Method and apparatus for acquiring cell identifier in radio communication system

A method for supporting a source cell to acquire a cell identifier by an evolved packet core (EPC) in a radio communication system, the method comprising:

• determining whether a public land mobile network (PLMN) identifier (ID) (PLMN ID) in an evolved universal terrestrial radio access (EUTRA) cell global identifier (ECGI) of a new cell different from the source cell is included in a mapping table between a primary PLMN ID and a shared PLMN ID;
• and
• providing an X2 internet protocol (IP) address of the new cell to the source cell according to the determination results;
• and
• stopping providing the X2 IP address of the new cell, if the PLMN ID in the ECGI is not included in the mapping table.

A source cell apparatus in a radio communication system, the apparatus comprising:

• a receiving unit configured to receive information about a new cell from a user equipment (UE) in the source cell;
• and
• a control unit configured to:
• acquire an evolved universal terrestrial radio access (EUTRA) cell global identifier (ECGI) of the new cell from the UE, if it is determined based on the information about the new cell that there is no neighbor relationship with the new cell;
• determine whether a public land mobile network (PLMN) identifier (ID) (PLMN ID) in the ECGI is included in a mapping table between a primary PLMN ID and a shared PLMN ID;
• acquire an X2 Internet Protocol internet protocol (IP) address of the new cell from an evolved packet core (EPC) according to the determination results;
• and
• discard the information about the new cell, if the PLMN ID in the ECGI is not included in the mapping table.

An evolved packet core (EPC) that supports a source cell to acquire a cell identifier in a radio communication system, the EPC comprising:

• a control unit configured to:
• determine whether a public land mobile network (PLMN) identifier (ID) (PLMN ID) in an evolved universal terrestrial radio access (EUTRA) cell global identifier (ECGI) of a new cell different from the source cell is included in a mapping table between a primary PLMN ID and a shared PLMN ID;
• provide an X2 internet protocol (IP) address of the new cell to the source cell according to the determination results;
• and
• stop providing the X2 IP address of the new cell, if the PLMN ID in the ECGI is not included in the mapping table.