Patent ID: 9232390
Filing Date: 2016-01-05
CPC Classification: H04J,H04L,H04W

Claim Text:
1. A method of creating a derived radio base station key in a source radio base station of an Evolved Universal Mobile Telecommunications System Terrestrial Radio Access Network (E-UTRAN) cellular radio system in a connection with a User Equipment (UE) being connectable to the cellular radio system, said method comprising: determining, by the source radio base station, that a set of data comprises an E-UTRAN physical cell identity specific to a particular target cell associated with a target radio base station of the cellular radio system, said physical cell identity known to both the UE and the source radio base station; creating, by the source radio base station, the derived radio base station key based on the set of data and an existing cryptographic key used for communication between the UE and the source radio base station; transmitting, by the source radio base station, the derived radio base station key to the target radio base station, said derived radio base station key being used during a handover of the user equipment between the radio base station and the target radio base station or during a reconnection of the user equipment to the cellular radio system.