Volterra Filter Application in Ds-ss Receiver for Narrowband Interference Suppresion

The direct sequence spread spectrum (DS-SS) transmission system offers a promising solution to an overcrowded frequency spectrum amid growing demand for mobile and personal communication services. The overlay of DS-SS signals on existing narrowband users implies strong interference for DS-SS systems. In this paper, it will be shown how the application of linear and non-linear estimators in the DS-SS receivers can suppress this interference. In our consideration, Wiener filters (WF) and Volterra filters (VF) will be used as the estimators. These filters will be included between demodulator and despreading stage of a conventional receiver. Then, the received signal is passed through the estimator, which suppresses the narrowband interference prior to detection. In order to demonstrate the ability of discussed DS-SS receivers to suppress interference, a number of computer experiments will be done. The results of the experiment will show that the application of VF in DS-SS receivers can outperform the WF application or DS-SS receivers based on simple application of matched filter (MF) in a significant way.