Abstract: A communication terminal apparatus in a communication system includes a plurality of communication terminal apparatuses including the communication terminal apparatus. The communication terminal apparatus is configured to perform PC5 communication, which is communication via a PC5 interface, with another communication terminal apparatus of the plurality of communication terminal apparatuses. The communication terminal apparatus is configured to configure a validity time limit for a resource of the PC5 communication.

Abstract: A communication system that can reduce latency while preventing reduction in a transmission rate. An eNB communicates with a UE #1 using a self-contained subframe including a first downlink signal (DL #1) and a first uplink signal (UL #1), and with a UE #2 using a self-contained subframe including a second downlink signal (DL #2) and a second uplink signal (UL #2). The self-contained subframe for the UE #1 includes a first gap duration (Gap #1) during which neither the DL #1 nor the UL #1 is transmitted, between transmission durations of the DL #1 and the UL #1. The self-contained subframe for the UE #2 includes a second gap duration (Gap #2) during which neither the DL #2 nor the UL #2 is transmitted, between transmission durations of the DL #2 and the UL #2. The Gaps #1 and #2 are set to each UE.

Abstract: A user apparatus in a communication system includes: a plurality of user apparatuses each of which is configured to transmit a sounding reference signal (SRS); and a base station configured to wirelessly communicate with the plurality of the user apparatuses. The user apparatus receives, from the base station, configuration information related to a wireless resource of the sounding reference signal allocated to another user apparatus.

Abstract: A radio communication technology for enabling high reliability, a high transmission rate, and low power consumption is provided. A communication system includes a communication terminal and a base station. The base station includes a plurality of transmitter-receivers configured to perform radio communication with the communication terminal. The base station is configured to perform radio communication with the communication terminal by using a part or all of the plurality of transmitter-receivers. The communication terminal receives a downlink synchronization signal from at least one first transmitter-receiver to be newly connected, and establishes downlink synchronization with the at least one first transmitter-receiver by using the downlink synchronization signal. The communication terminal establishes uplink synchronization with the at least one first transmitter-receiver through random access processing.

Abstract: Provided is a technology that can increase the robustness of a communication system. A communication system includes: a communication terminal; a first network configured to perform radio communication with the communication terminal; and at least one second network configured to perform communication with the first network. When the first network determines to release connection between the first network and the communication terminal (ST1401) with the communication terminal being connected to the first network and to the at least one second network through the first network, the communication terminal or the first network instructs the at least one second network to release the connection with the communication terminal (ST1405).

Abstract: A user apparatus in a communication system includes: a plurality of user apparatuses each of which is configured to transmit a sounding reference signal (SRS); and a base station configured to wirelessly communicate with the plurality of the user apparatuses. The user apparatus receives, from the base station, configuration information related to a wireless resource of the sounding reference signal allocated to another user apparatus.

Abstract: Provided is a communication system that can be normally and efficiently operated in the case where existing carriers and new carrier types coexist. A base station device and a communication terminal device are configured to perform communication in cells of legacy carriers LC1 to LC3 being existing carriers. When the base station device starts operating new carrier types NCT1 and NCT2, the NCT1 and NCT2 are associated with legacy carriers belonging to the same frequency band. For example, the NCT2 is associated with the LC2 or the LC3 and is not associated with the LC1. The legacy carriers LC1 to LC3 associated with the NCT1 and the NCT2 notify the communication terminal device of the information on the NCT1 and NCT2. This allows the communication terminal device to communicate with the NCT1 and the NCT2.

Abstract: A communication system includes a user apparatus; and a base station including a distributed unit (DU) configured to wirelessly communicate with the user apparatus and a central unit (CU) connected to the distributed unit. The base station including the CU and the DU supports packet duplication, and the DU notifies the user apparatus of starting the packet duplication.

Abstract: A communication system includes a communication terminal, base stations performing radio communication with the communication terminal, and a host device of the base stations. A serving base station of the communication terminal or the host device selects, from among the base stations, a positioning base station transmitting a positioning signal for measuring a position of the communication terminal. The positioning base station transmits the positioning signal, and the communication terminal receives the positioning signal.

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: A communication system is configured with a central unit and a distributed unit, includes a first base station that operates as a donor for integrated access and backhaul and one or more second base stations that operate as nodes for the integrated access and backhaul, and the central unit performs address configuration for multicasting data from a central unit toward a communication terminal in a backhaul adaptation layer in which data transmitted and received by the communication terminal is routed, on the distributed unit and the second base stations.

Abstract: A communication system includes: a communication terminal that encodes transmission data by using an encoding model that encodes and outputs data that has been input; and a base station that decodes data encoded with the encoding model by using a decoding model that, when encoded data is input, decodes and outputs the data, the encoding model performs encoding on channel state-related data that is data on a channel state between the communication terminal and the base station, and the base station executes machine learning using learning data including the channel state-related data in an un-encoded state to generate the encoding model and the decoding model, and notifies the communication terminal of a learning result of the encoding model.

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: 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 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: In a mobile communication system according to the present invention, with the separate use of a plurality of component carriers or with the use of a carrier set including the plurality of component carriers aggregated, a base station performs radio communication with a user equipment corresponding to the component carrier or a user equipment corresponding to the aggregated carriers. In particular, in a case where the base station performs radio communication with the user equipment corresponding to the aggregated carriers with the use of the aggregated carriers, each of a plurality of transport blocks created by dividing a transport channel is transmitted per each of the plurality of component carriers constituting the aggregated carriers, and control information related to radio communication between the base station and the user equipment corresponding to the aggregated carriers is transmitted such that physical information of the corresponding component carrier is identifiable.

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.