Question

高手们帮忙翻译一下！！谢谢谢谢！！

Abstract: This letter presents two preprocessing techniques for narrow-band interference (NBI) rejection in Time-Division-Duplex (TDD) CDMA systems. In the proposed methods, at the transmitter, by using Karhaunen-Loeve Transform and Discrete Fourier Transform, the transmitted power is set to zero in the directions of the eigenvectors that will be severely contaminated by NBI; and therefore less part of the transmitted energy will be polluted by NBI in channel. The processing is transferred from receiver to transmitter, and thus the complexity of the receiver is significantly reduced. It is assumed that channel state information can be estimated at the transmitter because in symmetric TDD systems each receiver in turn also acts as a transmitter.

Keywords: CDMA； narrow-band interference；pre-processing

1. Introduction
The performance of a CDMA communication system in the presence of narrow-band interference (NBI) can be improved by using processing techniques at receiver[1]. In recent years, several authors proposed the use of transform domain processing techniques at the receiver for NBI suppression by using different transforms such as discrete Fourier transform (DFT) and Karhaunen Loeve transform (KLT)[2]−[4].
On the other hand, a group of methods that were recently suggested for mitigating multiuser and intersymbol interference were based on preprocessing [5−6]. The general structure of a preprocessing method is shown in Fig. 1, where the data to be transmitted are given by the vector a, whereas the channel input is denoted as x. H and FRX denote the channel matrix and additional receiver processing, respectively. The goal is making FRX as simple as possible and the transferring complexity from receiver to transmitter. In contrast to the conventional methods, in the preprocessing techniques, the channel state information (CSI) is required at the transmitter side. This is naturally the case in symmetric Time-Division-Duplex (TDD) systems, where each receiver in turn also acts as a transmitter [5−6].
In this letter, we propose two transform-domain pre-processing techniques in transmitter in order to NBI suppression in CDMA communication systems. In the proposed methods, by using KLT and DFT, the energy of the transmitted signal is set to zero in spectrum bands where NBI exists. The results of our simulations show that because of not sending the energy in the area where the NBI presents, less information is polluted by the NBI in channel. By applying the proposed method, the receiver complexity is significantly reduced because the major part of the processing, which is needed for suppressing the NBI, would be moved from the receiver to the transmitter.

Answer 1

文摘:这封信提出了两种预处理技术,为窄带干扰排斥在Time-Division-Duplex(TDD)CDMA系统。在这个方法,利用Karhaunen-Loeve发射机、改造和离散傅立叶变换,发射功率设置为零的特征向量的方向,将会受到严重污染,NBI;因此少部份的发射能量将会受到NBI在通道。转移的处理,从而收发射机的复杂性,接收器明显降低。这是假定通道的状态信息,可以估计发射机由于在对称TDD系统各接收器反过来也作为一个发射器。
关键词:窄带干扰、CDMA、预处理

1。介绍
公司业绩CDMA通信系统中存在窄带干扰可提高加工技术在接收器[1]。近年来,已有提出利用变换域加工技术的接收器,采用不同的变换抑制诸如基于离散傅里叶变换(DFT)和Karhaunen Loeve变换(KLT−)[2][4]。
另一方面,一群方法,提出了一种在减轻最近和码间干扰是基于文本分类的预处理−)(5)。这个系统的总体结构的预处理方法图1显示的是,在给出的数据传输,而由矢量通道输入作为属性x。氢和FRX信道矩阵和额外用来接收处理。目标是使FRX尽可能简单和复杂的转移,从接收发射机。与传统的方法相比,在预处理技术,信道状态信息的发射机。要求这是自然地出现在对称Time-Division-Duplex(TDD)系统中,每个接收器反过来也作为一个变送器(6)−)。
在这封信里,我们提出两transform-domain预处理技术,以抑制器在CDMA通信系统。在这个方法的基础上,利用离散傅立叶变换,KLT和发送信号的频谱设置为零的乐队在NBI存在。结果表明,由于我们的模拟的能量在发送信号的地方,减少了信息NBI污染在通道。NBI应用该方法,接受者复杂度明显降低,因为绝大部分的处理,这是必需的,会抑制NBI是从接收者发送。