平滑化的正交型Walsh函数的构造及在广带域扩谱通讯中的应用

Structure of Smoothing and Orthogonal Walsh Function and Applied to the Spread Spectrum Communication System

介绍了一种二维离散正交型Ｗａｌｓｈ 函数的构成与相关特性，将离散的Ｗａｌｓｈ函数进行平滑化之后，应用在广带域码分多址扩散频谱通讯中（ 简称ＣＤＭＡ 扩谱通讯） ．本文还发表了一种码分多址扩谱通讯的结构框图和通过各种复杂环境通讯实验结果．对比实验结果表明，平滑化的离散正交型Ｗａｌｓｈ 函数与非平滑化的离散正交型Ｗａｌｓｈ 函数作为在扩谱码，信号频带宽度之比为１：２， 用Ｗａｌｓｈ 函数（ 哈德码序列） 的正交码，目的是各种信道之间的相互干扰达到最小化．平滑化技术在同等的条件下，信噪比提高了２０ ｄＢ以上．说明这是一种非常成功的理论方法．

In this paper, we introduced the structure and correlative property of discrete Walsh function. After transform discrete Walsh function into smoothing Walsh function, that is applied to the spread spectrum communication system that name differential code CDMA (diffCDMA). We also proposed block diagram of diffCDMA and proposed computer simulation results through the multi ray propagation environment. The result is shown that the frequency bandwidth of the smoothing Walsh sequence code is equal to a half of frequency bandwidth of the no smoothing Walsh sequence code. The smoothing and orthogonal Walsh function sequence code act as spread spectrum code, our aim is to reduce the multi ray fading 20 dB under same experiment condition. The commuter simulations are verified for smoothing Walsh function to be successful method in the spread spectrum communication system.