扩频通信系统抗干扰分析

电子通信论文编号:TX166 附开题报告,任务书,及前期过程资料,论文字数:23423,页数:40 

目   录

1绪论………………………………………………………………………………1
2 扩频通信系统………………………………………………………………………2
2.1 扩频技术的历史 ………………………………………………………………………2
2.2 扩频通信系统的工作环境…………………………………………………………4
2.3 扩频通信的原理和理论基础………………………………………………………4
2.4 扩频的实现方式……………………………………………………………………5
2.5 扩频系统的信道使用 …………………………………………………………………6
2.6 扩频通信的特点 ………………………………………………………………………6
2.7 应用范围 ………………………………………………………………………………7
3 扩频通信系统的抗干扰技术 ……………………………………………………………………8
3.1扩频抗干扰技术 ………………………………………………………………………8
3.2 扩频码的作用…………………………………………………………………………14
3.3 信道编码………………………………………………………………………………16
3.4 空域、时域自适应滤波技术…………………………………………………………19
3.5 自适应天线技术………………………………………………………………………19
3.6 自适应功率控制技术…………………………………………………………………20
3.7 自适应干扰对消系统…………………………………………………………………20
4 一些新的抗干扰技术 …………………………………………………………………21
4.1二维扩频………………………………………………………………………………21
4.2多输入多输出技术…………………………………………………………………23
4.3超宽带脉冲无线电技术……………………………………………………………24
4.4自编码扩频…………………………………………………………………………25
5直接序列扩频通信系统仿真方案………………………………………………………27
5.1 Simulink简介 …………………………………………………………………………27
5.2实现方法………………………………………………………………………………30
结论 ………………………………………………………………………………………34
致谢 …………………………………………………………………………………35
参考文献………………………………………………………………………………36

摘 要

 随着人们生活质量的提高，无线用户的数量以惊人的速度迅速增长，到处充斥着各种频率的电磁波，导致本已恶劣的通信环境更加恶劣。所以通信系统的抗干扰性能越来越成为人们关注的焦点。扩频通信系统的抗干扰技术包括扩频抗干扰技术和非扩频抗干扰技术两大类，这两类技术在现行的扩频通信系统中都有着广泛的应用。在重点分析包括扩频抗干扰技术、智能天线技术、二维扩频、自编码扩频等在内的抗干扰技术的基础上，在Matlab仿真平台上完成了对直接序列扩频通信系统的仿真，模拟了直接序列扩频通信的实现过程。通过对仿真事件的结果分析，得出了在相同误码率下，增大扩频增益，可以提高系统输出端的信噪比，从而提高系统的抗干扰能力的结论。

关键词   扩频通信  扩频码  信道编码  二维扩频

Title        The Interference Analysis Of Spread Spectrum     

                    Communication System                

Abstract
As the quality of people’s life is improved, the number of wireless users growthed very rapidly，and everywhere awash with the frequency of the electromagnetic wave, this has led to the poor communications environment even worse. Therefore, the communication system’s anti-jamming performance has increasingly become the focus of people’s attention. The spread spectrum communication system’s anti-jamming technology including two kinds, spread spectrum anti-jamming technology and non-spread spectrum anti-jamming technology. The two kinds technology both have widely used in today’s spread spectrum communication system. On the base of laid special stress on analyse the anti-jamming technology including spread spectrum anti-jamming technology, smart antenna technology, two-dimensional spread spectrum, and coding itselfly spread spectrum，I accomplished a simulation plan of the direct sequence spread spectrum communication system through the Matlab, simulated the realize process of the direct sequence spread spectrum communication system successfully. Through the analysis of the result of the simulation event, I get the conclusion that on the base of the same error rate, if you increase the spread spectrum gain, you can increase the signal-to-noise ratio on the output port, thus increased the anti-jamming ability.

Key Words   Spread Spectrum Communications    Spreading Codes  
Channel Coding    Two-dimensional spread spectrum