ABSTRACT
Commonly digital modulation schemes are amplitude shift keying, phase shift keying, differential phase shift keying, frequency shift keying and quadrature amplitude modulation (QAM). Each modulation technique has its advantages and disadvantages in a certain working environment. QAM is widely used in wired and wireless communication due to its high bandwidth efficiency. In general, the error performance of QAM is obtained via Monte Carlo simulation, especially when analytical analysis is difficulty. A large number of random data and additive white Gaussian noise (AWGN) samples need to be generated. Iterations are often used as a programming habit of languages like C or Fortran. MATLAB however, is a matrix based programming language. It is more efficient in matrix computation than iterations. Therefore, the conventional programming using iterations results in long execution time. Simulation efficiency is greatly improved, when iterations are replaced by matrix computation.
This thesis starts with a general introduction of the research topic in chapter 1. Chapter 2 gives an introduction of QAM and its error performance analysis. In chapter 3, we look into general scenarios where execution time can be reduced by improvement in MATLAB programming. In chapter 4, a conventional 16QAM error performance simulation program is modified and improved. Comparisons show that the simulation time is greatly reduced. We also programmed a user-friendly Graphic User Interface (GUI) in MATLAB for easy execution and comparison. Conclusions are made in chapter 5.
Keywords: BER, Simulation efficiency, 16QAM, MATLAB
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目录
摘要 I
ABSTRACT II
第1章 引言 1
1.1 背景 1
1.2 研究内容 1
第2章 正交幅度调制(Quadrature Amplitude Modulation) 3
2.1 什么是QAM 3
2.2 QAM调制 3
2.3 QAM的解调与检测 4
2.4 QAM的误码率性能 5
2.5 正交幅度调整的优点与缺点 6
第3章 MATLAB下如何对QAM仿真进行效率优化 7
3.1 对仿真程序进行效率优化的必要性 7
3.1.1 M文件简介 7
3.1.2 循环向量化编程 7
3.2 如何优化仿真效率及其步骤 10
3.2.1 分析代码的运行状况 10
3.2.2 循环矩阵化 10
3.2.3 预先定义变量 11
3.2.4 内存的管理 12
3.2.5 其他方法介绍 12
3.3 难以采用矩阵算法的类型 13
第4章 利用MATLAB进行16QAM误码率仿真 14
4.1 矩形16QAM的误码率和误比特率仿真程序改造 14
4.2 程序效率比较 16
4.3 程序效率比较结果 17
4.4 MATLAB 图形用户界面编程 18
第5章 结束语 19
致谢 20
参考文献 21
附录 源代码 22