Patent ID: 8549293

Claim:
A method of establishing security association between heterogeneous networks at a mobile station, the method comprising: exchanging capability messages with a serving base station of a serving network, the capability messages including a parameter indicating whether to support an authorization policy between heterogeneous networks and a security negotiation parameter which indicates a security capability to be negotiated before an authorization procedure when a handover is performed between the heterogeneous networks; a first step of receiving information of neighboring heterogeneous networks from an information server, the information comprising security related parameters of a link layer which includes an encryption algorithm and an authorization method of the neighboring heterogeneous networks; a second step of transmitting a request message for requesting a serving network authentication server to transfer authentication related information to a target heterogeneous network where the mobile station intends to perform the handover among the neighboring heterogeneous networks, and for requesting security contexts used in the target heterogeneous network, wherein the request message includes an authorization result of the serving network authentication server for the mobile station and information about the mobile station; a third step of receiving the security contexts which includes authentication related information and key related information of the target heterogeneous network from the serving network authentication server; after receiving the security contexts, performing a link layer handover procedure with the target heterogeneous network without performing an authentication procedure with the target heterogeneous network; and performing a third layer handover procedure with the target heterogeneous network.