Abstract: A closed subscriber group (CSG) cell is a cell that allows use of subscribers. In order to receive the service by the CSG cell, a CSG-ID is required to be notified to a user equipment, which cannot be obtained in a situation outside the reach of radio waves from a non-CSG cell. In a mobile communication system including base stations respectively provided to a CSG cell and a non-CSG cell in which access is made to the CSG cell with the use of a CSG-ID issued in a case where use of the CSG cell is allowed, the base station provided in the CSG cell refers to the notified identification information of a user equipment and then transmits a tracking area update request from the user equipment to a core network, and the core network determines whether the user equipment is allowed to use the CSG cell and, in the case where the use is allowed, transmits a signal for allowing assignment of radio resources to the user equipment and the CSG-ID. The user equipment accesses the CSG cell with the use of the CSG-ID.

Abstract: When being connected to a macro cell (S-MeNB) and a small cell (SeNB), a user equipment device performs a pre-handover process of disconnecting the connection with the SeNB before a handover process of switching a macro cell connected with the UE from the macro cell (S-MeNB) that is a moving source to a macro cell (T-MeNB) that is a moving destination along with moving of the UE, and after the handover process, performs a post-handover process of reestablishing the connection with the SeNB.

Abstract: In a communication system, a plurality of base stations includes an MeNB being a first base station, and a plurality of SeNBs to be connected to the MeNB. At least one of control plane data about control of communication and user plane data about a user is transmitted to and received from a user equipment (UE) via the first base station being the MeNB. The control plane data and the user plane data are contained in information provided by a core network about communication with the UE. The communication system can simplify processing of at least one of control plane data and user plane data when a communication terminal device communicates with a plurality of base station devices.

Abstract: A communication system includes a user equipment and a base station, in which a protocol stack between the user equipment and the base station includes PDCP, RLC, MAC and PHY. The base station includes a first node and one or more second nodes, the first node terminates the PDCP, each of the second nodes terminates the RLC, the MAC and the PHY. The base station is configured to perform radio communication with the user equipment that terminates the PDCP, the RLC, the MAC and the PHY.

Abstract: A communication system includes: a base station conforming to New Radio Access Technology; and a communication terminal capable of performing multicast communication with the base station. While executing the multicast communication, the communication terminal transmits reception status information to the base station in communication with the communication terminal, the reception status information being information related to a data reception status, and the base station performs control of retransmission of data to the communication terminal on the basis of the reception status information.

Abstract: A communication system includes a terminal apparatus; and a plurality of base stations respectively configured to wirelessly communicate with the terminal apparatus, the base stations including an MgNB and an SgNB that configures dual connectivity with the terminal apparatus. The terminal apparatus performs small data transmission for the SgNB in an RRC_INACTIVE state.

Abstract: The communication system includes: a first base station to which a first communication terminal is connected, the first communication terminal supporting terminal-to-terminal communication in which communication terminals directly communicate with each other; and a second base station to which a second communication terminal is connected, the second communication terminal supporting the terminal-to-terminal communication, and in a case where the second base station receives a handover request for the first communication terminal to connect to the second base station via the second communication terminal, the second base station transmits, to the first communication terminal and the second communication terminal, communication configuration information indicating the content of a configuration for the first communication terminal and the second communication terminal to perform terminal-to-terminal communication therebetween.

Abstract: Provided is a communication system capable of suppressing increase in the power consumption of a communication terminal device, degradation in the communication quality, and reduction in the use efficiency of radio resources. A base station device (gNB) notifies a communication terminal device (UE) of information on the next reception timing. The UE receives, for example, a downlink control signal in a subframe. The UE obtains, from the downlink control signal, information on a piece of user data in the subframe, and the information on the next reception timing. The UE transmits and receives the piece of user data to and from the gNB. The information on the next reception timing indicates a subframe as the next reception timing of the UE. The UE receives a downlink control signal in the subframe.

Abstract: A highly reliable communication system is provided, for example. A communication system includes a communication terminal device, and a plurality of base stations configured to perform radio communication with the communication terminal device. The plurality of base stations include a master base station and a secondary base station configuring dual connectivity with respect to the communication terminal device. When failure occurs in a secondary cell group (SCG) used for communication between the communication terminal device and the secondary base station, the master base station acquires latest SCG configuration.

Abstract: Provided is a high-speed communication system with the high reliability and the low latency under New Radio (NR). A base station device includes a plurality of distributed units (DUs, 802) that transmit and receive radio signals, and a central unit (CU, 801) that controls the plurality of DUs (802). The CU (801) duplicates a downlink packet addressed to a communication terminal device (804), and forwards the duplicated downlink packet to each of at least two DUs (802) among the plurality of DUs (802). Each of the at least two of the DUs (802) transmits, to the communication terminal device (804) by the radio signal, the downlink packet obtained from the CU (801). Upon redundant receipt of the downlink packets, the communication terminal device (804) removes a redundant downlink packet in accordance with a predefined downlink packet removal criterion.

