New frequency-domain variable step size adaptive filter arithmetic for suppression of narrowband jammers

The constant step size frequency domain adaptive algorithm in direct sequence spread spectrum communication did not work well when the power of jammer changed. In order to overcome the shortcoming, based on studying the infulence of step factor μ and leak factor α on the suppression of narrowband jammer, a novel variable step size frequency-domain adaptive filtering arithmetic is proposed. This arithmetic is superior to constant step arithmetic, in environment that power of jammer changes, it can automatically adjust threshold B and has better suppression. Computer simulation results confirm the theoretical analysis and show the algorithm performance better than that of former algorithms.