Digital linearization of direct-conversion spectrum sensing receiver

Reliable spectrum sensing ability is a key factor in cognitive radios. However, there are many aspects that impact the sensing reliability. One important aspect is impairments in the cognitive radio receiver hardware. Received signals tend to have high dynamic range which drives the receiver to the nonlinear zone. This may cause nonlinear distortion falling to the sensing band and therefore either triggers a false alarm or missed detection. This paper specifically focuses on the digital compensation of sensing receiver LNA nonlinearities which are typically the most significant sources of nonlinearity. The proposed method is able to notably remove nonlinear distortion from the received signal and thus spectrum sensing algorithms become more reliable. With the help of simulations, this is shown not only for a classical energy detector but also for a cyclostationary feature detector.