Abstract: A terminal apparatus that performs communication using a communication path set between the terminal apparatus and a core network via a base station apparatus connected to the core network or via the base station apparatus and a relay apparatus that relays communication with the base station apparatus acquires information regarding candidates of a communication path to which switching should be performed from a first communication used, from the base station apparatus that functions as a serving base station in the first communication path, determines whether or not to perform switching of the communication path from the first communication path, and performs switching from the first communication path to a second communication path included in the candidates without being instructed by the serving base station, in response to the determination to perform the switching after receiving the information regarding the candidates.

Abstract: A terminal device that can be connected to one or more base station devices that each form one or more beams is described. The terminal device monitors, when the terminal device is not connected to any of the one or more base station devices, a connection target beam to be used when the terminal device establishes a connection with any of the one or more base station devices; and reports, at least based on a fact that the connection target beam has transitioned, information regarding the connection target beam to a base station device that forms the connection target beam. A base station device among the one or more base station devices to execute paging of the terminal device and a beam to be used in the paging are controlled based on the information regarding the connection target beam.

Abstract: A base station device transmits a control signal for causing a transition from an RRC_CONNECTED state to an RRC_INACTIVE state and including connection parameter information to a terminal device. The terminal device performs uplink transmission to the base station device using the connection parameter information included in the control signal in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned. The base station device performs uplink reception from the terminal device that is in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned using the connection parameter information included in the control signal.

Abstract: A base station device transmits a control signal for causing a transition from an RRC_CONNECTED state to an RRC_INACTIVE state and including connection parameter information to a terminal device. The terminal device performs uplink transmission to the base station device using the connection parameter information included in the control signal in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned. The base station device performs uplink reception from the terminal device that is in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned using the connection parameter information included in the control signal.

Abstract: A base station device transmits a control signal for causing a transition from an RRC_CONNECTED state to an RRC_INACTIVE state and including connection parameter information to a terminal device. The terminal device performs uplink transmission to the base station device using the connection parameter information included in the control signal in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned. The base station device performs uplink reception from the terminal device that is in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned using the connection parameter information included in the control signal.

Abstract: A terminal apparatus that performs communication using a communication path set between the terminal apparatus and a core network via a base station apparatus connected to the core network or via the base station apparatus and a relay apparatus that relays communication with the base station apparatus acquires information regarding candidates of a communication path to which switching should be performed from a first communication used, from the base station apparatus that functions as a serving base station in the first communication path, determines whether or not to perform switching of the communication path from the first communication path, and performs switching from the first communication path to a second communication path included in the candidates without being instructed by the serving base station, in response to the determination to perform the switching after receiving the information regarding the candidates.

Abstract: A terminal apparatus that performs communication using a communication path set between the terminal apparatus and a core network via a base station apparatus connected to the core network or via the base station apparatus and a relay apparatus that relays communication with the base station apparatus acquires information regarding candidates of a communication path to which switching should be performed from a first communication used, from the base station apparatus that functions as a serving base station in the first communication path, determines whether or not to perform switching of the communication path from the first communication path, and performs switching from the first communication path to a second communication path included in the candidates without being instructed by the serving base station, in response to the determination to perform the switching after receiving the information regarding the candidates.

Abstract: A terminal apparatus transmits message 1 of a 4-step random access procedure using information of a first beam among a plurality of beams formed by a base station apparatus in order to connect to the base station apparatus, receives, from the base station apparatus, message 2 of the random access procedure as a response to the message 1, and transmits, in response to the message 2, message 3 of the random access procedure including information of a second beam as a beam serving a candidate for switching from the first beam based on radio qualities measured for the plurality of beams after transmitting the message 1.

Abstract: A terminal apparatus that establishes, on the basis of a two-step random access procedure, an initial connection with a base station apparatus by transmitting a first message to the base station apparatus and receiving a second message, which is a reply to the first message, from the base station apparatus, is provided. The first message includes a preamble to be transmitted using one sequence selected from a plurality of sequence candidates and predetermined information for initial access, each one of the plurality of sequence candidates is associated with a radio resource to be used for transmitting the predetermined information, wherein a first radio resource associated with a first candidate of the plurality of sequence candidates is different from a second radio resource associated with a second candidate of the plurality of sequence candidates.

Abstract: A terminal apparatus, which executes a two-step random access procedure or a four-step random access procedure to establish a connection with a base station apparatus, executes control such that, in a case where a first message of the two-step random access procedure including a preamble and predetermined information for connection establishment is transmitted and a number of unsuccessful attempts to receive the first message by the base station apparatus exceeds a predetermined number, the terminal apparatus transmits a second message to be transmitted from the terminal apparatus to the base station apparatus in the four-step random access procedure.

