US Patent 11553549 Multi-access PDU session state synchronization between UE and network

A PDU session status information element (IE) is used to bi-directionally synchronize the state of a multi-access (MA) Protocol data unit (PDU) session between UE and NW. In the downlink, the PDU session status IE is included in a 5GMM message sent from NW to UE over an access type, and it indicates the user plane resources are NOT established at NW side on the access type the 5GMM message is sent over. For MA PDU sessions having user plane resources established in the UE side only on the access type the 5GMM message is sent over, the UE performs a local release of those MA PDU sessions. For MA PDU sessions having user plane resources established in the UE side on both access types, the UE performs a local release on the user plane resources on the access type the 5GMM message is sent over.