Spectral redundancy exploitation in narrow band interference rejection for a PN-BPSK system

Different techniques have been proposed to excise narrow band interference from a direct sequence spread spectrum signal. One such technique is the frequency domain threshold exciser (THE). The THE estimates the spectrum of the received signal and weights the frequency bins appropriately. One disadvantage of this technique is that the power of the signal of interest (SOI) also gets reduced and thus the number of narrow-band interferers that can be excised is limited. This paper proposes a new technique which makes use of the spectral redundancy between the sidebands of the PN-BPSK signal to obtain a better estimate of the spectral energy of the SOI, by replacing corrupted spectral estimates with uncorrupted and correlated estimates. This spectral redundancy exploiting interference suppressor (SPREIS) provides improved performance over the THE with a small increase in the computational complexity. Simulation results are presented