US 5440613 Architecture for a cellular wireless telecommunication system
ABSTRACT – This invention relates to a method and apparatus for offering wireless telecommunication service. A switch such as an automatic Private Branch Exchange (PBX), equipped to communicate with Integrated Services Digital Network (ISDN) station sends ISDN signaling messages to and receives ISDN signaling messages from a protocol converter. The protocol converter, which also communicates with a wireless cell site, converts messages between the ISDN protocol and a protocol for communicating with the wireless cell site. The cell site sets up wireless connections to a mobile station, essentially in its prior art mode, and the PBX sets up connections to the cell site essentially in its prior art ISDN station control mode. The system can also hand off calls from one cell site to another connected to the same PBX, using the protocol converter to generate and distribute the locate request messages. The system can further process roamers by allowing them to register locally and by directly connecting intra-system traffic to such roamers.
This invention relates to wireless telecommunication systems and, more specifically, to architecture for small growable cellular wireless telecommunication networks.