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Intermodulation products arise as a result of low noise amplifier (LNA) and mixer non-linearities in wideband receivers. In the presence of strong blockers, the intermodulation distortion can deteriorate the spectrum sensing performance by causing false alarms and degrading the detection probability.We theoretically analyze the impact of third-order non-linearities on the detection and false alarm probabilities for both energy detectors and cyclostationary detectors under front-end LNA non-linearities.We show that degradation of the detection performance due to nonlinearities of both energy and cyclostationary detection is strongly dependent on the modulation type of the blockers. We then propose two DSP-enhanced receiver architectures to compensate the impact of nonlinearities. The first approach is a post-processing technique which compensates for nonlinearities effect on the test statistic by adapting the sensing time and detection threshold. The second approach is a pre-processing method that compensates by correcting received samples prior to computing the test statistic. This approach

As a result of wideband analog front-end, wideband spectrum sensing techniques are prone to suffer from RF nonlinearities. Intermodulation products due to strong subbands or carriers stemming from low noise amplifier nonlinearities, can easily degrade the spectrum sensing performance by causing false alarms and degrading the detection probability. We analyze the effects of third-order nonlinearities on both energy detectors and cyclostationary detectors under front-end nonlinearities. We show that the presence of strong blockers in the wideband channel can substantially degrade the sensing performance of both detectors, and energy detectors loose their advantage over cyclostationary detectors. Then, we propose an adaptive interference cancellation algorithm to compensate for the effect of the blockers at any subband of interest. The obtained results also show that when compensation is enabled, cyclostationary detector is more robust to moderate blocker signal levels than the corresponding energy detector.

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