Abstract: A handover method and apparatus are disclosed. In some implementations, the method includes: determining a part of terminal devices to be handed over in a plurality of terminal devices in a staring area of a first beam; sending a first handover request message to a target satellite, where the first handover request message includes contexts of the part of terminal devices; and receiving a handover instruction sent by the target satellite based on the first handover request message, and sending the handover instruction to the part of terminal devices by using the first beam. The handover instruction includes handover parameters used for handing over the part of terminal devices. According to some implementations, the part of terminal devices in the plurality of terminal devices in the staring area may be handed over, so that a signaling storm can be avoided and communication performance can be improved.

Abstract: A satellite communication method and a network device are disclosed. A first network device learns of traffics of a plurality of satellite communications link or air interface resources allocated to a plurality of satellite base stations. The first network device sends identification information to a second network device, where the identification information indicates that a traffic of a satellite communications link reaches a specified threshold, or that an air interface resource allocated by a ground station to a satellite base station reaches a specified threshold. The second network device receives an identifier message, determines a to-be-linked satellite base station that has an idle resource, and sends, to the to-be-linked satellite base station, a second message including information about a generated beam of the to-be-linked satellite base station.

Abstract: This application provides a handover method and apparatus in satellite communications. The handover method in satellite communications in this application includes: obtaining, by a terminal device, ephemeris information of first satellite base stations, where the first satellite base stations are satellite base stations that cover the terminal device; determining, by the terminal device based on the ephemeris information, a destination satellite base station to which the terminal device needs to hand over; determining, by the terminal device based on the determined destination satellite base station, a first time at which the terminal device is to hand over to the destination satellite base station; and handing over, by the terminal device based on the determined first time, to a destination cell served by the destination satellite base station.

Abstract: Embodiments of this application relate to a cell handover method and apparatus, to determine a suitable access cell for a terminal in a cell handover process. The cell handover method is: A satellite receives a random access preamble that is of a first cell and that is sent by a terminal, where the random access preamble is used to determine terminal information used for cell handover; the satellite determines, based on the terminal information and cell attribute information that is of the satellite, a second cell most suitable for the terminal to access; and the satellite sends access information of the second cell to the terminal.

Abstract: This application provides a data packet processing method and apparatus, applied to a satellite communications system. An earth surface, space, and network space are divided based on a satellite constellation and an ephemeris of a satellite, and an identifier is allocated to each ground area, each space area, and each network that are sub-divisions of the earth surface, space and network space, to establish a fixed mapping relationship between the EID, the SID, and the NID. In addition, each satellite maintains mapping relationship information recording the mapping relationship. Unless a satellite joins the constellation or one satellite leave service, the mapping relationship recorded in the mapping relationship information does not need to be updated. Based on the mapping relationship information, a satellite may route a data packet, thereby reducing a large amount of signaling interaction caused by establishing and maintaining a routing table in the conventional manner.

Abstract: A media access control element (MAC CE) indicates a terminal device to enable or disable at least one hybrid automatic repeat request (HARQ) process, or the MAC CE requests a network device to enable or disable the at least one HARQ process. This provides a solution for dynamically controlling a HARQ function.

Abstract: Satellite cell reselection control methods and related devices are provided. One satellite cell reselection control method includes: determining a current location status of the user equipment; determining a satellite cell reselection control parameter set corresponding to the current location status; and the performing satellite cell reselection control of the user equipment based on the obtained satellite cell reselection control parameter set.

Abstract: Embodiments of this application disclose a communication method. The method includes: A terminal device sends a first message to a network device, where the first message includes one or more listening frequency indexes of one or more first tracking areas that are listened to by the terminal device within a first preset time period. The terminal device receives a second message including first registration area information from the network device. The first registration area information is determined based on the one or more listening frequency indexes. In the embodiments of this application, the accuracy of registration area information obtained by the terminal device can be improved, avoiding waste of communication resources caused by inaccurate registration area information received by the terminal device and improving communication resource utilization and practicality of the communication network.

Abstract: A method for selecting a cell in a non-terrestrial network (NTN) The method includes user equipment queries whether there is first prestored information and determines a frequency for preferential searching based on the first prestored information. The user equipment then determines values of a first decision factor, a second decision factor, a first weighting coefficient, and a second weighting coefficient in a first decision criterion. The user equipment searches for a cell according to the determined first decision criterion and selects a cell with the largest value of the first decision criterion is largest to camp.

