Rejection of pulsed CW interference in PN spread-spectrum systems using complex adaptive filters
Abstract
In this paper, the performance of direct sequence QPSK spread-spectrum systems using complex adaptive filters in the presence of pulsed CW interference is analyzed. Both adaptive prediction error filters and adaptive transversal filters with two-sided taps are considered. It is shown that the time constant of the tap weight adaptation in the interference off-interval is usually much greater than the time constant in the on-interval, and that this is beneficial for the system since it results in retaining the rejection property of the filter. Under steady-state conditions, the tap weights are calculated. Analytical expressions for the signal-to-noise ratio improvement under the least favorable interference condition are given. It is shown that the performance of the two-sided transversal filter is better than that of the prediction error filter.
- Publication:
-
IEEE Transactions on Communications
- Pub Date:
- January 1983
- Bibcode:
- 1983ITCom..31...10L
- Keywords:
-
- Adaptive Filters;
- Noise Reduction;
- Phase Shift Keying;
- Pseudonoise;
- Radio Frequency Interference;
- Spread Spectrum Transmission;
- Continuous Radiation;
- Prediction Analysis Techniques;
- Pulsed Radiation;
- Signal To Noise Ratios;
- Steady State;
- Transmission Efficiency;
- Communications and Radar