Abstract: A data transmission method includes obtaining a user equipment route selection policy (USRP) rule parameter of a started application, establishing a first protocol data unit (PDU) session corresponding to the started application with a network device through the modem module when no PDU session parameter matching the URSP rule parameter exists in the mapping table, adding an interface name of the first PDU session to the routing table, adding a mapping relationship between the session parameter of the first PDU session and the interface name of the first PDU session to the mapping table, and routing to-be-transmitted data of the started application to the first PDU session by using the interface name of the first PDU session.

Abstract: A method and an apparatus for determining radio access policy include implementation by a first network element that obtains a movement manner of a terminal device. The first network element determines a radio access policy of the terminal device based on the movement manner of the terminal device. The radio access policy is used to indicate at least one of a radio access technology (RAT) selection priority of the terminal device, a frequency selection priority of the terminal device, or a cell selection priority of the terminal device enabling the terminal device to access a proper RAT system, frequency, or cell.

Abstract: This application discloses a communication method. When determining that a network used to provide a service does not meet a transmission requirement of service data, a terminal device requests, from a PCF, an SMF, or an NWADF, to analyze a reason why the network does not meet the transmission requirement of the service data. The PCF, the SMF, or the NWADF obtains information used to recover a service, and sends the information to a device that performs a service recovery operation, for example, the terminal device or an access network device. The information used to recover the service is used to enable the network to meet the transmission requirement of the service data.

Abstract: This application provides a method and an apparatus for making an emergency call. The method includes: obtaining location information of UE; determining, based on the local information, whether the UE is located in a home country of an HPLMN of the UE; and when the UE is located in the home country of the HPLMN, if a predetermined condition is satisfied, initiating a VoWiFi emergency call by using an IMS APN of the HPLMN, where the predetermined condition includes: the UE has completed IMS registration, and a PLMN on which the UE camps includes no emergency APN. According to the method and apparatus for making an emergency call provided in this application, a VoWiFi emergency call success rate can be increased to some extent.

Abstract: A cell measurement method. According to the method, a terminal device determines that a first cell as a camped cell of the terminal device; and then determines that the terminal device is in a target environment. The terminal device further obtains a signal strength of the first cell and performs a measurement on a second cell when the signal strength of the first cell is less than a first threshold and greater than a second threshold. The second cell determined by the terminal device based on the target environment. The terminal device switches the camped cell of the terminal device from the first cell to the second cell when a measurement result of the second cell meets a handover condition.

Abstract: A registration method, a session establishment method, a terminal, and an access and mobility management function (AMF) entity, where the method includes: sending, by a terminal, a first message to the AMF entity, where the first message includes first information, first network slice selection information, and second network slice selection information, the first information includes information for requesting to establish a protocol data unit (PDU) session, the first network slice selection information is used by the AMF entity to select a first session management function (SMF) entity, and the second network slice selection information is used by the AMF entity to select a second SMF entity; and receiving, by the terminal, a second message from the AMF entity, where the second message includes second information, and the second information includes PDU session establishment accept information.

Abstract: A media service processing method, applied to an electronic device, includes providing, by an application running on the electronic device, a media service for a user, sending, to a server, request signaling requesting to send data of the media service to an intermediate storage unit, storing, in the intermediate storage unit, the data, moving the data from the intermediate storage unit to a target storage unit, wherein storage space of the intermediate storage unit is greater than storage space of the target storage unit, obtaining the data from the target storage unit, and playing the data.

Abstract: Embodiments of this application describe an inter-device communication method, a related device, and a system. The method includes a first device sending a first message. The first message includes one or more of the following parameters: a first parameter, a second parameter, and a third parameter. The first parameter is used to indicate that the first message is a message for announcing provision of an interactive business service. The second parameter is used to indicate an identifier corresponding to the interactive business service that can be provided by the first device. The third parameter is used to indicate a processing capability that can be provided by the first device for the interactive business service.

Abstract: Embodiments of this application provide a transmission path switching method and apparatus. When a transmission path is switched, a currently used data transmission path is not directly switched from a first transmission path to a second transmission path after the second transmission path is configured, but after it is further determined that a first condition is met, the currently used data transmission path is switched from the first transmission path to the second transmission path, to avoid data interruption in a process of switching a data transmission path of an application from the first transmission path to the second transmission path. This improves use smoothness of the application.

Abstract: The technology of this application relates to a method including, when a user equipment (UE) determines that a preset condition is met, the UE sends a session release request message or a session modification request message to a network device. The session release request message is used to request to release a first PDU session, the session modification request message is used to request to release a first quality of service (QoS) flow, and the first PDU session is one of existing PDU sessions in the UE. The preset condition includes at least one of: a quantity of existing PDU sessions in the UE reaching a first threshold; a quantity of data radio bearers (DRB)s associated with the existing PDU session in the UE reaching a second threshold; and a quantity of quality of service flows associated with the existing PDU session in the UE reaching a third threshold.

