A spatial and spectral detection approach for primary user interference mitigation in cognitive radios

The objective of cognitive radio (CR) is to allow utilization of unused frequency bands allocated to Primary Users (PUs) by Secondary Users (SUs) while maintaining negligible interference to PUs. This paper proposes a method for interference avoidance to PUs by combining beamforming based spatial signal processing and compressed sensing technique with Fast Filter Bank based spectral signal processing. Simulation results show that if a frequency band for SU is selected such that it is adjacent to a PU, with the aid of diversity gained from spatial signal processing, the interference by SUs to PUs can be further reduced by at least 20dB.