DEREGISTRATION AND EMM PARAMETER HANDLING CONSIDERING ACCESS TYPE

A method of handling de-registration and EPS mobility management (EMM) parameter for 3GPP when UE receives a de-registration request message via non-3GPP is proposed. There is an access type in the de-registration type IE in the de-registration request message. In one novel aspect, a UE handles EMM parameters of the de-registration procedure depending on the received access type in the de-registration type IE. Upon receiving a DEREGISTRATION REQUEST message, if the de-registration request is for 3GPP access or for 3GPP access and non-3GPP access, the UE performs a local release of the PDU sessions over 3GPP access and non-3GPP access, if any. Based on the 5GMM cause, UE also handles the corresponding EMM parameters including EMM state, EPS update status, 4G-GUTI, last visited registered TAI, TAI list, eKSI and attach attempt counter.