Spectrum monitoring scheme for filter bank based cognitive radios

This paper focuses on the spectrum monitoring problem, i.e., detecting reappearing primary users during secondary transmissions in cognitive radio systems. The filter bank multicarrier (FBMC) concept is used as the basis as it facilitates simultaneous spectrum sensing and reception of secondary transmissions using the same device. With FBMC it is possible to support, in a spectrally efficient manner, narrow subcarrier-wide gaps in the spectrum of the transmitted signal for monitoring purposes. Such scheme allows fast reaction to reappearing primary users and it needs minimum amount of coordination between independent secondary systems operating in the same frequency band. We analyze the effect of the filter bank frequency response on energy detection based spectrum sensing. We also evaluate the impact of spectral regrowth due to transmitter power amplifiers, which is a critical issue in the proposed scheme.