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: This application provides a polar encoding method and apparatus. The method can include obtaining a basic sequence, where the basic sequence includes N0 subchannel numbers. The method can also include sequentially reading first subchannel numbers from the basic sequence, and sequentially reading 2m second subchannel numbers from the basic sequence starting from an Mth subchannel number based on the first subchannel number read each time; and adding q*N0 to each of the 2m second subchannel numbers to obtain 2m third subchannel numbers. Furthermore, the method can include constructing a polar code by using subchannels corresponding to the 2m third subchannel numbers as information bits. A polar code with another code length is constructed based on a sequence with a length of N0. A length of a polar code that needs to be stored is therefore reduced, which reduces complexity and is also easy to implement.

Abstract: This application provides a communication method and a communication apparatus. In the method, a source network device sends a request message to a target network device, where the request message is used to request to hand over a terminal device to the target network device. The source network device receives a response message from the target network device, where the response message indicates that handing over the terminal device to the target network device is allowed. The source network device sends first configuration information to the terminal device, where the first configuration information indicates artificial intelligence (artificial intelligence, AI) configuration information of the target network device. The source network device sends a first message to the terminal device, where the first message indicates to hand over the terminal device to the target network device.

Abstract: This application provides a communication method and a communication apparatus. Therefore, in a scenario in which a network device provides an artificial intelligence (artificial intelligence, AI) service for a terminal device, AI performance information of the network device is used as a basis for determining whether to access the network device, so that the terminal device subsequently accesses a network device with excellent AI performance information, and obtains an excellent AI service. In the method, the terminal device obtains AI model information of a first network device; and the terminal device determines AI performance information of the first network device based on the AI model information of the first network device.

Abstract: This application discloses example uplink power control methods and example apparatuses. One example uplink power control method includes receiving, by a terminal device, uplink power control information, wherein the uplink power control information comprises power adjustment information, and the power adjustment information is used to compensate for a power deviation caused by a transmission delay of a satellite communication link. The terminal device can then determine uplink transmit power based on the uplink power control information. An uplink signal can then be sent based on the uplink transmit power.

Abstract: Embodiments of this application provide a method and an apparatus for reporting location information. The method includes a terminal device determines that a trigger condition of a first procedure is satisfied. The first procedure is for determining a location area of the terminal device, and the trigger condition includes at least one of The terminal device switches the location area, a quantity of times that the terminal device switches the location area exceeds a first preset value; the terminal device has displacement, and the displacement exceeds a second preset value, a time interval since the last time the terminal device triggers the first procedure exceeds first time, or, the terminal device enters an idle state or an inactive state. The terminal device triggers the first procedure.

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 communication method and apparatus are provided to reduce interference between different types of satellites. The method is: A terminal device determines a satellite type corresponding to a first area, and the terminal device determines, based on the satellite type, whether to access a network device covering the first area. The terminal device determines, based on the determined satellite type corresponding to the first area, whether the network device can be accessed, so that a type of the network device accessed by the terminal device is consistent with the satellite type of the first area, and the terminal device can access only one type of satellite. When a plurality of types of satellites reuse a same frequency, the terminal device may receive signals of the plurality of types of satellites in the first area.

Abstract: A communication method and apparatus are provided. The method includes: A terminal device receives a first synchronization broadcast block (SSB) from a network device, where the first SSB indicates that a current network is in a coverage enhancement mode; then, the terminal device determines a target resource of first system information based on the first SSB; and finally, the terminal device receives the first system information from the network device based on the target resource. In the method, transmission of a plurality of repeated SSBs can be supported in the network coverage enhancement mode, and a quantity of transmitted system information blocks 1 (SIB1s) can be reduced, to reduce system overheads.

Abstract: The present disclosure relates to the communication field and discloses beacon sending and receiving methods and corresponding apparatuses for reducing hardware overheads and weights of a network device such as a satellite or a high-altitude platform and a terminal device such as a ground station. A method is provided that includes determining one or more subcarriers that are in a first frequency band, the first frequency band being one of N frequency bands included in a first beacon resource of the first send node, N being an integer greater than or equal to 1. The first send node sends a beacon signal on the one or more subcarriers. Correspondingly, a first receive node receives the beacon signal on the one or more subcarriers. The first receive node parses the beacon signal.

Abstract: Embodiments of this application provide a wireless communication method and apparatus. The method includes the following: a terminal device obtains a first model of a first network device. The terminal device receives first model indication information from a second network device. The first model indication information indicates a second model of the second network device. The terminal device sends second model indication information to the second network device. The second model indication information indicates an ensemble model of the first model and the second model. According to the methods provided in this application, the terminal device performs model ensembling, to implement knowledge transfer between network devices, thereby improving performance of a neural network model.

