Parallel Multiband Spectrum Sensing in LTE-based Cognitive Radios

This paper creates a framework for spectrum sensing (SS) in localized Long-Term Evolution (LTE)-based cognitive radios. The framework includes the formulation of various SS problems based on different assumptions about the parameter space of the alternative hypothesis. In this scenario, a shared uplink LTE-based spectrum is divided into multiple frequencyorthogonal channels, enabling the parallel sensing of multiple primary user (PU) signals. The likelihood ratio test (LRT) and Rao principles are utilized to develop five parallel multiband SS algorithms. It is analytically demonstrated that four of the proposed detectors maintain a constant false alarm rate (CFAR) against noise variance uncertainty. In addition, a new thresholdsetting strategy is introduced to ensure that the non-CFAR detector maintains a false alarm rate below a predetermined level, resulting in a fixed level-of-test instead of a fixed size-oftest (CFAR test). Extensive simulations are conducted to validate the analytical results and compare the proposed algorithms with existing frequency-domain energy detector (FD-ED) and the cyclic prefix (CP)-based detector.