扩频通信系统的MATLAB仿真

扩频通信系统的MATLAB仿真

摘要

扩频通信，即扩展频谱通信( Spread Spectrum Communication)，它与光纤通信、卫星通信，一同被誉为进入信息时代的三大高技术通信传输方式。本文详细阐述了扩展频谱通信的理论基础和实现方法，并通过Matlab对直扩通信系统进行了仿真，并对各基本模块进行设计和仿真。此外，在给定仿真条件下，运行了仿真程序，得到了预期的仿真结果。同时，利用建立的仿真系统，通过对比一般通信系统和基本扩频通信系统的仿真，研究了扩频通信系统抑制信道干扰和码间干扰的性能，结果表明，扩频通信系统确实能很好的提高通信系统的可靠性。

关键词：直扩通信；Matlab；Simulink；仿真

Spread spectrum communication system simulation with

MATLAB

Abstract

. Spread spectrum communication, namely the spread spectrum communication (Spread Spectrum Communication), optical fiber communication and satellite communication is together known as the three high-tech communication transmission mode in the information age. This paper expounds the theoretical foundation and realization method of the spread spectrum communication. By the Matlab simulation platform, spread spectrum communication system is simulated, and each basic is designed and simulated as well. In addition, in a given simulation conditions, running the simulation program obtained the expected simulation results. At the same time, using the simulation system, by comparing the general communication system and the basic spread spectrum communication system simulation, studied the spread spectrum communication system to suppress channel interference and inter-symbol interference performance. The results showed that the spread spectrum communication system does good to improve the reliability of communication system.

Key words: DSSS communication; Matlab ; Simulink ;Simulation

目录

摘要................................................................................................................... I Abstract ................................................................................................................ II 前言 (1)

1 绪论 (2)

1.1 选题的背景 (2)

1.2 选题的主要任务 (3)

2 扩频通信系统 (4)

2.1 扩频通信的定义 (4)

2.2 扩频通信的理论基础 (5)

2.3 扩频通信系统的工作原理 (7)

2.4 扩频通信的主要特点 (8)

2.5 扩频通信的主要性能指标 (10)

2.5.1 处理增益 (10)

2.5.2 抗干扰容限 (11)

3 直接序列扩频通信的性能分析 (12)

3.1 直接序列扩频通信系统概述 (12)

3.2 直接序列扩频通信系统的数学模型 (13)

3.3 多径干扰 (14)

3.3.1 多径干扰的概念 (14)

3.3.2直扩系统的抗干扰性 (15)

3.3.3直扩系统的抗截获性 (16)

3.3.4直扩码分多址通信系统 (17)

3.3.5 直扩系统的抗多径能力 (17)

3.4 直接序列扩频通信系统的伪随机码的选择 (18)

3.4.1 扩频码简介 (19)

3.4.2 m序列 (19)

4 直接序列扩频通信系统的仿真基础 (25)

4.1 Matlab语言与仿真环境介绍 (25)

4.1.1 Matlab仿真环境简述 (25)

4.1.2 Matlab语言介绍 (26)

4.2 基于matlab通信仿真的基本步骤 (27)

4.3 Simulink建模仿真的一般过程 (27)

4.3.1 Simulink建模仿真的基本步骤 (27)

4.3.2 Simulink中功能模块的连接及设置 (28)

5 直接序列扩频通信系统的仿真 (32)

5.1 Simulink的仿真 (32)

5.1.1 扩频与解扩的Simulink仿真 (32)

5.1.2 BPSK调制的Simulink仿真 (34)

5.1.3 编码信道的Simulink仿真 (36)

5.2 Matlab源程序设计 (38)

总结 (48)

致谢 (49)

参考文献 (50)