Time-varying interference spectral analysis for Cognitive UWB networks

The potential interference from and to nearby wireless networks makes coexistence a crucial task in the design of Ultra Wide Band (UWB) systems. UWB radio technology may surely benefit from the use of Cognitive Radio (CR) techniques, implementing collaborative coexistence schemes. In this work, we consider a network formed by self-organizing nodes that operate according to the UWB principle. A Conscious Node (CNode) acts as the coordinator of the network and implements cognitive rules. Spectrum sensing is necessary for the CNode to be aware of the RF context and of network state. We provide an analysis method for the internal UWB interference experienced at the CNode receiver, by making use of the short-term Fourier transform based on windowing. We show that by adopting particular windows, such as the Blackman window, specific characteristics of the sensed interference spectrum may be highlighted. This work provides a first step towards reliable models for network spectral evolution that may provide the basis for advanced predictive and cognitive mechanisms.