Date Added: Oct 2010
Secondary wide-band users have to guarantee that they will not disturb the in-band narrow-band primary users with allocated spectrum. There are techniques proposed to limit the leakage power of secondary wide-band users in the specified in-band narrow bands. Active Interference Cancelation (AIC) can flexibly solve this problem in the digital domain and hence remove the need for extra analog hardware. The main challenge is that the final depth of a nulled band is severely degraded by RF impairments such as PA non-linearity, phase noise, and I/Q mismatch. In this paper, the authors investigate the effect of I/Q imbalance on the performance of active interference cancelation techniques.