Abstract: A closed subscriber group (CSG) cell allows use of subscribers. To receive the service by the CSG cell, a CSG-ID is notified to a user equipment, but cannot be obtained outside the reach of radio waves from a non-CSG cell. Base stations respectively provided to a CSG cell and a non-CSG cell, and access is made to the CSG cell with the use of a CSG-ID issued when use of the CSG cell is allowed, the base station refers to the notified identification information of a user equipment and then transmits a tracking area update request from the user equipment to a core network. The core network determines whether the user equipment is allowed to use the CSG cell and, if allowed, transmits a signal for assignment of radio resources to the user equipment and the CSG-ID. The user equipment accesses the CSG cell with the CSG-ID.

Abstract: Appropriate network data for an indoor map can be efficiently generated using input data including a structure of an indoor space. In a network data generation device (10) that generates, from the input data including at least the structure of the indoor space and information indicating a property based on the structure of the indoor space, network data, the network data including a link representing a movable space on a map and a node that is a starting point or an ending point of the link, a link/node generation unit (142) generates a set of links and a set of nodes based on the input data.

Abstract: A communication system includes a communication terminal device, a base station device performing radio communication with the communication terminal device, and a base station controller controlling the base station device. The communication terminal device is a machine type communication (MTC) device, The base station controller includes a mobility management entity (MME). Data is transmitted to the MME from the communication terminal device via the base station device.

Abstract: Provided is a communication system with low latency and high reliability, etc. Even after transitioning from RRC_CONNECTED to RRC_INACTIVE, a communication terminal device maintains secondary base station configuration information on configuring a secondary base station. Even when at least one of a master base station and a secondary base station is changed during the RRC_INACTIVE, the communication terminal device maintains the secondary base station configuration information. The communication terminal device again transitions to the RRC_CONNECTED using the maintained secondary base station configuration information.

Abstract: Provided is a high-speed communication system with the high reliability and the low latency under New Radio (NR). A base station device includes a plurality of distributed units (DUs, 802) that transmit and receive radio signals, and a central unit (CU, 801) that controls the plurality of DUs (802). The CU (801) duplicates a downlink packet addressed to a communication terminal device (804), and forwards the duplicated downlink packet to each of at least two DUs (802) among the plurality of DUs (802). Each of the at least two of the DUs (802) transmits, to the communication terminal device (804) by the radio signal, the downlink packet obtained from the CU (801). Upon redundant receipt of the downlink packets, the communication terminal device (804) removes a redundant downlink packet in accordance with a predefined downlink packet removal criterion.

Abstract: Provided is a technology that can maintain the reliability and the transmission rate in the communication. A communication system includes a communication terminal, and a first base station and a second base station that are configured to perform radio communication with the communication terminal. The first base station notifies the second base station of information on a numerology to be used for communication between the first base station and the communication terminal when the first base station and the second base station provide the communication terminal with dual connectivity using a same frequency band (Steps ST1501 and ST1502).

Abstract: A communication system includes base stations and a communication terminal. Once the communication terminal connected to a base station enters a state in which communication with another communication terminal is available, the other communication terminal being served by another base station, the communication terminal notifies the base station of connection state information indicating that the communication terminal has entered the state. The base station determines, based on the information, whether to change a connection destination of the communication terminal, to the other base station via the other communication terminal, and requests the communication terminal to release connection with the base station in response to determining to change the connection destination In response to being requested by the base station to release the connection, the communication terminal releases the connection, and connects to the other base station via the other communication terminal.

Abstract: A communication system capable of a stable communication operation between a base station device and a communication terminal device. A UE is configured to communicate with an MeNB directly or through a SeNB. The UE is set to transmit, to the MeNB and the SeNB, transmission data addressed to the MeNB when an amount of the transmission data exceeds a predetermined threshold. The UE is set to transmit the transmission data not to the SeNB but to the MeNB when the amount is smaller than or equal to the threshold. The threshold is changed so that the transmission data is transmitted to the MeNB and the SeNB, when the SeNB is set to communicate with the UE with radio resources periodically allocated and the amount of the transmission data is smaller than or equal to the threshold.

Abstract: A communication terminal is capable of sidelink communication for directly communicating with another communication terminal. When being in coverage of a base station, the communication terminal is given an allocation for executing, on behalf of a higher-level device in a core network, all or part of a location management function (LMF) including a position derivation function that is a function of deriving a position of a communication terminal. The communication terminal executes, based on a result of the sidelink communication with another communication terminal, a positioning function of deriving a position of the other communication terminal, instead of the higher-level device.

Abstract: Radio resource management is simplified when a cell is spatially separated by a plurality of radio beams. A cell configured by a base station device is spatially separated by a plurality of radio beams being served by the base station device. The base station device shares, between two or more of the plurality of radio beams, a radio resource control (RRC) parameter to be applied to a communication terminal device.