A novel adaptive time-frequency excision technique for direct sequence spread spectrum communications

A novel, adaptive time-frequency (ATF) exciser for suppressing the interference in direct sequence spread spectrum (DSSS) communications systems is proposed. The adaptability of the proposed algorithm is two-fold. First, the domain of excision is decided. Then, for time-localized interference, excision is performed in the time domain. For a frequency-localized interference, an adaptive subband transform is employed. This joint treatment of time and frequency domains overcomes the performance limitations of the fixed transform-based excision algorithms. It is shown that the proposed ATF exciser-based DSSS receiver drastically outperforms the existing systems. Its performance is nearly optimal and very robust to the variations of the undesired signal