A frequency domain time-dependent adaptive filter for interference rejection

The authors examine a type of adaptive filter called a time-dependent adaptive filter (TDAF). A TDAF can effectively deal with the cyclostationary nature of communication signals by changing periodically. It achieves a smaller mean-square error than conventional filter for cyclostationary signals. A frequency-domain TDAF is investigated, and it is shown that it is especially effective for interference rejection applications. Simulation results are presented, showing how cochannel QPSK signals can be separated.<>