现代移动通信中的调制技术研究(10)

参考文献

[1] 樊昌信等. 通信原理（第6版）[M]. 北京：国防工业出版社，2001:73-212 [2] 王沫然.Simulink4建模及动态仿真[M]. 北京：电子工业出版社，2002:47-78 [3] 吴伟玲等著.移动通信原理[M].北京：电子工业出版社，2005

[4] 娄莉. GMSK数字调制的仿真与分析[J]. 现代电子技术. 2004年第18期总第185期 [5] 曹志刚，钱亚生. 现代通信原理[M]. 北京：清华大学出版社，2001:49-81 [6] 约翰.G..普罗克斯，马苏德，萨勒赫著，刘树棠译. 现在通信系统——使用MATLAB

西安：西安交通大学出版社，2001:62-90

[7] 戴虹，戴悟僧. MATLAB在通信原理仿真中的应用[J]. 上海第二工业大学学报. 2001年，

第1期

[8] 綦朝辉，刘肖强，邓宪法.现代移动通信技术[M].北京：国防工业出版社，2006:128-166 [9] 李蕾，杜岩. 基于MATLAB的数字基带传输系统仿真实验设计[J]. 山东工业大学学报.

2001年2月第31卷第1期

[10] D.Hanselman,B.Littilefield著，张航等译. 精通MATLAB6. 北京：清华大学出版社，2002：99-137

[11] Rodger E.Ziemer and Carl R.Ryan．Minimum-shift keyed modem implementations for

high data rates．IEEE Communications Magazine, VT-21(4)28-37, October 1983． [12] Kazuaki Murota and Kenkichi Hirade GMSK modulation fordigital mobile radio

telephony IEEE Transactions On Communications, VT-29(7)345-355, July 1981．

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致 谢

本人在分析数字调制仿真系统及撰写论文期间，得到了很多老师和同学的帮助，在这里我首先要感谢的是我的指导老师李勇老师。在毕业设计的整个过程中，李勇老师在理论知识、工作任务、工作方向等方面给了我大量的指导和帮助，使我的毕业设计能顺利进行，并按时完成毕业论文。同时，我还要感谢大学三年里帮助我的各位老师，从他们身上，我不仅学到了理论知识，还学到了一丝不苟的学习态度。

另外，在毕业论文写作的过程中，我的朋友和我一起解决了很多遇到的难题，还有通信专业的其他同学也在各方面给了我很大的帮助，在这里，我对他们表示衷心的感谢，祝愿他们前程似锦，梦想成真！

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附录

附录[1] 外文文献

Simulink-based Simulation of Quadrature Amplitude

Modulation (QAM) System

Indiana State University Xiaolong Li

Abstract

Adaptive modulation system is one of the key techniques in building a broadband mobilecommunication network because of increasing shortage of wireless communication channels. Quadrature amplitude modulation (QAM) has been widely used in adaptive modulation because of its efficiency in power and bandwidth. To better understand the QAM system, a Simulink-based simulation system is designed. In the paper, the theory of M-ary QAM and the details of the simulation model are provided. In the simulation model, the parameter settings for random generator, QAM modulation and demodulation, AWGN wireless channel are provided. Error rates of QAM system versus the signal-to-noise ratio (SNR) are used to evaluate the QAM system for adaptive modulation. The model can be used not only for the criteria for adaptive modulation but also for a platform to design other modulation systems. Introduction

With the fast development of modern communication techniques, the demand for reliable high date rate transmission is increased significantly, which stimulate much interest in modulation techniques. Different modulation techniques allow you to send different bits per symbol and thus achieve different throughputs or efficiencies. QAM is one of widely used modulation techniques because of its efficiency in power and bandwidth. In QAM system, two amplitude-modulated (AM) signals are combined into a single channel, thereby doubling the effective bandwidth. However, it must also be noted that when using a modulation technique such as 64-QAM, better signal-to-noise ratios (SNRs) are needed to overcome any interference and maintain a certain bit error ratio (BER).

The use of adaptive modulation can increase the transmission rate considerable by matching modulation schemes to time varying channel conditions, which justifies its popularity for future high-rate wireless applications. Crucial to adaptive modulation is the requirement of channel state information at the transmitter. In figure 1, a general estimate of the channel state information for different modulation techniques is provided. As you increase your range, you step down to lower modulations (in other words, QPSK), but as you are closer you can utilize higher order modulations like QAM for increased throughput. In addition, adaptive modulation allows the system to overcome fading and other interference.

Both QAM and QPSK are modulation techniques used in IEEE 802.11 (Wi-Fi), IEEE 802.16(WiMAX), and 3G (WCDMA/HSDPA) wireless technologies. The modulated signals are then demodulated at the receiver where the original digital message can be recovered. The use of adaptive modulation allows wireless technologies to optimize throughput, yielding higher throughputs while also covering long distances.

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Figure 1: Adaptive Modulation and Coding [1]

To better understand the QAM system, a MATLAB/Simulink-based simulation system is designed in this paper. In the simulation model, the parameter settings for random generator, QAM modulation and demodulation, AWGN wireless channel are provided. Error rates of QAM systems versus the SNR are used to evaluate the QAM system for adaptive modulation. The model can be used not only for the criteria of adaptive modulation but also for a platform to simulate other modulation techniques. M-ary QAM

Modern modulation techniques exploit the fact that digital baseband data may be sent by varying both envelope and phase/frequency of a carrier wave. Because the envelope and phase offer two degrees of freedom, such modulation techniques map baseband data into four or more possible carrier signals. Such modulation techniques are called M-ary modulation, since they can represent more signals than if just the amplitude or phase were varied alone.

In an M-ary signaling scheme, two or more bits are grouped together t …… 此处隐藏：5985字，全部文档内容请下载后查看。喜欢就下载吧 ……