重叠变换在扩频通信系统抗干扰中的应用

为了抑制扩频通信系统中的窄带干扰，提出了利用重叠变换（LT）进行变换域抗干扰处理，重叠变换的基函数长度可为子带数的偶数倍，对给定的滤波器带宽，重叠变换由于对输入信号进行重叠处理，故具有比块变换（BT）更大的阻带衰减性能，首先把接收信号映射到重叠变换域，然后进行变换域滤波，系统的性能由比特错误率（BER）来衡量，结果表明，该系统的BER特性远优于块变换，并且系统性能不随干扰频率和干扰带度的变化而改变，易于实时实现。

Narrow-Band Interference Excision in Spread Spectrum Communication Systems Using Lapped Tranform

In order to mitigate the narrow band interference in spread spectrum communications systems, lapped transform (LT) is used to tranform the received data signal to the transform domain wherein excision is performed. The lengths of the block transform basis vectors are limited to the number of transform domain cells, whereas the LT basis vectors are not restricted. They have length L that is equal to some even integer multiple of number of the bins, so LT typically yields improved stopbank attenuation in the frequency domain for a given filter bandwidth. System performance is evaluated by bit error rate (BER). The results demonstrate that transform domain excision technique based on LT can mitigate narrow band interference and be implemented in the hardware in real time.