The effect of a narrowband interference rejection filter on coarse acquisition in direct sequence spread spectrum

The performance of a direct sequence spread spectrum system using a linear prediction filter for interference suppression is given when narrowband Gaussian interference is present at the input. The performance of this system is compared to that of a similar acquisition system using transform domain processing techniques to implement a notch filter. When the interference bandwidth is small, the linear prediction filtering technique is shown to be superior, providing good performance over a wide range of the ratio of interference-power-to-signal-power (J/S). At larger interference bandwidths, it is shown that the transform domain processing technique is better than the linear prediction technique, but good performance levels can only be achieved over a limited range of J/S. Both the linear prediction filter (LPF) and transform domain processing (TDP) based acquisition systems, and the nature of the input signal, are described