Dissertation > Industrial Technology > Radio electronics, telecommunications technology > Communicate > Data communication > Data transmission technology

Research on the Synchronization and Equalization Technologies in OFDM System

Author WuZuo
Tutor ZhaoMinJian
School Zhejiang University
Course Information and Communication Engineering
Keywords Orthogonal Frequency Division Multiplexing (OFDM) Frequency offset estimation Maximum likelihood estimation (MLE) Equalization technology MIMO-OFDM Space-Time Block Code(STBC)
CLC TN919.3
Type Master's thesis
Year 2011
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Wireless mobile communication has experienced tremendous changes in recent ten years. The GSM network has brought great convenience to people’s life. Now the third generation communication, named 3G, has been successfully used in some country for commercial use, and our country also started to apply service of 3G just before several years. Now, people has changed their interests to the next generation communication system——the 4G.The 4G is supposed to apply higher data transmission speed than 3G, and it’s also supposed to be more efficient in spectrum and stronger to the interference in the signal. The Orthogonal Frequency Division Multiplexing (OFDM) is just such a technology:It’s a Multi-carrier system with each carrier a narrow band, the channel of a narrow band signal will be flat, so it’s strong to interference caused by wireless channels; Each carrier has 50% overlap to the adjacent carrier, so it’s efficient. That’s the reason that OFDM became an important technology in the physical layer of 4G.In this paper, the synchronization and equalization method is discussed, the construction of the paper is:In first chapter, the OFDM technology is introduced. This chapter also describes the advantages and disadvantages of this technology.In second chapter, in order to establish a basis for theory analysis, the channel model is introduced and the signal in wireless channel is analyzed.In third chapter the timing and frequency offset estimation method is discussed. The construction of train word, and the methods based on these construction are analyzed. The important point of this chapter is the analysis of the Maximum Likelihood Estimation (MLE) method. In this chapter the principle for designing an estimator using MLE and the error of this type’s estimator is studied, finally a new estimator is proposed is this chapter.In fourth chapter, the different equalization methods are discussed, the performance of these methods is also studied, based on these studies there’re some conclusions proposed in this chapter. Using these conclusions, a practical frame construction is proposed. It is shown this construction has both efficiency and high performance in design circumstance.In fifth chapter, the conclusions of the former chapters are used. By using these conclusions, the normal methods for MIMO-OFDM system are introduced. At the last of this chapter, a new

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