| CPC H04W 60/04 (2013.01) [H04W 8/183 (2013.01); H04W 12/106 (2021.01); H04W 72/20 (2023.01); H04W 84/042 (2013.01)] | 13 Claims |

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1. An operation method of user equipment (UE), comprising
transmitting an attach request message;
receiving a response message,
wherein if the response message is an attach accept message and if the attach accept includes radio access technology (RAT) utilization control information, the RAT utilization control information is for current PLMN and its equivalent PLMN; and
if the response message is an attach reject message, if the attach reject message includes the RAT utilization control information and if the attach reject message is successfully integrity checked, storing the RAT utilization control information together with a PLMN identity of a current PLMN in a list of PLMNs with associated RAT restrictions.
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