Providing security information to a mobile device in which user plane data and control plane signalling are communicated via different base stations

摘要

A communication system 1 is described in which user plane communication 11 and control plane communication 13, for a mobile communication device 3-2, 3-3, is split/divided between a base station that operates a small cell (e.g. femto-cell, pico-cell) 10-2, 10-3, and a macro base station 5-1, using separate component carriers in a Carrier Aggregation system. Macro base station 5-1 provides control signaling 13-2, 13-3, in the c-plane to mobile devices 3-2, 3-3, and pico base stations 5-2, 5-3, communicates user data 11-2, 11-3 in the u-plane. Appropriate security for the user plane and control plane communications is safeguarded by ensuring that each base station is able to obtain or derive the correct security parameters for protecting the user plane or control plane communication for which it is responsible. User plane security parameter may comprise a security key, KUPenc, for ciphering and/or deciphering user plane communication, derived using a further security key KeNB or KeNB* obtained from security information received from a network entity, e.g. Mobility Management Entity, MME. Control plane security parameter may comprise a security key, KRRCint for integrity protection of control plane communication. A security management module is configured for Authentication and Key Agreement, AKA.