Patent ID: 7496103

Claim:
A network interworking apparatus that enables mobile station roaming between wireless networks using different network communication protocols, the apparatus comprising: a first interface using a first protocol for sending and receiving control signal messages to and from a first wireless network, said first wireless network is a public wireless network having one or more public cells; a second interface using a second protocol for sending and receiving control signal messages to and from a second wireless network, said second wireless network is a private wireless network having one or more private cells within one or more of said public cells and having mobile stations that move among the private and public cells; a correlation unit including: a first software stack that processes the control signal messages of the first protocol including: a signal message encoder/decoder layer responsible for receiving and dispatching said control signal messages to and from said first wireless network, wherein the signal message encoder/decoder layer is located at the application layer and performs message formatting for use by lower layers of the first software stack; a second software stack that processes the control signal messages of the second protocol including: a signal message encoder/decoder layer responsible for receiving and dispatching said control signal messages to and from said second wireless network, wherein the signal message encoder/decoder layer is located at the application layer and performs message formatting for use by lower layers of the second software stack; and a protocol conversion unit that converts control signal messages from the first software stack to the second software stack format or converts control signal messages from the second software stack to the first software stack format based on an algorithmically predetermined mapping of first network messages with an equivalent second network messages and delivers said control messages to and from the first and second software stacks.