Method and System for Providing SIP based Instance Messaging Service for non-SIP based Mobile Station in IP Multimedia Subsystem, and Instance Messaging Proxy Serve for the same

摘要

The present invention provides a method and system for providing a SIP based Instance Messaging (IM), and an IM proxy server therefor. An IM proxy server for performing a proxy function in a mobile communication network is configured to provide an IM service between a mobile terminal lacking an SIP function and an IM server. Further, the IM proxy server converts an IM message received from the mobile terminal into a corresponding SIP message mapped thereto, transmits the SIP message to the IM server through a call session control server, converts an SIP message received from the IM server through the call session control server into an IM message recognizable by the mobile terminal, and transmits the IM message to the mobile terminal, thus providing the SIP based IM service to the mobile terminal lacking an SIP function.