New Thresholding Technique in DCT Domain for Interference Mitigation in GNSS Receivers

The presented method is a DCT mitigation thresholding technique (DCT-MTT) for narrowband interference reduction in Global Navigation Satellite System (GNSS) receivers. First, the received signal immersed in an Additive White Gaussian Noise (AWGN), is multiplied, in time domain, (sample by sample) by a Tukey window of the same length. Then, the DCT transform is applied. Next, the transformed signal is divided in non-overlapped packets. Each one can be viewed as a non-interfered packet (if it has roughly the same variance as the estimated unknown variance of the AWGN) that must be conserved, or considered as an interference packet (if its variance is significantly greater than the variance of the AWGN) that should be thresholded. The conservation (or inversely the thresholding) of a packet is achieved by the use of DONOHO' s Universal-Threshold apart from that the variance is estimated based on the statistical sampling theory. The Final step consists in the application of the inverse DCT to obtain a good approximation of the received interference-less signal. The results obtained from several simulations confirm that the suggested strategy outperforms, in term of signal quality restoration, the conventional methods.