Abstract: In a case where a relay terminal (110) exists inside an area (102) where radio waves from a base station (101) reach while a remote terminal (130) exists outside the area (102) where the radio waves from the base station (101) reach, when receiving emergency warning information which is information for notification of an emergency situation from the base station (101), the relay terminal (110) transmits the emergency warning information to the remote terminal (130) by using a connection that has been established between the relay terminal and the remote terminal (130) for one-to-one communication using a Physical Sidelink Shared CHannel (PSSCH).

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 base station (10) according to the present invention includes a reception processing unit (104) that receives a signal for use in positioning transmitted from a terminal device, and a positioning processing unit (106) that computes the location of the terminal device using the signal for use in positioning.

Abstract: A communication system includes: a first base station that operates as a donor for integrated access and backhaul, the first base station including a central unit and a distributed unit; and one or more second base stations that operate as nodes of the integrated access and backhaul, and in a case where multicast transmission of data is performed from the first base station to a communication terminal, the central unit performs a configuration for the multicast transmission on the distributed unit and the one or more second base stations.

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: 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 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 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 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.

Abstract: A communication system includes: a base station; and a communication terminal connected to the base station, and in a case where the base station causes the communication terminal to transmit a data signal, the base station notifies the communication terminal of information about a demodulation reference signal to be transmitted together with a data signal, and the communication terminal transmits a data signal and a demodulation reference signal in accordance with the information provided from the base station.

Abstract: A communication system includes a base station and a communication terminal connected to the base station. The base station transmits a result of reception of an uplink positioning signal transmitted by the communication terminal and location information of the base station to a positioning device that is a device having a positioning function of deriving a location of the communication terminal, and the communication terminal transmits a result of reception of a downlink positioning signal transmitted by the base station to the positioning device.

Abstract: A communication system includes a user apparatus; and base stations respectively configured to wirelessly communicate with the user apparatus. The base stations include a master base station and a secondary base station that configure dual connectivity for the user apparatus. The secondary base station is configured with a grant configuration related to transmission without grant in uplink to the secondary base station.

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.