Research And Implementation Of Channel Estimation Algorithm Based On DTMB System

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.), ISDB-T(Japan) and Chinese Digital Television Terrestrial Transmission Standard(for short: DTMB).Channel estimation and equalization are one of the core problems in the design of receivers in DTMB. For the single carrier Digital Television Broadcasting-Terrestrial receiver, the method of direct adapt equalization can be used. For multi-carrier Digital Television Broadcasting-Terrestrial receiver, its common to use indirect equalization method which combines channel estimation and equalization have compact relationship. In this paper, the channel estimation and equalization in DTMB system are studied.This dissertation depends on the project of baseband decoded chip of DTMB DTV standard. Firstly the writer introduce its technical background and present terrestrial transmission system at home and abroad, illustrate the basic structure of DTMB, analyze the channel character of terrestrial transmission mode. And then the writer select three commonly used channel estimation algorithms which are basically suitable for DTMB frame structure from numerous algorithms, analyze their advantages and disadvantages and calculate their cost of implementation, afterward present an algorithm which is suitable for DTMB system and give details of the overall solution. In order to attain performance based on DTMB and improve algorithm capability, study three kinds of approach to improve the performance. Particularly aim at the contradictory problems of LMS algorithm convergence speed and estimation accuracy, there is an increase of the Doppler estimation module, using the estimated Doppler frequency is dynamically adjusted parameters, so that not only fast convergence algorithm, and improve estimate accuracy. Simulation results show that the algorithm reached at GB TOV basic requirements, furthermore it represent better performance on a variety type of channels. The Channel Estimation and Equalization project applies to all known sequences of time-domain OFDM system.What the writer has done is as follows: Summed up the three commonly used channel estimation program, to analyze its merits and complexity of implementation; Provide an algorithm based on LMS and a detailed implementation; For algorithm defects give three methods to improve, so that algorithm performance will not only meet the national standard requirements, and show excellence performance in a variety of channels.