Dispatcher workstation data communication in Nokia TETRA System

Abstract

Nokia TETRA System is a new cellular network developed by the Professional Mobile Radio business unit of Nokia Telecommunications. The system is based on the recent, fully digital TETRA standard and it is specifically meant to be used by public safety and security authorities. An essential part of the product is the dispatching system. A dispatcher workstation, a commercially available PC, belongs to the dispatching system offering versatile administration, monitoring and communication facilities via a windowed user interface. The purpose of this study is to design and implement a data connection between a dispatcher workstation and a radio network exchange. The connection is needed to make possible the required communication related signalling tasks. Furthermore the dispatcher has to be able to control the system and follow the situation in the field. Both of these functions demand a data connection. Several connections are presented and their advantages as well as disadvantages are viewed when the alternatives are considered. When the situation is analysed further it becomes evident that small resources and tight schedules demand a simple solution. Thus the readily available serial ports of the PC are chosen to be the interface to the infrastructure. A piece of software was implemented to utilise the selected interface. The software hides the physical communication from applications and offers the applications a transparent data transfer service. The performance tests of the implementation showed that the interface provides the applications with a sufficiently effective and reliable way to communicate. /Kir10