Design And Research Of Synchronization And Channel Estimation In Multi-Carrier Digital Television Broadcasting

Integrating with the modern communication technology, the digital television will take the place of the analog television across-the-board and become an important part of the information industry. There are four main standards of terrestrial broadcasting of digital television: DVB-T (Europe), ATSC (U. S. A.), ISDBT (Japan) and Chinese Digital Television Terrestrial Transmission Standard.Taking the DVB-T and the multi-carrier option of Chinese Digital Television Terrestrial Transmission Standard as research objects, the author analyzed and studied the synchronization and channel estimation technology of the OFDM system, and proposed several optimum algorithms and realization structures, most of which have been verified on the FPGA or ASIC.Main contents of this paper are as follows:The first chapter introduces the theory of OFDM firstly. Then it presents the transmission standards in digital television broadcasting which utilizes the OFDM technology. Finally it provides the structure and main contribution of the paper.Taking the DVB-T and DVB-H as research object, the second chapter introduces the base band transmission model of CP-OFDM. Then it discusses the techniques of the symbol synchronization, carrier recovery and timing recovery. An effective algorithm of symbol synchronization is presented which uses the time and frequency domain information in the OFDM system. It keeps synchronization well in single frequency network (SFN) where the multi-path delays may be longer than the guard interval. It also can track the variation of the symbol position fast.Taking the DVB-T and DVB-H as research object, the third chapter introduces the interpolation algorithms of channel estimation firstly. Then it presents a quasi-adaptive interpolation algorithm of channel estimation which chooses the optimal interpolation coefficient according to the practical channel parameters. Simulation results are provided to evaluate each interpolation algorithm. Secondly, it analyzes the inter-carrier interference (ICI) of the Doppler and provided an ICI equalization structures which have low hardware complexity and prominent performance. At last, the affection of phase noise is analyzed and three common phase error compensation methods were introduced.Taking the multi-carrier option of Chinese Digital Television Terrestrial Transmission Standard as research object, the fourth chapter introduces the base band transmission model of TDS-OFDM and basis theory of channel estimation and equalization of the TDS-OFDM system. Then it presents a frame synchronization and phase detection algorithm which works well in the severe multi-path channel with the high timing frequency offset. The chapter also discusses the affection of carrier frequency offset during the frame synchronization stage, and points that we can use the frequency scan to estimate the coarse carrier frequency offset. It discusses the timing and carrier recovery algorithms base on PN sequence and analyzed the performance and characteristic in the multi-path or mobile channel. Base on the output of correlation, a fine carrier offset estimation algorithm is provided. Finally, this chapter presents the detailed timing and carrier recovery schemes according to various channel models.It is the summary and expectation in the end of the paper.