A cognitive system for future-proof wireless microphones: Concept, implementation and results

Since several years, `cognitive radio' is given much attention in research and is seen as a future technology in communications. In this paper a cognitive radio system for Program Making and Special Event (PMSE) devices (e.g. wireless microphones) is presented and the results of a field test are discussed. First, we outline the challenges which the PMSE industry has to cope with and how changes in regulatory and the digital dividend in the TV UHF band has impact on the operation reliability of PMSE devices. Afterwards, a system is presented that uses cognitive radio techniques to ensure the high audio quality requirements and interference free operation of PMSE devices under the previously mentioned circumstances. Beside a general overview over the developed system we focus on a distributed spectrum sensing network as part of the cognitive information acquisition to monitor the current spectrum situation. The data is used by the cognitive engine to detect potential interferers and to trigger operation parameter changes (e.g. frequency or transmit power) of the PMSE devices to avoid link quality degradation. We present the built-up sensor nodes for the spectrum measurement and the developed software to control the sensor nodes and to preprocess the measured data. Finally, the results, collected with the field test platform in the fair-ground of Berlin, show convincingly how the developed cognitive system makes PMSE devices future-proof.