A Low Earth Orbit (LEO) satellite system is provided. The LEO satellite system includes a plurality of user equipment (UEs), a plurality of LEO satellites, and a ground station. The ground station obtains the required resources of each UE and the remaining resources of each LEO satellite. Based on the required resource of each UE and the remaining resource of each LEO satellite, the ground station determines to perform a handover to at least one UE of the plurality of UEs.

A Low Earth Orbit (LEO) satellite system is provided. The LEO satellite system includes a plurality of user equipment (UEs), a plurality of LEO satellites, and a ground station. The ground station obtains the required resources of each UE and the remaining resources of each LEO satellite. Based on the required resource of each UE and the remaining resource of each LEO satellite, the ground station determines to perform a handover to at least one UE of the plurality of UEs.

Disclosed are a handover method and a terminal device. The method includes that a first access network device triggers at least one of a terminal device or a second access network device to configure a second protocol stack; and before the first access network device triggers the at least one of the terminal device or the second access network device to maintain the sequence of the data packets of the terminal device by use of the second protocol stack, the first access network device sequentially processes data packets to be processed of the terminal device by use of a first protocol stack.

Disclosed are a handover method and a terminal device. The method includes that a first access network device triggers at least one of a terminal device or a second access network device to configure a second protocol stack; and before the first access network device triggers the at least one of the terminal device or the second access network device to maintain the sequence of the data packets of the terminal device by use of the second protocol stack, the first access network device sequentially processes data packets to be processed of the terminal device by use of a first protocol stack.

This disclosure relates to performing cell re-selection while in an inactive state in a cellular communication system. A wireless device may establish a radio resource control connection with a cellular base station. The wireless device may receive an indication to enter a radio resource control inactive state. The wireless device may perform cell re-selection while in the radio resource control inactive state. Cells that are in the current radio access network notification area of the wireless device may be prioritized over cells that are not in the current radio access network notification area of the wireless device when performing cell re-selection while in the radio resource control inactive state.

This disclosure relates to performing cell re-selection while in an inactive state in a cellular communication system. A wireless device may establish a radio resource control connection with a cellular base station. The wireless device may receive an indication to enter a radio resource control inactive state. The wireless device may perform cell re-selection while in the radio resource control inactive state. Cells that are in the current radio access network notification area of the wireless device may be prioritized over cells that are not in the current radio access network notification area of the wireless device when performing cell re-selection while in the radio resource control inactive state.

Methods and apparatus used to facilitate preparation of one or more target base stations for possible UE handoffs, e.g., conditional handoffs, which may or may not occur depending on whether or not various handoff conditions are satisfied are described. A handoff message, e.g., a conditional handoff message, including a validity time is generated and sent to each selected target base stations to which a UE may be handed off. The validity time indicates to the target base station a time window, e.g., a time duration for which the handoff target message is to be considered valid. In response to the handoff message, the target base station, receiving the handoff message, allocates resources to the UE and starts a countdown validity timer based on the indicated length of the validity time. When the validity timer expires without handoff to the target base station, the target base station releases the allocated resources.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine predicted mobility information associated with the UE that indicates a predicted route of the UE and one or more cells associated with the predicted route. The UE may transmit the predicted mobility information to a source base station. The UE may perform a handover of the UE from the source base station to a target base station based at least in part on the predicted mobility information. Numerous other aspects are described.

Embodiments of the present invention disclose a communication method, an apparatus, and a system. The communication method includes: receiving, by a terminal device, a context identifier sent by a second radio access network device, and sending, to a first radio access network device, a first message that includes the context identifier; receiving, by a core network device, a second message sent by the first radio access network device, and sending, to the second radio access network device, a message that includes the context identifier; and receiving, by the core network device, context information of the terminal device that is sent by the second radio access network device, and sending the context information to the first radio access network device. Therefore, communication between the first radio access network device and the second radio access network device is ensured, and working efficiency is improved.

Embodiments of the present invention disclose a communication method, an apparatus, and a system. The communication method includes: receiving, by a terminal device, a context identifier sent by a second radio access network device, and sending, to a first radio access network device, a first message that includes the context identifier; receiving, by a core network device, a second message sent by the first radio access network device, and sending, to the second radio access network device, a message that includes the context identifier; and receiving, by the core network device, context information of the terminal device that is sent by the second radio access network device, and sending the context information to the first radio access network device. Therefore, communication between the first radio access network device and the second radio access network device is ensured, and working efficiency is improved.