Method and apparatus for prioritizing LTE cells in wireless communication system supporting ENDC (E-UTRAN NR dual connectivity)

A user equipment (UE) in a wireless communication system supporting Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN) New Radio (NR)-Dual Connectivity (ENDC), the UE comprising:

• a communication interface;
• and
• a processor configured to:
• receive system information comprising information on an NR band list supported in the ENDC through the communication interface,
• identify, based on the system information, NR bands supported at Long Term Evolution (LTE) frequencies of LTE bands in a most recently used (MRU) LTE frequency list of the UE,
• prioritize the LTE frequencies in the MRU LTE frequency list, based on the supported NR bands and an ENDC capability of the UE, and
• perform a cell selection based on the prioritized LTE frequencies in the MRU LTE frequency list,
• wherein the ENDC capability of the UE indicates at least one NR band supported by the UE for each of the LTE bands supported by the UE, and
• wherein the LTE frequencies in the MRU LTE frequency list are prioritized based on whether the supported NR bands match the ENDC capability of the UE,
• wherein the LTE frequencies in the MRU LTE frequency list comprise:
• first MRU LTE frequencies that do not support the at least one NR band of the ENDC capability of the UE,
• second MRU LTE frequencies supporting NR bands that do not match with the at least one NR band of the ENDC capability of the UE, and
• third MRU LTE frequencies supporting NR bands that match with the at least one NR band of the ENDC capability of the UE,
• wherein the third MRU LTE frequencies are prioritized over the first MRU LTE frequencies and the second MRU LTE frequencies,
• wherein the UE prioritizes at least two of combinations of LTE and NR bands based on peak throughputs of the at least two combinations of LTE and NR bands in a case that the UE detects at least one LTE cell supporting at least two of the combinations of LTE bands and NR bands, and
• wherein the peak throughputs are determined based on an available operator bandwidth corresponding to each of the combinations of LTE and NR bands.