Spectrum-aware frequency planning for professional wireless microphone systems

In recent years, the increasing spectrum demand of wireless applications had risen the need for an higher spectrum efficiency in general and for Programme Making and Special Events (PMSE) devices in particular. To this end, the cognitive radio paradigm has been proposed to overcome the limitations of static spectrum allocation. A dynamic frequency assignment, however, is quite challenging especially for non-linear analogue radio transmitters, like wireless microphones. In this paper, we motivate the need of a reliable dynamic frequency allocation process for PMSE systems that takes various internal and external constraints, such as intermodulation products and the given spectrum usage, into account. We present a fast algorithm for stochastic frequency planning and compare its performance with that obtained by the state-of-the-art heuristic approach in different interference scenarios. We show that the state-of-the-art approach is particularly well suited for selected interference scenarios. In those scenarios, our stochastic approach can achieve comparable results and even outperform the heuristic with a low probability. In common interference scenarios, our stochastic approach definitely outperform the heuristic, providing a general strategy that can adapt to the given spectrum situation. Finally, we propose an adaptive PMSE frequency planning process that combines the strength of both approaches.