Patent ID: 11917055
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 10:
11. A user equipment (UE), the UE comprising:
processing circuitry;
wherein:
the UE is arranged to establish a security key for protecting Radio Resource Control/User Plane traffic exchanged with a serving radio base station; and
the processing circuitry is configured to:
send a Non access Stratum (NAS) message containing a NAS service request to a mobility management entity (MME), the NAS message indicating a NAS uplink sequence number; and
derive the security key from at least said indicated NAS uplink sequence number and from a stored access security management entity-key shared with said mobility management entity, using a key derivation function taking the NAS uplink sequence number and the stored access security management entity-key as inputs.