Narrowband Interference Suppression Using Undecimated Wavelet Packet Transform

In Direct Sequence Spread Spectrum (DSSS) systems, the undecimated wavelet packet transform (UWPT) can be effectively utilized to suppress narrowband interference. UWPT represents an advanced signal processing technique that decomposes signals into multiple frequency sub-bands while maintaining the original sampling rate through omission of downsampling operations. This approach enables detailed analysis and processing of each sub-band component, allowing for selective attenuation of interference-dominated frequency regions. The implementation typically involves applying wavelet packet decomposition trees with full frequency resolution, where interference detection algorithms can identify contaminated sub-bands based on energy thresholding or statistical analysis. Subsequent processing may employ soft-thresholding techniques or sub-band zeroing for interference suppression, while inverse UWPT reconstructs the cleaned signal. This methodology significantly enhances feature extraction capabilities and substantially reduces narrowband interference impact in DSSS systems. The technique proves particularly valuable for improving system performance and reliability in high-noise environments, as it preserves temporal resolution while offering superior frequency localization compared to conventional wavelet transforms. Consequently, employing UWPT in DSSS systems effectively enhances anti-interference capability and overall system performance through optimized time-frequency analysis and targeted interference cancellation.