Patent ID: 8594105

Claim:
A method for providing access to IMS services, wherein the method is carried out by a radio access network (RAN) that provides service in at least one coverage area, the method comprising: a first RAN component sending a registration message to an IMS network in order to register the first RAN component with the IMS network, wherein the IMS registration message provides an IP address at which to register the first RAN component; the first RAN component receiving a service request from a first access terminal, wherein the first RAN component is a serving RAN component for the first access terminal; and in response to receiving the service request, the first RAN component engaging in an IMS service on behalf of the first access terminal, wherein engaging in the IMS service on behalf of the first access terminal comprises sending the IMS network a first initiation message for a session event, wherein the first initiation message comprises: (i) a field that identifies the first access terminal and (ii) a field that includes an IP address of a second RAN component that serves a target access terminal; wherein the first RAN component is a different RAN component from the second RAN component, wherein the target access terminal is a second access terminal that is different from the first access terminal, wherein the service request comprises an identifier of the target access terminal, and wherein engaging in an IMS service on behalf of the first access terminal further comprises, during the session event: receiving a first message that comprises session data and a TO field that identifies the first access terminal, wherein the session message is received at the registered IP address of the first RAN component; and sending a second session message to the first access terminal, wherein the second session message provides the first access terminal with the session data from the first session message.