WH-m/M相乘复合码扩频系统的互扰统计特性

本文建立了复合码ＤＳ－ＣＤＭＡ扩频系统的数学模型，推导了多址干扰的数学表示，定义了用户之间的互扰因子，并进行了计算，研究发现，在扩频比相同的上，若ＰＮ序列周期大小扩频比，且序列的伪随机性产好，则采用ＷＨ－ｍ／Ｍ复合序列与采用ｍ－Ｍ序列的扩频系统，其互扰因子均呈高斯分布，且数字特征相同，当ＰＮ序列周期等于扩频比时，互扰因子不具有高斯分布特性，该结论不要求扩频比足够大，而且对同步和异步ＤＳ－ＣＤＭＡ通

On the Statistical Properties of the Cross-Interference in the DS-CDMA System Using the WH-m/M Concatenated Sequences

In this paper,the mathematical expression of the MAI as well as the definition of the crossinterference k,i between two users are developed.The results from the computer calculation show that:when the length of a PN code P with good pseudorandomness is greater than the spreading ratio N,no matter whether using the WHm/M concatenated sequences good pseudorandomness isgreater than the spreading ration N,no mather whether using the WHm/M concatenated sequencesor the m (or M) sequence as the spreading sequences,their crossinterference are all accordant with Gaussian distributions with equal moments characteristics;and when P is equal to N,k,i is not accordant with Gaussian distribution.This conclusion leads to no need for large spreading ratio and is applied to both synchronous and asynchronous DSCDMA systems.