Method and apparatus for media independent handover

A method of performing a handover, the method comprising:

• receiving an INVITE request from an Internet protocol (IP) multimedia subsystem (IMS) client via a serving call session control function (S-CSCF), the INVITE request including a string “MIH services” and a unique identifier of the IMS client;
• creating a binding for the IMS client;
• establishing a media independent handover (MIH) session with the IMS client using a session initiation protocol (SIP);
• sending a handover command to the IMS client;
• receiving a handover result from the IMS client;
• receiving a RE-INVITE request or a REFER request from the IMS client, the RE-INVITE request and the REFER request including a string “MIH services” and a unique identifier of an IMS client;
• and
• updating the binding.

A wireless transmit/receive unit (WTRU) for performing a handover, the WTRU comprising:

• a transceiver;
• a processor configured to establish a session for IP-based service with a communication peer using a session initiation protocol (SIP);
• the processor configured to establish a media independent handover (MIH) session with an MIH application server using an SIP and perform a handover so that the session for IP-based service is resumed after the handover;
• and
• the processor configured to exchange an MIH message with the MIH application server over an IP, wherein the MIH session is established by sending an INVITE request to a proxy call session control function (P-CSCF) and a RE-INVITE request or a REFER request is sent to the MIH application server after handover to resume the session for IP-based service, the INVITE request, the RE-INVITE request and the REFER request including a string “MIH services” and a unique identifier of an IMS client.

A media independent handover (MIH) application server for supporting a handover, the MIH application server comprising:

• a receiver for receiving an INVITE request from an Internet protocol (IP) multimedia subsystem (IMS) client via a serving call session control function (S-CSCF), the INVITE request includes a string “MIH services” and a unique identifier of an IMS client;
• a processor for creating a binding for the IMS client and establishing an MIH session with the IMS client, the processor is configured to update the binding based on a RE-INVITE request or a REFER request from the IMS client, the RE-INVITE request and the REFER request including a string “MIH services” and the unique identifier of the IMS client;
• and
• the processor for exchanging an MIH message for a handover with the IMS client over an IP.