Receiver window designs for radio frequency interference suppression

The DMT (discrete multitone) based VDSL (very high speed digital subscriber line)system is susceptible to interference due to radio frequency transmission. It is known that windowing at the receiver can reduce radio frequency interference (RFI). In this paper, we formulate the interference of individual tones and minimize the total interference. The optimal window can be obtained in a closed form. The proposed windows have faster roll-off in low frequency. As a result, fewer tones will be dominated by RFI. Simulations will be given to demonstrate the usefulness of the proposed design. We also see that not knowing the statistics of the interference source leads to only a minor degradation. Therefore, we can obtain very good suppression effect with interference-independent windows, which has the advantage that the window need not be redesigned when the interference changes.