Abstract: In a network handover method disclosed in this application, when an electronic device accesses a first mobile network by using the first SIM card, the electronic device obtains network information of the first mobile network in a process in which the electronic device moves along a first route. When the electronic device predicts, according to the obtained network information of the first mobile network, that an exception is going to occur in the first mobile network, the electronic device accesses the second mobile network by using the second SIM card. In this technical solution, an electronic device having a dual SIM card can be handed over from a first mobile network to a second mobile network in advance when it is predicted that an exception is going to occur in the first mobile network, thereby reducing the possibility of frame freezing or network disconnecting when a user accesses the Internet.

Abstract: A circuit switched fallback (CSFB) method and apparatus, where a user equipment (UE) initiates a calling process, receives a first request from a first communications system, and after the UE is transferred to a second communications system and before the UE receives a first message from the second communications system, the UE determines that a voice call bearer cannot be set up in the second communications system, and initiates a CSFB in the second communications system, where the first message is used by the UE to determine that a call request has failed.

Abstract: Embodiments of this application relate to the field of communications technologies, and disclose a relay device selection method, and a user equipment, so that UE can select and update with an allowed S-NSSAI of the UE. The method may include: obtaining by UE, M pieces of first indication information, each indicates one allowed network slice of the UE; receiving by the UE, first messages sent by L relay devices, comprising N pieces of second indication information, wherein each indicates one allowed network slice of the relay device; and selecting by the UE, a random first relay device as a target relay device based on the M pieces of first indication information and the L pieces of first messages.

Abstract: An application processor sends a TCP packet to the modem, where the TCP packet is used by the modem to generate a wireless protocol data packet corresponding to the TCP packet, so that the modem sends the wireless protocol data packet to a base station. The application processor receives first status information from the modem, where the first status information is status information of the wireless protocol data packet or status information of the TCP packet. The application processor determines, based on the first status information, whether the TCP packet is successfully sent to the base station. If the TCP packet is successfully sent to the base station, the application processor starts a retransmission timer corresponding to the TCP packet. If the TCP packet is not successfully sent to the base station, the application processor sends the TCP packet to the modem again.

Abstract: A session management method by a terminal in which a network initiates a session deactivation procedure to deactivate one or more sessions of a terminal. After the terminal in an inactive mode establishes an RRC connection to a new second base station, the second base station indicates, through RRC connection reconfiguration, the terminal to delete related information of the to-be-deactivated session, or the second base station uses an RRC connection resume response message to carry an identifier of the one or more to-be-deactivated sessions, and the terminal deletes session-related information corresponding to the identifier of the one or more to-be-deactivated sessions. In this way, the terminal is enabled to process the related information of the to-be-deactivated session in a timely manner.

Abstract: A secondary cell group (SCG) side service processing method includes a master base station that configures a master cell group and a an SCG for a terminal device. In uplink and downlink data transmission processes, when link quality information of a serving cell in the SCG meets a first preset condition, the terminal device obtains link quality information of a neighboring cell of the serving cell determines, based on the link quality information, whether there is a better neighboring cell, and when there is no better neighboring cell, sends a first message to the master base station to enable the master base station to determine, based on the first message, whether to release the SCG.

Abstract: A data transmission method includes that when a preset condition is met, a first terminal device establishes a first Transmission Control Protocol (TCP) connection to an application server, and establishes a second TCP connection to an application client on a second terminal device; the first terminal device receives, through the first TCP connection, first service data from the application server; the first terminal device buffers the first service data; and the first terminal device sends the first service data to the second terminal device through the second TCP connection.

Abstract: Embodiments of this application relate to the field of communications technologies, and disclose a relay device selection method, and a user equipment, so that UE can select and update with an allowed S-NSSAI of the UE. The method may include: obtaining by UE, M pieces of first indication information, each indicates one allowed network slice of the UE; receiving by the UE, first messages sent by L relay devices, comprising N pieces of second indication information, wherein each indicates one allowed network slice of the relay device; and selecting by the UE, a random first relay device as a target relay device based on the M pieces of first indication information and the L pieces of first messages.

Abstract: Embodiments of the present application relate to the field of communications technologies, and provide a session management method and system, and a terminal. The method includes: when user equipment UE has a first protocol data unit PDU session, sending, by the UE, a service request message to an access and mobility management function AMF entity; receiving, by the UE, a first message sent by the AMF entity; and determining, by the UE based on the first message, to re-establish or modify the first PDU session. In the embodiments of the present invention, the UE sends the service request message to the AMF entity, and then the AMF entity sends, to the UE, the first message used to determine to re-establish or modify the first PDU session.

Abstract: A method for transfer between communications systems includes establishing at least one first data connection channel in a first communications system, selecting at least one second data connection channel from the at least one first data connection channel, where the second data connection channel is included in the first data connection channel and is certain to support transfer from the first communications system to a second communications system or is uncertain whether to support transfer from the first communications system to the second communications system, and transferring the second data connection channel to the second communications system when the terminal device has been transferred from the first communications system to the second communications system.