Abstract: A terminal apparatus, which is able to establish a connection with a base station apparatus via a two-step random access procedure by transmitting a first signal including a random access preamble and predetermined information to the base station apparatus and receiving a second signal as a reply to the first signal from the base station apparatus, acquires a random access-radio network temporary identifier (RA-RNTI) on the basis of a radio resource having been used to transmit the predetermined information with the first signal, and executes reception processing of the second signal using the RA-RNTI.

Abstract: A terminal device that can be connected to one or more base station devices that each form one or more beams is described. The terminal device monitors, when the terminal device is not connected to any of the one or more base station devices, a connection target beam to be used when the terminal device establishes a connection with any of the one or more base station devices; and reports, at least based on a fact that the connection target beam has transitioned, information regarding the connection target beam to a base station device that forms the connection target beam. A base station device among the one or more base station devices to execute paging of the terminal device and a beam to be used in the paging are controlled based on the information regarding the connection target beam.

Abstract: A communication apparatus, which is capable of performing, in a predetermined frequency band to be used by a first radio communication system configured to periodically transmit a reference signal with a predetermined frequency spacing, communication using a second radio communication system that is different from the first radio communication system, performs communication of the second radio communication system while the base station apparatus of the first radio communication system operates in a mode in which periodic transmission of the reference signal is stopped for a predetermined period, based on information relating to a timing at which a base station apparatus of the first radio communication system is to operate in the mode.

Abstract: A terminal device that can be connected to one or more base station devices that each form one or more beams is described. The terminal device monitors, when the terminal device is not connected to any of the one or more base station devices, a connection target beam to be used when the terminal device establishes a connection with any of the one or more base station devices; and reports, at least based on a fact that the connection target beam has transitioned, information regarding the connection target beam to a base station device that forms the connection target beam. A base station device among the one or more base station devices to execute paging of the terminal device and a beam to be used in the paging are controlled based on the information regarding the connection target beam.

Abstract: A terminal comprises a function capable of operating in a plurality of states that include a first state in which a connection with a base station has been established, and a second state in which a connection with a base station has not been established, but the base station holds information regarding the terminal device. After starting operation in the second state from a state in which the terminal operates with a first base station in the first state, if predetermined information that enables communication with the first base station in the second state and that has been acquired from the first base station in the first state is held, the terminal determines whether a signal transmission target has changed from the first base station to a second base station device, and performs communication according to a result of the determination.

Abstract: A base station device transmits a control signal for causing a transition from an RRC_CONNECTED state to an RRC_INACTIVE state and including connection parameter information to a terminal device. The terminal device performs uplink transmission to the base station device using the connection parameter information included in the control signal in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned. The base station device performs uplink reception from the terminal device that is in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned using the connection parameter information included in the control signal.

Abstract: A terminal operable in a first state where connection with a base station is established and a second state where connection with the base station is not established but the base station holds information regarding the terminal is provided. The terminal receives, from the base station, information regarding whether to establish time synchronization when a signal is to be transmitted to the base station in the second state, determines, based on the information, as to whether to establish time synchronization when transmitting a signal to the base station in the second state, and transmits a signal to the base station in the second state, with executing processing for establishing time synchronization with the base station if time synchronization is to be established, and without executing the processing if time synchronization is not to be established.

Abstract: A communication device, which is capable of performing communication via a second wireless communication system that is different from a first wireless communication system, in a frequency band that is used by the first wireless communication system, the first wireless communication system periodically transmitting a reference signal, transmits, to a base station device of the first wireless communication system, information for operating the base station device in a mode in which the periodical transmission of the reference signal is interrupted for a predetermined period, and performs communication involving a predetermined signal of the second wireless communication system while the base station device of the first wireless communication system is operating in the mode.

Abstract: A terminal apparatus that performs communication using a communication path set between the terminal apparatus and a core network via a base station apparatus connected to the core network or via the base station apparatus and a relay apparatus that relays communication with the base station apparatus acquires information regarding candidates of a communication path to which switching should be performed from a first communication used, from the base station apparatus that functions as a serving base station in the first communication path, determines whether or not to perform switching of the communication path from the first communication path, and performs switching from the first communication path to a second communication path included in the candidates without being instructed by the serving base station, in response to the determination to perform the switching after receiving the information regarding the candidates.

Abstract: A base station device, which provides a terminal device with communication via a relay device or direct communication, selects a communication path between the terminal device and a core network when the terminal device executes handover, and provides a notification regarding the handover executed by the terminal device, to each of one or more devices that constitute the selected communication path. A connection between the terminal device and the core network is established based on the notification, using the selected communication path.