Iterative threshold algorithm for narrow-band interference suppression

Narrow-band interference (NBI) suppression based on Fast Fourier Transform (FFT), in which interference suppression threshold plays a key role, is widely applied in spread spectrum communication system. However, the traditional fixed threshold is not suitable in time varying scenarios. To solve this problem this paper proposes an iterative threshold algorithm based on overlap window which can efficiently mitigate NBI. Furthermore, simplified calculation of the iterative threshold and the structure of its FPGA realization are given. Simulations illustrate the validity of this algorithm, which improves the signal-to-interference ratio (SIR) to 1.0484 dB from original SIR -30 dB.