Adaptive Mitigation of Multi-Narrowband Interferences in Impulse Radio UWB Systems Using A Spread Spectrum Sensing Technique

The coexistence among different systems is a fundamental issue in communications. Both coexistence analysis, i.e. measuring the mutual interference, as well as coexistence techniques, i.e. all the actions that guarantee the simultaneous use of the spectrum by different systems, have an impact on the performance of the system. This paper is focused on both these two aspects. In particular, we analyze the coexistence between ultrawide bandwidth (UWB) and narrow bandwidth (NB) systems emphasizing the role of spectrum sensing to identify and classify the NB interferers with highest powers. Direct Sequence (DS)-Time Hopping (TH) codes are then designed to mitigate the identified NB interference where notch frequencies are created in the UWB signal spectrum at bands where NB services operate. Finally, due to the severe multipath channel of UWB systems, a scenario where spectrum is sensed every symbol-duration to apply the mitigation technique on the identified NB interferer is presented.