Patent ID: 9060270
Filing Date: 2015-06-16
Classification: H04L,H04W

Abstract:
1. A method for establishing a security mechanism for an air interface link, comprising: deriving, by a mobility management entity, a shared key of an access link based on a root key and a Non-Access Stratum (NAS) count through a key derivation function (KDF), wherein the access link is an air interface link between a user equipment and a relay node, the relay node being communicated with an eNodeB through a relay link; performing, by the mobility management entity, security processing on the shared key of the access link according to a key shared by the relay node and the mobility management entity; sending, by the mobility management entity, over a network, the processed shared key of the access link to the relay node to enable the relay node to obtain the shared key of the access link based on the key shared by the relay node and the mobility management entity; deriving, by the mobility management entity, a second temporary key different from the processed shared key and based on the shared key of the access link; and sending, by the mobility management entity, the second temporary key to the eNodeB to enable the eNodeB to derive a shared key of the relay link using the KDF function where the second temporary key and a physical cell identity (PCI) of a coverage cell of the relay node are parameters, and to send the shared key of the relay link to the relay node.