Service registration method, terminal, and network side device

A service registration method, performed by a network side device, comprising:

• when a terminal accesses a first mobile network based on a first subscriber identity card, transmitting a VoWiFi registration message of a second subscriber identity card based on the first mobile network, wherein the terminal comprises a first subscriber identity card module and a second subscriber identity card module, the first subscriber identity card module is associated with the first subscriber identity card, and the second subscriber identity card module is associated with the second subscriber identity card,
• wherein before transmitting the VoWiFi registration message of the second subscriber identity card based on the first mobile network, the method further comprises:
• receiving a first handover request message sent by the terminal, wherein the first handover request message is used by the second subscriber identity card to request to perform a VoWiFi service;
• and
• sending a first handover response message to the terminal, wherein the first handover response message comprises a network address of an evolved packet data gateway (EPDG) network element of the network side device.

A terminal, comprising:

• a first subscriber identity card module associated with a first subscriber identity card;
• a second subscriber identity card module associated with a second subscriber identity card;
• a memory storing a computer program;
• and
• a processor coupled to the memory and configured to execute the computer program to perform operations comprising:
• accessing a first mobile network based on the first subscriber identity card;
• and
• transmitting a voice over wireless fidelity (VoWiFi) registration message of the second subscriber identity card based on the first mobile network,
• wherein before transmitting the VoWiFi registration message of the second subscriber identity card based on the first mobile network, the operations further comprises:
• sending a first handover request message to a network side device when no wireless local area network signal is detected and a mobile network signal parameter of the second subscriber identity card is less than a first preset value, wherein the first handover request message is used by the second subscriber identity card to request to perform a VoWiFi service;
• and
• receiving a first handover response message sent by the network side device, wherein the first handover response message comprises a network address of an evolved packet data gateway (EPDG) network element of the network side device.