Abstract: A mobile communication system comprises: a switching control unit that controls switching of communication to be performed by the second radio terminal between the first communication and the second communication, on the basis of received quality of a downlink signal received in the second radio terminal from the radio base station when the first radio terminal performs the first communication. The first radio terminal relays user data, which is transferred through the second communication, between the second radio terminal and the radio base station when the first radio terminal performs the first communication and the second radio terminal performs the second communication.

Abstract: A network apparatus according to an embodiment performs communication with a user terminal comprising a first communication unit configured to perform communication using a first radio access technology and a second communication unit configured to perform communication using a second radio access technology, by using the first access technology. The network apparatus comprises: a receiver configured to receive, from the user terminal, authentication related information on a country where the user terminal is legally authenticated for transmission by the second communication unit; and a controller configured to determine, based on the authentication related information, whether or not communication by the second communication unit can be configured to the user terminal.

Abstract: A radio communication apparatus according to one embodiment is mounted on a vehicle (V), configured to perform vehicle-to-vehicle communication with another vehicle by using a predetermined frequency band. The radio communication apparatus comprises a controller configured to control a transmission power and/or a transmission directivity in the vehicle-to-vehicle communication to restrain generation of interference in the predetermined frequency band, based on a congestion situation parameter regarding a congestion situation of a road (R) on which the vehicle travels.

Abstract: A base station according to a first feature uses a plurality of carriers for radio communications. The base station includes: a receiver that receives neighbor base station information on user terminals connected to a neighbor base station, wherein the neighbor base station information is transmitted from the neighbor base station; and a controller that changes a carrier configuration of at least one carrier among the plurality of carriers based on the neighbor base station information.

Abstract: A base station according to a first feature is used in a mobile communication system in which a plurality of functions related to radio communication are specified. The base station includes a receiver that receives processor information related to a load state or an attribute of an processor included in a radio terminal from the radio terminal, a controller that selects at least one function to be executed by the radio terminal on the basis of the processor information, and a transmitter that transmits information indicating the selected function to the radio terminal.

Abstract: A base station is used for a mobile communication system that supports a dual connectivity. The base station includes a controller configured to establish an RRC connection with a user terminal, and to perform a mobility control in the dual connectivity.

Abstract: UE 100 performs, in a mobile communication system in which a small cell is arranged within a coverage of a macro cell, a cell reselection on the basis of neighboring cell information broadcast from the macro cell. The UE 100 acquire, in a connected state in which the UE 100 is connected to the macro cell, from a server 400 that manages small cell information on the small cell, the small cell information via the macro cell. The neighboring cell information broadcast from the macro cell is information on a neighboring cell other than the small cell. The UE 100 performs, in an idle state, the cell reselection on the small cell on the basis of the small cell information acquired from the server 400.

Abstract: A radio base station according to an embodiment constitutes a mobile communication network. The radio base station comprises: a controller configured to measure a stay time for which a radio terminal has stayed on a wireless LAN. The stay time is a period from when a first process through which the radio terminal switches a waiting destination or a connection destination from the mobile communication network to the wireless LAN is performed to when a second process through which the radio terminal switches the waiting destination or the connection destination from the wireless LAN to the mobile communication network is performed.

Abstract: A base station is used for a mobile communication system that supports a dual connectivity. The base station includes a controller configured to establish an RRC connection with a user terminal, and to perform a mobility control in the dual connectivity.

Abstract: A radio terminal performs traffic steering between a mobile communication network and a wireless LAN. The radio terminal receives dedicated parameters notified individually from a cell provided in the mobile communication network. The dedicated parameters being determination parameters for determining whether or not to perform the traffic steering. The radio terminal discards the dedicated parameters when performing a connection process on the cell for transition to a Radio Resource Control (RRC) connected state after transition to an RRC idle state on the cell.

Abstract: A base station is used for a mobile communication system that supports a dual connectivity. The base station includes a controller configured to establish an RRC connection with a user terminal, and to perform a mobility control in the dual connectivity.

Abstract: A server apparatus, a communication apparatus, and a communication method are disclosed. Communication terminals forming a group are capable of performing push-to-talk group communication through the server apparatus. In reception of a call setting request from a first communication terminal of the group by the receiver, when the group includes a second communication terminal to which call setting fails, the transmitter transmits, to a communication terminal of the group, an instruction to execute a discovery processing of discovering a communication partner terminal capable of performing a direct communication with the communication terminal without passing through the server apparatus.

Abstract: A base station is used for a mobile communication system that supports a dual connectivity. The base station includes a controller configured to establish an RRC connection with a user terminal, and to perform a mobility control in the dual connectivity.

Abstract: A server apparatus, a communication apparatus, and a communication method are disclosed. Communication terminals forming a group are capable of performing push-to-talk group communication through the server apparatus. In reception of a call setting request from a first communication terminal of the group by the receiver, when the group includes a second communication terminal to which call setting fails, the transmitter transmits, to a communication terminal of the group, an instruction to execute a discovery processing of discovering a communication partner terminal capable of performing a direct communication with the communication terminal without passing through the server apparatus.

Abstract: A base station is used for a mobile communication system that supports a dual connectivity. The base station includes a controller configured to establish an RRC connection with a user terminal, and to perform a mobility control in the dual connectivity.

Abstract: UE 100 performs, in a mobile communication system in which a small cell is arranged within a coverage of a macro cell, a cell reselection on the basis of neighboring cell information broadcast from the macro cell. The UE 100 acquire, in a connected state in which the UE 100 is connected to the macro cell, from a server 400 that manages small cell information on the small cell, the small cell information via the macro cell. The neighboring cell information broadcast from the macro cell is information on a neighboring cell other than the small cell. The UE 100 performs, in an idle state, the cell reselection on the small cell on the basis of the small cell information acquired from the server 400.

Abstract: If an LTE base station (10-1) transmits an Earthquake and Tsunami Warning System (ETWS) signal from a core network (30) to mobile terminals (40), the LTE base station (10-1) determines that conditions are satisfied in which the traffic volume between the mobile terminals (40) is predicted to be at least a first predetermined value, adjusts the real amount of available wireless resources, and obtains an amount of available wireless resources after said adjustment. Additionally, the LTE base station (10-1) transmits a resource status response message, including the amount of available wireless resources after adjustment, to an adjacent LTE base station (10-2).

Abstract: A UE 100 comprises a controller configured to select either a normal mode in which D2D communication is controlled by a network or a public safety mode in which the D2D communication is controlled by the UE 100 instead of the network, as a mode to be applied to the D2D communication. The UE 100 selects either the normal mode or the public safety mode on the basis of a reception situation of a public safety allowance signal and a public safety prohibition signal transmitted depending on a situation of the network.

Abstract: A base station is used for a mobile communication system that supports a dual connectivity. The base station includes a controller configured to establish an RRC connection with a user terminal, and to perform a mobility control in the dual connectivity.

Abstract: A radio communication system comprises: a radio base station, a terminal device, and a plurality of relay devices that relay radio communication between the radio base station and the terminal device. The plurality of relay devices create communication quality information in radio communication between the relay devices and the radio base station. The terminal device preferentially connects to the relay device having the best communication quality based on each of the communication quality information.