Digitally enhanced inter-modulation distortion compensation in wideband spectrum sensing

The wideband spectrum sensing is vulnerable to interferers and blockers due to inter-modulation distortion (IMD) that arises in nonlinear front-end. Traditional DSP-enhanced receivers use least mean squares (LMS) filters to mitigate IMD. We theoretically study the performance of LMS-based algorithm and give expression of its residual distortion power. We then propose a novel compensation algorithm that outperforms LMS. Compared with LMS, our algorithm improves the effective spurious-free dynamic range by 10 dB. In sensing signals under 0 dB SNR, receivers with our solution tolerate 5 dB stronger interferers than those adopting LMS.