WCDMA下行链路扩频调制的仿真与浅析.doc

WCDMA下行链路 扩频调制的仿真与浅析 目 录 摘 要： 1 0 前言 2 1 概述 2 1.1 3G概述 2 1.2 WCDMA简介 3 1.3 WCDMA系统模型 3 1.4 WCDMA的发展 4 2 WCDMA扩频 5 2.1 扩频简介 5 2.2 扩频编码 6 2.3下行链路扩频过程 9 3 WCDMA调制 10 3.1调制简介 10 3.2 QPSK数字调制 11 3.3 下行链路调制过程 11 4 WCDMA下行链路扩频调制的仿真 12 4.1 仿真模型 12 4.2 仿真结果及分析 14 5 结论 18 参考文献 19 WCDMA下行链路扩频调制的仿真与浅析 摘 要： 移动通信系统已经历了第一代模拟通信系统和第二代数字通信系统（GSM、CDMA），目前正朝第三代移动通信系统发展。WCDMA作为未来的主流技术，已经得到业界的广泛认可。WCDMA是基于GSM网发展出来的3G技术规范，是欧洲提出的宽带CDMA技术。它具有较高的扩频增益，发展空间较大，全球漫游能力最强，技术成熟性最佳。本文首先简单介绍了第三代移动通信系统WCDMA扩频调制的基本原理以及操作过程,然后利用MATLAB工具建立了WCDMA的下行链路扩频调制过程的仿真模型,最后给出了各个处理阶段信号的频谱图等仿真结果,并进行了分析,得出利用 OVSF 扩频码进行扩频调制能够很好地解决不同业务传送及多用户干扰的问题。 关键词： WCDMA;扩频；调制；MATLAB仿真 Study and Simulation of WCDMA Downlink Channel’s Spreading and Modulation Abstract: Mobile communication system has experienced a first-generation analog communications system and the second generation of digital communication system (GSM, CDMA), is currently facing the third generation mobile communication system development. WCDMA as my future mainstream technologies has been widely recognized in the industry. WCDMA is developed based on GSM network 3G technology standard, is the European proposed broadband CDMA technology. It has higher spread spectrum gain; development space bigger, global roaming ability to recognize the strongest, technology is the best. This paper firstly illustrates the theory and operational process of WCDMA Downlink channels spread spectrum and modulation briefly. Secondly the simulation module of WCDMA uplink channel is founded by MATLAB, and then the result of the simulation is given. Based on the preceding study and simulation the conclusions that the OVSF which is used in WCDMA can primal solve the problems of the different operation ‘transmission and the different users disturbance are educed at last. Key words: WCDMA;spreading;modulation; MATLAB simulation 0 前言 自从电话进入人类社会以来，人们对它的依赖与日剧增，这主要是由于电话使用方便快捷，可以节约大量的时间。随着人们对移动通信的全新探索，第三代移动通讯的迅速兴起，大大方便人们的生活生产，并给生活带来全新享受 Wideband CDMA的下行链路扩频与调制,以及