Interference suppression in spread spectrum systems

The interference immunity of a spread spectrum digital communication system corrupted by interference can be significantly enhanced by excising the interference prior to cross correlation of the received signal with the possible transmitted reference signals. In this paper we treat methods for excising narrowband (partial band) and broadband (impulsive) interference in direct-sequence and frequency-hopped spread spectrum systems. Excision methods based on linear prediction and nonlinear filtering algorithms are shown to be particularly effective for direct-sequence spread spectrum systems corrupted by narrowband interference. We also consider nonlinear excision methods for frequency-hopped spread spectrum systems corrupted by narrowband interference and direct-sequence spread spectrum systems corrupted by broadband (impulsive) interference