Adaptive narrowband interference cancellation in overlaid CDMA systems using prior knowledge

Abstract

Narrowband interference cancellation techniques described in the literature often overlook the possibility of using prior information known to the receiver in a commercial radio environment to improve their performance. This paper examines an adaptive receiver which exploits knowledge about the narrowband interference which is readily available in commercial CDMA systems, namely its frequency and signal pulse shape, to remove it. The proposed algorithm uses only one adaptive weight per interferer, as opposed to a transversal filter interference canceller which would require many more. Attendant advantages include faster convergence, removal of the need for filter order selection and reduced distortion of the desired signal.