Abstract: A handover method and apparatus are disclosed. In some implementations, the method includes: determining a part of terminal devices to be handed over in a plurality of terminal devices in a staring area of a first beam; sending a first handover request message to a target satellite, where the first handover request message includes contexts of the part of terminal devices; and receiving a handover instruction sent by the target satellite based on the first handover request message, and sending the handover instruction to the part of terminal devices by using the first beam. The handover instruction includes handover parameters used for handing over the part of terminal devices. According to some implementations, the part of terminal devices in the plurality of terminal devices in the staring area may be handed over, so that a signaling storm can be avoided and communication performance can be improved.

Abstract: A satellite communication method and a network device are disclosed. A first network device learns of traffics of a plurality of satellite communications link or air interface resources allocated to a plurality of satellite base stations. The first network device sends identification information to a second network device, where the identification information indicates that a traffic of a satellite communications link reaches a specified threshold, or that an air interface resource allocated by a ground station to a satellite base station reaches a specified threshold. The second network device receives an identifier message, determines a to-be-linked satellite base station that has an idle resource, and sends, to the to-be-linked satellite base station, a second message including information about a generated beam of the to-be-linked satellite base station.

Abstract: This application provides a preamble sequence configuration method, user equipment, and an access network device. The method in embodiments of this application includes: determining, by an access network device, preamble sequence information, where the preamble sequence information includes a message indicating a quantity of preamble sequences; and sending, by the access network device, the preamble sequence information to user equipment, where the preamble sequence information is used by the user equipment for random access.

Abstract: This application provides a preamble sequence configuration method, user equipment, and an access network device. The method in embodiments of this application includes: determining, by an access network device, preamble sequence information, where the preamble sequence information includes a message indicating a quantity of preamble sequences; and sending, by the access network device, the preamble sequence information to user equipment, where the preamble sequence information is used by the user equipment for random access.

Abstract: A D2D communication discovery method, an apparatus, and a system are disclosed. In an embodiment the D2D communication method includes acquiring, at an application layer, location information of a first user equipment and location information of a second user equipment, calculating a distance between the first user equipment and the second user equipment according to the location information of the first user equipment and the location information of the second user equipment and sending a D2D link establishment instruction to the first user equipment according to the distance between the first user equipment and the second user equipment so that the first user equipment and the second user equipment establish a D2D communication link.

Abstract: The present invention discloses a method and a relevant apparatus for achieving localized roaming of a mobile terminal. In the present invention, the mobile terminal sends real SIM card information to apply for a virtual SIM card to obtain a corresponding mobile terminal number of a roaming region, and registers user information to activate the virtual SIM card to serve as a calling party or a called party, so as to set up a called communication connection of a real SIM card. The mobile terminal applies for a virtual SIM card from a communication network of a roaming country to obtain a corresponding mobile terminal number of the roaming region through allocation, so that the user does not need to purchase a new SIM card in the roaming region, thereby saving the charges for purchasing the SIM card, ensuring a convenient operation and satisfying the demand of the user.

Abstract: A D2D communication discovery method, an apparatus, and a system are disclosed. In an embodiment the D2D communication method includes acquiring, at an application layer, location information of a first user equipment and location information of a second user equipment, calculating a distance between the first user equipment and the second user equipment according to the location information of the first user equipment and the location information of the second user equipment and sending a D2D link establishment instruction to the first user equipment according to the distance between the first user equipment and the second user equipment so that the first user equipment and the second user equipment establish a D2D communication link.

Abstract: The present invention discloses a method and a relevant apparatus for achieving localized roaming of a mobile terminal. In the present invention, the mobile terminal sends real SIM card information to apply for a virtual SIM card to obtain a corresponding mobile terminal number of a roaming region, and registers user information to activate the virtual SIM card to serve as a calling party or a called party, so as to set up a called communication connection of a real SIM card. The mobile terminal applies for a virtual SIM card from a communication network of a roaming country to obtain a corresponding mobile terminal number of the roaming region through allocation, so that the user does not need to purchase a new SIM card in the roaming region, thereby saving the charges for purchasing the SIM card, ensuring a convenient operation and satisfying the demand of the user.