Patent ID: 7292853

Claim:
A synchronization method of subscriber information for a roaming service of wireless private network systems in a multi-zone, the method comprising steps of: (a) performing initial system synchronization by initially synchronizing subscriber information of wireless terminals registered in each wireless private network system with associated wireless private network systems in the multi-zone at system initialization by updating the subscriber information in their respective subscriber information databases and into subscriber information databases of the associated wireless private network systems via a first network; and (b) if it is judged that a wireless terminal registered in a first wireless private network system moved to a service area of a second wireless private network system based upon location information contained in a location registration message received from the wireless terminal, updating, by the second wireless private network system, subscriber information of the wireless terminal into its subscriber information database by re-registrating the location information of the wireless terminal to synchronize the location re-registered subscriber information of the wireless terminal with associated wireless private network systems in the multi-zone via the first network, wherein the initial system synchronization step (a) comprises steps of: inspecting a synchronization flag of the subscriber information of each wireless terminal registered in the each wireless private network system to judge whether initial synchronization is necessary; if it is judged that the initial synchronization is necessary, transferring a synchronization-request message for synchronization of the subscriber information of the registered wireless terminal to each of the associated wireless private network systems via the network; and if synchronization-request reply messages informing synchronization completion through update of the subscriber information are received from the associated wireless private network systems, completing the initial system synchronization.