文档介绍：基于FPGA实现CDMA扩频通信中的同步系统
摘要
扩频通信是应用频谱展宽技术,实现加密、选址通信的一门新技术。扩频通信最早应用在军事方面,主要用于抗干扰和保密措施。随着移动通信的迅猛发展,基于扩频理论的CDMA技术已成为国际电联规定的第三代移动通信系统的主要标准化建议,从而确立了CDMA通信技术在移动通信的稳固地位,这标志着扩频通信技术在通信领域的应用进入了新阶段。它不仅在军事通信方面发挥着不可取代的优势,而且广泛地渗透到了民用通信的各个方面,如卫星通信、移动通信、微波通信、无线电定位系统、无线局域网、全球个人通信等。
本文的目标是实现一个CDMA扩频通信同步实验系统,给用户提供一个良好的学台。本文主要从以下几个方面论述系统的设计与实现:首先概述了扩频通信技术的基本原理和当前在实际中的应用,接着简要阐述了CPLD器件的相关知识以及硬件描述语言Verilog HDL和Quartus ;然后提出实验系统发送端的设计方案,Gold码发生模块和合路相加模块。重点研究了伪随机码所需具备的特性,概述了两种常用的伪随机码m序列和Gold序列,讨论了其产生原理以及相关特性等,并用Verilog语言在CPLD上实现了Gold码;紧接着提出实验系统接收端的设计方案,包括积分器模块、分频器模块和比较器模块,完成发送端和接收端Gold码的同步。即伪码捕获。并详细论述了本系统采用的滑动相关检测技术实现伪码精确同步的方案。
最后,对整个系统进行调试仿真,从模块波形图可以看到,该系统实现了接收端Gold码的同步捕获,所采用的伪码同步方案也能获得良好的性能。
关键词:Gold码;捕获;CDMA同步
Achieve synchronous CDMA spread munication system Based on FPGA
ABSTRACT
Application of spread munication is broadening spectrum technology, encryption, and site of a munications technology. Spread munications in the military aspects of the earliest applications, mainly for anti-jamming and security measures. With the rapid development of munication, the theory based on spread spectrum CDMA technology has e the third generation of ITU regulations major munication system standardized mendations, which established the CDMA munication technology in strong position, which marked the spread munication technology in the field munications applications to enter a new stage. Not only does it play in the munications irreplaceable advantages, but also extensively rated into all aspects of munications, such as munications, munications, munications, radio positioning system, wireless LAN, global munications.
This goal is to achieve a synchronous CDMA spread munication experimental system, to provide a good learning platform for spread munication technology experiments. This article discusses the following aspects from the design and implementation of the system: First, an overview of the basic principles of spread munication technology and the current application in