MOBILE COMMUNICATION SYSTEM CAPABLE OF SUPPLYING A TELEPHONE NUMBER MAINTAINING SERVICE REGARDLESS OF A SERVICE PROVIDER CHANGE AND A METHOD THEREFOR, REGARDING TO CONTINUOUSLY USING AN EXSTING TELEPHONE NUMBER

摘要

PURPOSE: A mobile communication system capable of supplying a telephone number maintaining service regardless of a service provider change and a method therefor are provided to store NAM(Number Assignment Module) information including a provider change ID number, and to store service change information in a subscriber management DB, then to make a call through a changed provider network according to a call request signal, thereby continuously using an existing telephone number. CONSTITUTION: The first MSC(200) receives a call request signal including calling terminal information and called terminal information, detects the first service provider of a called terminal, and transmits the call request signal to a communication network formed by the first service provider of the detected called terminal. The second MSC(300) detects a changed service provider of the called terminal based on the called terminal information, and transmits the call request signal to a communication network formed by the detected service provider. The third MSC(400) transmits the call request signal to the called terminal to perform communication with a calling terminal through the communication network formed by the changed service provider.