Disclosed is a terminal and a base station for communicating each other by using a non-terrestrial network (NTN). A method of a terminal may include the steps of receiving, from a base station, configuration information for cell changing or beam failure recovery, determining, by using the configuration information, whether a trigger condition for cell changing or beam failure recovery is satisfied, and performing a cell changing or beam failure recovery operation when the trigger condition is satisfied; and an apparatus.

A moving state reporting method includes communicating, by a terminal, with a network device using a beam to carry a signal reporting, by the terminal, moving state information of the terminal to the network device, where the moving state information includes a speed flag, and the speed flag indicates that a speed of the terminal exceeds a speed threshold, and receiving, by the terminal, beam management information from the network device.

A moving state reporting method includes communicating, by a terminal, with a network device using a beam to carry a signal reporting, by the terminal, moving state information of the terminal to the network device, where the moving state information includes a speed flag, and the speed flag indicates that a speed of the terminal exceeds a speed threshold, and receiving, by the terminal, beam management information from the network device.

Aspects directed towards Quality of Service (QoS) flow remapping are disclosed. In an example, upon detecting a mapping reconfiguration of a first QoS flow from a first data radio bearer (DRB) to another DRB, a Service Data Adaptation Protocol (SDAP) control protocol data unit (PDU) is generated indicating that a final SDAP data PDU associated with the first QoS flow has been transmitted on the first DRB. The SDAP control PDU is then transmitted via the first DRB. In another example, upon detecting a mapping reconfiguration of a first QoS flow from a first DRB to another DRB, an end marker parameter is set in an SDAP header of a first SDAP data PDU received from an upper layer after the mapping reconfiguration indicating that the first SDAP data PDU is a final SDAP data PDU associated with the first QoS flow transmitted on the first DRB.

Aspects directed towards Quality of Service (QoS) flow remapping are disclosed. In an example, upon detecting a mapping reconfiguration of a first QoS flow from a first data radio bearer (DRB) to another DRB, a Service Data Adaptation Protocol (SDAP) control protocol data unit (PDU) is generated indicating that a final SDAP data PDU associated with the first QoS flow has been transmitted on the first DRB. The SDAP control PDU is then transmitted via the first DRB. In another example, upon detecting a mapping reconfiguration of a first QoS flow from a first DRB to another DRB, an end marker parameter is set in an SDAP header of a first SDAP data PDU received from an upper layer after the mapping reconfiguration indicating that the first SDAP data PDU is a final SDAP data PDU associated with the first QoS flow transmitted on the first DRB.

A method and apparatus for non-terrestrial network beam switching is provided. A non-terrestrial network base station includes a transmitter configured to transmit downlink data to user equipment and a receiver configured to receive uplink data from the user equipment. A channel bandwidth of the non-terrestrial network base station is divided into a plurality of bandwidth parts respectively corresponding to a plurality of geographic areas, and each bandwidth part is respectively associated with a satellite beam. When the user equipment is located in a first geographic area, the transmitter transmits the downlink data to the user equipment over a corresponding first bandwidth part. After the user equipment transitions from the first geographic area to a second geographic area, the transmitter transmits the downlink data to the user equipment over a corresponding second bandwidth part of the plurality of bandwidth parts.

A wireless device activates a first uplink bandwidth part (BWP) of a first cell. A beam failure of a second cell is detected. The wireless device switches, based on the first uplink BWP not being configured with one or more beam failure recovery resources for the second cell, from the first uplink BWP to a second uplink BWP, of the first cell, configured with the one or more beam failure recovery resources. An uplink signal indicating the beam failure is transmitted via the second uplink BWP.

A wireless device activates a first uplink bandwidth part (BWP) of a first cell. A beam failure of a second cell is detected. The wireless device switches, based on the first uplink BWP not being configured with one or more beam failure recovery resources for the second cell, from the first uplink BWP to a second uplink BWP, of the first cell, configured with the one or more beam failure recovery resources. An uplink signal indicating the beam failure is transmitted via the second uplink BWP.

A method of performing communication, by a user equipment (UE), in a wireless communication system, the method including receiving a radio resource control (RRC) message including a handover command, identifying whether a security key is updated based on the RRC message, and performing a packet data convergence protocol (PDCP) process based on a bearer type and a result of the identification.

A method of performing communication, by a user equipment (UE), in a wireless communication system, the method including receiving a radio resource control (RRC) message including a handover command, identifying whether a security key is updated based on the RRC message, and performing a packet data convergence protocol (PDCP) process based on a bearer type and a result of the identification.