Abstract: The technology of this application relates to an information transmission method, an apparatus, and a system. The method includes user equipment receives first indication information sent by a first network device, where the first indication information includes a polarization method of a target cell, and the user equipment performs cell measurement on the target cell based on the polarization method of the target cell. According to the method, the user equipment can obtain the polarization method of the target cell before entering the target cell. In this way, when performing cell handover and reselection, the user equipment can enable, based on the polarization method of the target cell, only a port corresponding to the polarization method of the target cell, to receive a satellite signal, and perform cell measurement on the target cell, to complete cell handover and reselection procedures.

Abstract: This application provides a model training method and a related apparatus. In the method, a second communication apparatus receives a first neural network parameter of a first communication apparatus, and sends first indication information to the first communication apparatus when a correlation coefficient between the first neural network parameter and a second neural network parameter of the second communication apparatus is less than a first threshold. The first indication information indicates that the second communication apparatus is to participate in training of a first neural network model of the first communication apparatus. That the correlation coefficient between the first neural network parameter and the second neural network parameter is less than the first threshold indicates that the second neural network parameter makes a great contribution to convergence of the first neural network model.

Abstract: A satellite divides all beam positions in a coverage area of the satellite into K beam position groups based on population density of the beam positions in the coverage area of the satellite, where the K beam position groups are in a one-to-one correspondence with K broadcast beams of the satellite, K is an integer greater than 1, a quantity of beam positions included in a first beam position group is inversely proportional to population density in the first beam position group, the first beam position group is any one of the K beam position groups, and the first beam position group includes at least one beam position. The satellite sequentially performs beam scanning on the beam positions in the first beam position group by using a first broadcast beam corresponding to the first beam position group.

Abstract: The present disclosure relates to methods for indicating a direct current subcarrier and communication apparatuses. In one example method, a second communication apparatus may explicitly or implicitly indicate a location of a first direct current subcarrier and a location of a second direct current subcarrier to a first communication apparatus. The first direct current subcarrier is a direct current subcarrier corresponding to a transmit frequency used by the second communication apparatus. The second direct current subcarrier is a direct current subcarrier corresponding to a receive frequency used by the first communication apparatus.

Abstract: Embodiments of the application provide a method for rate matching in a wireless communication network. A device obtains K information bits and a target code length M of a polar code, determines, according to a minimum value of a set of values, a mother code length N, polar encodes the K information bits to obtain an encoded sequence of N bits, obtains a target sequence of M bits from the N bit encoded sequence, and outputs the M-bit target sequence.

Abstract: A terminal device obtains first indication information, where the first indication information indicates an ephemeris parameter of a first satellite at a first moment. The terminal device determines a position and a velocity of the first satellite at a second moment based on the ephemeris parameter of the first satellite at the first moment, where the second moment is after the first moment. In response to determining that an error of the position of the first satellite at the second moment is less than a first threshold and an error of the velocity of the first satellite at the second moment is less than a second threshold, the terminal device obtains second indication information, where the second indication information indicates an ephemeris parameter of the first satellite at a third moment, and the third moment is before the second moment.

Abstract: A first satellite obtains a parameter for determining an elevation angle for a departure service of the first satellite in a first serving cell. The first satellite sends first indication information to a terminal device, where the first indication information indicates the elevation angle for the departure service of the first satellite in the first serving cell in which the terminal device is located. The terminal device determines an elevation angle of the terminal device relative to the first satellite based on an ephemeris and location information of the terminal device. The terminal device determines the elevation angle for the departure service based on the first indication information, and compares the elevation angle for the departure service with the elevation angle of the terminal device relative to the first satellite, to determine whether to perform satellite reselection or handover.

Abstract: This application provides a signal transmission method and an apparatus. A network device broadcasts a navigation reference signal and a communication signal. A terminal device may determine its position information based on the navigation reference signal. A communication sequence in the communication signal and a navigation sequence in the navigation reference signal are coupled by using a same even-number-stage m-sequence, so that the terminal device is supported in completing an integrated communication and navigation function based on the broadcast signal.

Abstract: This application discloses a NB-IoT-based communication method and an apparatus, to evolve a NB-IoT communication technology into an NTN. The method is as follows: A terminal device generates an uplink signal, including a superframe which includes a synchronization sequence located in first duration of the superframe and a data frame located in second duration which is after the first duration, the synchronization sequence successively includes a first sequence repeated Ni times and a second sequence repeated N2 times, the second sequence is obtained by multiplying the first sequence by ?1, a part of consecutive sequences of the synchronization sequence are used as a first synchronization reference sequence that is obtained based on the second sequence repeated N2 times and one or more first sequences that are sorted from back to front in the first sequence repeated N1 times. The terminal device sends the uplink signal to a network device.