Method and apparatus for inter-radio access network mobility

A method of a second base station in a wireless communication system, the method comprising:

• receiving, from a first base station, a message requesting an inter-radio access technology (RAT) handover from a cell of the first base station to a cell of the second base station, the message including inter-RAT measurement configuration information, a tracking area identity (TAI), an identifier of the first base station, and an identifier of the cell of the first base station, the inter-RAT measurement configuration information includes information on a duration in which the second base station is to collect measurement results and information on a frequency for which the second base station collects the measurement results;
• receiving measurements results of the frequency for the duration of collecting the measurements results by instructing a user equipment (UE) to measure the frequency after the inter-RAT handover to the second base station is performed successfully;
• identifying that the inter-RAT handover is unnecessary based on the collected measurements results;
• and
• transmitting, to the first base station, a handover report indicating that the inter-RAT handover is unnecessary, the handover report including the identifier of the cell of the first base station.

A first base station in a wireless communication system, the first base station comprising:

• a transceiver configured to transmit and receive a signal;
• and
• a processor configured to control the transceiver to:
• transmit, to a second base station, a message requesting an inter-radio access technology (RAT) handover from a cell of the first base station to a cell of the second base station, the message including inter-RAT measurement configuration information, a tracking area identity (TAI), an identifier of the first base station, and an identifier of the cell of the first base station, and
• receive, from the second base station, a handover report indicating that the inter-RAT handover is unnecessary after the inter-RAT handover to the second base station is performed successfully, the handover report including the identifier of the cell of the first base station,
• wherein the inter-RAT measurement configuration information includes information on a duration in which the second base station is to collect measurement results and information on a frequency for which the second base station collects the measurement results, and
• wherein the measurement results are received from a user equipment (UE) by instructing the UE to measure the frequency.

A second base station in a wireless communication system, the second base station comprising:

• a transceiver configured to transmit and receive a signal;
• and
• a processor configured to:
• control the transceiver to receive, from a first base station, a message requesting an inter-radio access technology (RAT) handover from a cell of the first base station to a cell of the second base station, the message including inter-RAT measurement configuration information, a tracking area identity (TAI), an identifier of the first base station, and an identifier of the cell of the first base station, the inter-RAT measurement configuration information includes information on a duration in which the second base station is to collect measurement results and information on a frequency for which the second base station collects the measurement results,
• control the transceiver to receive measurements results of the frequency for the duration of collecting the measurements results by instructing a user equipment (UE) to measure the frequency after the inter-RAT handover to the second base station is performed successfully,
• identify that the inter-RAT handover is unnecessary based on the measurements results, and
• control the transceiver to transmit, to the first base station, a handover report indicating that the inter-RAT handover is unnecessary, the handover report including the identifier of the cell of the first base station.