mqam调制方式的频域均衡系统研究.doc

MQAM调制方式的频域均衡系统研究

摘  要

单载波频域均衡（SC/FDE）技术，不仅可以有效对抗信道的频率选择性衰落，实现高速率、大容量的通信传输，而且能够避免单载波时域均衡（SC/TDE）复杂度大和正交频分复用(OFDM)技术峰均功率比高的不足，是宽带无线接入系统物理层的重要组成技术。近五年来，关于单载波频域均衡的讨论日渐增多，并且已经被纳入IEEE802.16(WiMAX)标准中。然而对SC/FDE的研究大多还只是集中在理论仿真阶段，很少有实际的系统实现。
本文介绍了采用MQAM调制方式的单载波频域均衡(SC/FDE)技术。MQAM是一种节省频带资源的数字调制方式，广泛应用于有线数字视频广播和宽带接入等通信系统中， 本文重点研究频域均衡的基本思想、均衡器的结构、LS均衡算法和一种采用16QAM调制方式的SC/FDE系统的Matlab仿真调试。
关键词：单载波调制； 频域均衡； SC/FDE； MQAM； LS算法。
 
ABSTRACT

   SC/FDE (Single Carrier-Frequency Domain Equalization) allows an advantage of high-speed data transmission in frequency-selective fading channel. It avoids the complexity of SC/TDE (Single Carrier-Time Domain Equalization) and the high PAPR (Peak Average Power Ratio) of OFDM (Orthogonal Frequency Division Multiplexing) as well. It becomes one of the most important components of the wideband wireless access technique. In recent years, there is more and more discussion about SC/FDE, including been brought into the IEEE802.16 (WIMAX) protocol .However, most of research work still focuses on theories of parts not whole system ,and less implementation in real hardware platform .
This paper introduces the technology of SC/FDE with the modulation method of 16QAM. MQAM is a digital modulation which saves bandwidth resources. It is widely used in cable digital video broadcasting and broadband access and other communications systems. This paper focuses on the basic idea of frequency-domain equalization and the structure of equalizer. The LS equalization algorithm is also given, as well as the simulation and debugging of SC/FDE with 16QAM modulation on Matlab platform.
Keyword: Single-Carrier modulation; Frequency-Domain Equalization; SC/FDE; MQAM; LS algorithm .
目    录

第一章  绪  论 1
1.1单载波频域均衡 (SC/FDE) 系统概述 1
1.1.1正交频分复用(OFDM)系统 1
1.1.2 SC/FDE系统的概述 2
1.1.3 OFDM和SC/FDE系统的比较和共存 4
1.2 SC/FDE技术应用及前景 6
1.3 研究的目的及意义 6
第二章  MQAM调制与解调的相关理论 7
2.1 QAM调制与解调的原理 7
2.2 多电平QAM调制与解调原理 8
第三章  均衡原理 10
3.1 均衡的概念和意义 10
3.2 均衡的分类 10
3.2.1 时域均衡 10
3.2.2 频域均衡 12
3.3 频域均衡的基本思想和算法 13
3.3.1 频域均衡的基本思想 13
3.3.2 最小二乘算法 14
第四章  信道估计 15
4.1信道的分类 15
4.2 宽带无线移动信道 15
4.2.1无线信道分析 15
4.2.2平坦衰落信道 16
4.3 SC/FDE系统中的信道估计技术 17
第五章  SC/FDE系统的仿真 19
5.1 仿真MATLAB的介绍 19
5.1.1 MATLAB 19
5.1.2 MATLAB工具箱 19
5.2 计算机仿真 20
5.2.1 高斯信道中SC/FDE系统的仿真 20
5.2.2 运行结果分析 33
结束语 35
致谢 36
参考文献 37
附录 38