基于时变换域分布的码分多址复用系统干扰抑制技术

Interference Rejection in CDMA Overlay Systems Using Time-Transform Domain Distribution

基于时频分布能同时分析信号在时间域和频率域的特点 ,针对 CDMA Overlay通信系统中时变窄带干扰抑制问题 ,提出了一种广义的时频分布——时变换域分布 ,利用接收信号的时变换域分布获得干扰的瞬时频率 ,并据此设计相应的时变滤波器对干扰进行抑制 .在干扰为频率随时间变化的线性调频信号时 ,对时变干扰抑制方案进行了计算机仿真 .结果表明 ,该方案可以有效地抑制系统中的时变窄带干扰 .

The time-frequency distribution (TFD) can analyze non-stationary signals in both time and frequency domain. In this paper, a kind of general TFD - time-transform domain distribution (TTDD) was introduced into a narrowband interference rejection scheme in CDMA overlay communication systems. The instantaneous frequency (IF) that is estimated from the TTDD is used to design a time-varying filter to reject the non-stationary narrowband interference. The case of chirp signal with time-varying frequency is considered. The simulation results show that low bit error rate can be obtained by using the TTDD.