WFRFT Precoding for Narrowband Interference Suppression in DFT-Based Block Transmission Systems

In this letter, we present a new approach to narrowband interference (NBI) suppression utilizing the weighted-type fractional Fourier transform (WFRFT) as a precoding scheme in the DFT-based communications systems. The proposed scheme can degenerate into a single carrier (SC) or a multi-carrier (MC) frequency division multiple access block transmission system by means of WFRFT parameter selection, which also leads to a variation of residual energy distribution of NBI following a frequency domain avoidance strategy. By virtue of parameter optimization of the WFRFT, the proposed system can outperform both SC and MC systems with regards to NBI suppression.