Handover control system, user terminal, signaling relay apparatus, and session control apparatus

摘要

The invention discloses a technique to adequately control a handover of a user terminal in a data communication network and to decrease the number of signalings. According to this technique, when address of a user terminal (UE (101)) is not changed after a handover, UE (101) transmits a session update signaling message to carry out update processing of application session to P-CSCF 1 (121) corresponding to a location before the handover via P-CSCF 2 (123) corresponding to a location after the handover. P-CSCF 1 (121) transfers a session update signaling message to S-CSCF/AS (125) by using setup of signaling relating to UE (100) before the handover. At S-CSCF/AS (125), the application session is updated by using registration information of UE (100) before the handover.

主权项

1. A method of updating an IP multimedia subsystem (IMS) session comprising:
when a user terminal performs a handover from a first access network to a second access network, wherein an address of the user terminal is not changed, and an entity supporting signaling of the IMS session is changed from a first Proxy Call Session Control Function (P-CSCF) to a second P-CSCF: the second P-CSCF receives an IMS session update message including a flag indicating that registration of a new IMS session is not made and an information element relating to the first P-CSCF from the user terminal, updates the IMS session update message, and transmits the IMS session update message to the first P-CSCF, the first P-CSCF and the second P-CSCF being entities supporting signaling of the IMS session; the first P-CSCF receives the IMS session update message from the second P-CSCF, and transmits the IMS session update message to a Serving Call Session Control Function (S-CSCF); and the S-CSCF receives the IMS session update message from the first P-CSCF, and updates the IMS session based on the IMS session update message using signaling of a setup of said user terminal, wherein the setup is performed before said handover.