Frequency-Hopping Narrowband Interference Suppression in Spread-Spectrum Systems

This paper studies the suppression of frequency- hopping (FH) narrowband interference (NBI) in spread-spectrum (SS) systems. Existing NBI suppression algorithms focus on the case that the center frequency of the NBI is invariant and the performance degrades severely when the NBI is frequency-hopping. In this paper, an FH-NBI suppression algorithm is proposed based on the time- domain least mean square (LMS) prediction filter. The proposed algorithm detects the instant when the NBI hops from one frequency to another, and updates the filter coefficients using a novel method, which avoids the convergence time required in the conventional LMS algorithm. Both theoretical analysis and simulation results show that the proposed algorithm can suppress FH-NBI much more effectively than the existing algorithms.