Method and system for transferring user equipment in mobile communication system

A communication method comprising:

• receiving, by a terminal device from a source core network element, a transfer instruction carrying indication for transferring the terminal device through a tracking area update (TAU) process;
• and
• sending, by the terminal device to an access network device, a transfer request in response to the transfer instruction, wherein the transfer request indicates the access network device to select a target core network element for transferring the terminal device to the target core network element.

A communication method comprising:

• receiving, by an access network device from a terminal device, a transfer request indicating the access network device to select a core network element;
• and
• selecting, by the access network device in responsive to the transfer request, a target core network element for transferring the terminal device to the target core network element, wherein the target core network element is different from a source core network element.