Patent ID: 7620400

Claim:
An Inter-System Message Delivery System, operable in a cellular communication network, for delivering a text message from a Message Service Center to a mobile subscriber station that has roamed out of the coverage area of a Serving Mobile Switching Center, comprising: cell paging means for identifying that a cell last accessed by said mobile subscriber station from the Serving Mobile Switching Center, which is not the subscriber's Home Mobile Switching Center, is unable to contact said mobile subscriber station; border cell identification means for determining that said cell last accessed by said mobile subscriber station is a border cell where the service area of said Serving Switching Center is juxtaposed to the service area of a cell of a Border Switching Center, which is not the subscriber's Home Mobile Switching Center; mobile subscriber station location determining means for transmitting a paging location request from said Serving Mobile Switching Center to said Border Mobile Switching Center to identify a present cell in said Border Mobile Switching Center in which said mobile subscriber station is operational; and message delivery means, responsive to said mobile subscriber station location determining means, for forwarding said text message from said Serving Mobile Switching Center which is not the subscriber's Home Mobile Switching Center, to said present cell in said Border Mobile Switching Center for transmitting said text message data to said mobile subscriber station.