Adaptive subband transforms in time-frequency excisers for DSSS communications systems

A smart time-frequency exciser for DS-SS communications is proposed in this correspondence. This technique utilizes the concept of uncertainty in time-frequency analysis of signals. It brings the novel concept of domain switchable signal processing. Hence, the adaptive time-frequency (ATF) exciser has the capability of deciding the domain of the interference cancellation. Additionally, adaptive subband transforms are utilized for frequency domain excision. For time-domain excision, the ATF excision algorithm utilizes a sliding time window to reject the nonstationary, pulsed (time-localized) interference. It is shown that the proposed adaptive time-frequency exciser-based DS-SS communications receiver drastically outperforms the existing systems. Its performance is nearly optimal and very robust to the inter and intradomain variations of the undesired signal.