The application of software radio techniques for airborne passenger telephony and future ATC communication systems

The need to develop cost effective airborne communication systems that make use of spectrum efficient waveforms, complex communication protocols and also provide multi-mode functionality is driving many avionics implementations towards software radio technology. The Airadio Division of GEC Marconi Electro-Optics Ltd. (ARD) has some eight years of experience in using this technology for airborne communications applications such as the European Terrestrial Flight Telephone System (TFTS) and the VHF Digital Link (VDL), which is being developed for future ATC communication requirements. Whilst there has been much discussion within industry regarding the application of software radio technology for integrated modular avionics (e.g. CNI avionics systems), complex radio system requirements are now beginning to drive this technology into federated systems. Traditionally a software radio approach has implied the use of leading edge wideband ADC, high speed DAC and powerful signal/data processing technologies. This paper shows how a less ambitious application of readily available technologies can still provide significant benefits. It provides an overview of the hardware and software technologies used in the design/development of two generations of TFTS product. The flexibility of the approach used for the first generation TFTS product hardware is illustrated by providing an overview of the updates incorporated for a VHF Datalink (VDL) prototype application. In mapping the VDL application onto the TFTS platform a number of issues associated with hardware and software design reuse have also been highlighted