in response to the cellular signal strength being lower than the first threshold, the wireless LAN signal strength being higher than the second threshold, and the load being lower than the third threshold.

Abstract: A base station according to one embodiment may comprise a receiver configured to receive first information from a radio terminal, the first information being transmitted based on a measurement result of a reception signal from a neighbouring cell; and a transmitter configured to transmit second information for reducing a transmission power of the radio terminal to the radio terminal when the measurement result of the reception signal from the radio terminal exceeds a threshold value.

Abstract: A radio terminal according to one embodiment comprises a controller configured to receive first control information for receiving, by the radio terminal, a special downlink control channel. The special downlink control channel carries control information to the radio terminal from a first cell with no connection for transmitting and receiving user data being established. The controller directly receives second control information for reducing an uplink interference in the first cell, on the special downlink control channel, from the first cell.

Abstract: A relay node according to one embodiment comprises a controller configured to establish a connection with a radio terminal and to establish a connection with a base station; a receiver configured to receive information of the radio terminal from the base station; and a transmitter configured to transmit the information to the radio terminal. The receiver receives delivery acknowledgement information from the radio terminal before the information is transmitted. The delivery acknowledgement information indicates that the radio terminal has received the information. The transmitter stops transmitting the information to the radio terminal in response to reception of the delivery acknowledgement information.

Abstract: A base station according to one embodiment comprises a controller configured to perform a downlink transmission process using a subframe. The subframe comprises a main PDCCH (Physical Downlink Control Channel) region located at a head portion of the subframe, and a data region other than the main PDCCH region. The data region comprises a short TTI region to which a short TTI (Transmission Time Interval) having a shorter time length than the subframe is applied. The short TTI region comprises a sub-PDCCH region. The controller is configured to arrange information indicating the sub-PDCCH region in the main PDCCH region.

Abstract: A communication control method comprises transmitting, by a user terminal to a base station, a message including information, where the information indicates a frequency used for receiving a discovery signal from another user terminal in a discovery procedure for discovering a proximal terminal. The communication control method further comprises notifying, by the user terminal, the base station of a resource used in the discovery procedure and included in system information of a cell different from a serving cell of the user terminal.

Abstract: A radio terminal according to an embodiment is used in a mobile telecommunication system which provides a plurality of communication services. The radio terminal includes a controller which uses any of a plurality of resource pools provided for each communication service on the basis of resource map information. The plurality of resource pools is provided in one radio frame and in one system bandwidth. The resource map information indicates the layout pattern of the plurality of resource pools.

Abstract: A transmission device (100) transmits transmission information to a reception device (200) via a radio channel. The transmission device (100) includes: a grouping unit (110) configured to divide the transmission information into a plurality of information groups; an error detection code adding unit (120) configured to add an error detection code to each of the plurality of information groups; and a transmission processing unit (140) configured to perform a process of transmitting the plurality of information groups to the reception device (200). The transmission processing unit (140) performs, for each information group included in the plurality of information groups, a transmission process by using a method having different error tolerance on the radio channel.

Abstract: A mobile communication system is a mobile communication system that performs communication between a base station and a user terminal. When a directivity is formed to transmit a radio signal, the base station transmits a first radio signal including identification information to identify the formed directivity and a reference signal. The user terminal receives the first radio signal and transmits a second radio signal including quality information when receiving the reference signal and the identification information. The base station receives the second radio signal and determines the directivity to be formed based on the identification information and the quality information.

Abstract: A communication method comprises a communication apparatus managing a serving cell of a user terminal and broadcasting to the user terminal system information for Device to Device (D2D) proximity service using a frequency of the serving cell. The user terminal performing a discovery procedure to discover another user terminal on a basis of the system information, which includes first information that indicates an available frequency for the discovery procedure different from the frequency of the serving cell and related to a center frequency of a frequency band of the available frequency, second information that indicates at least one parameter for calculating transmission power for the discovery procedure, third information that indicates a Public Land Mobile Network (PLMN) identifier for the available frequency, and fourth information that indicates number of times of re-transmissions of a discovery signal to be re-transmitted by one user terminal in the discovery procedure.

Abstract: A user terminal comprises a controller configured to measure a state on a downlink channel; transmitter configured to transmit, to a base station, channel state information on the state; and a receiver configured to receive, from the base station, control information on an uplink channel state measured by the base station. The controller is configured to adaptively modify, on the basis of the control information, the number of bits of the channel state information.

Abstract: A transmission device (100) transmits transmission information to a reception device (200) via a radio channel. The transmission device (100) includes: a grouping unit (110) configured to divide the transmission information into a plurality of information groups; an error detection code adding unit (120) configured to add an error detection code to each of the plurality of information groups; and a transmission processing unit (140) configured to perform a process of transmitting the plurality of information groups to the reception device (200). The transmission processing unit (140) performs, for each information group included in the plurality of information groups, a transmission process by using a method having different error tolerance on the radio channel.

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 mobile communication system, which supports D2D communication that is direct device to device communication, comprises: a user terminal that transmits a discovery signal that is used for discovering a communication partner terminal in the D2D communication, wherein the user terminal transmits the discovery signal when the user terminal accepts start of communication and the user terminal has difficulty to establish a connection with a base station.

Abstract: A communication control method comprises: transmitting, by a communication apparatus, a Device to Device (D2D) resource notification to a user terminal. The D2D resource notification includes information indicating a predetermined D2D radio resource available in a D2D proximity service and information indicating a condition not allowing for use of the predetermined D2D radio resource.

Abstract: A communication control method pertaining to an embodiment of the present invention is for controlling dual connectivity communication which uses a master base station that establishes RRC connection with a user terminal and a secondary base station that provides a supplementary wireless resource to the user terminal. The communication control method comprises: a step in which the master base station receives, from the user terminal, a measurement report which includes measurement results found for each cell in the user terminal; and a step in which the secondary base station receives, from the master base station, a supplementary request for requesting the allocation of resources to the user terminal. In the step for receiving a supplementary request, the master base station includes, in the supplementary request, measurement results for a cell of the secondary base station which is included in the measurement results, and transmits the same.

Abstract: A mobile communication system is a mobile communication system that performs communication between a base station and a user terminal. When a directivity is formed to transmit a radio signal, the base station transmits a first radio signal including identification information to identify the formed directivity and a reference signal. The user terminal receives the first radio signal and transmits a second radio signal including quality information when receiving the reference signal and the identification information. The base station receives the second radio signal and determines the directivity to be formed based on the identification information and the quality information.

Abstract: A communication apparatus according to one embodiment comprises an antenna array having antenna elements arranged in rows and columns, and a transmitter configured to simultaneously use specific antenna elements that are some antenna elements out of all antenna elements of the antenna array to transmit a reference signal. At least one of the specific antenna elements is arranged in each row and each column of the antenna array.