Contributions on the filtering of continous wave interferences in CDMA communications systems
Alexandru Rusu, Carmen Voicu, Cristian Lucian Stanciu · 2014
The paper deals with the domain of CDMA communications systems affected by narrowband interferences, noise and flat fading. The spectrum used by some CDMA wireless systems is frequently utilized by other systems and the probability of radio-frequency interferences is relatively high in the vicinity of airports, broadcast towers and office buildings. This work researches the performances of several filtering techniques, in the presence of radio-frequency continuous wave interferences. The transmitted information is estimated using a multiuser detector based on POCS algorithm. We employ two main filtering methods (notch filtering and zeroing), that are adaptive and that can find and eliminate multiple CW interferences from the data signal. An implementation of an appropriate communications system is presented. A comparison of the performances of the filtering techniques is made and several conclusions are drawn.