Decision Feedback Channel Estimation Algorithm Guided by Training Sequence
|Course||Signal and Information Processing|
|Keywords||Orthogonal frequency division multiplexing (OFDM) Channel estimation Pilot Decision Feedback|
Focus on the future wireless mobile communication system, you really want to achieve high-speed, high-quality, real-time tracking to achieve seamless coverage effect, it must be the introduction of new technologies, new means. Along with the rapid development of wireless communication technology, spectrum resources appearing increasingly tense, how to save and rational use of existing spectrum resources has become an urgent problem to be solved, so people will refocus on orthogonal frequency division multiplexing (OFDM, Orthogonal Frequency Division Multiplexing) technology, the body, the reason is very simple, because of its high spectral efficiency and has a strong anti-multipath capability. By examining the OFDM channel estimation is because only timely access to the channel state information to the channel for real-time and accurate coherent demodulation. In this thesis, is the OFDM channel estimation techniques for a deep study and presents a guided training sequence based decision feedback channel estimation algorithm for channel estimation. Firstly, the paper briefly describes the OFDM technology research background, significance and development and research status quo. Secondly, the paper analyzes the characteristics of several radio channels, behind the need for OFDM channel estimation to establish the appropriate channel model and analyzed in detail. Again, the paper describes the basic principles of OFDM system for OFDM system to analyze the advantages and disadvantages, not only for the OFDM key technology in detail, and mainly discussed the key technologies in OFDM system channel estimation techniques, and three kinds of channel estimation method that is based on pilot symbols and interpolation techniques estimation methods, blind channel estimation algorithm, semi-blind channel estimation method for a more detailed analysis. Finally, the study of OFDM channel estimation techniques, focusing on the time-varying channel based on pilot and decision feedback channel estimation. Which describes the least-squares (LS, Least square) algorithm and the minimum mean square error (MMSE, Minimum Mean Sequare Error) algorithm and its improved algorithm and various interpolation algorithm. Since the channel time variation will cause the system subcarriers orthogonal been destroyed, this will inevitably produce the inter-channel interference (ICI), then, papers with training sequence based guided decision feedback channel estimation algorithms for channel estimation, and presented on the basis of the instantaneous values ??of the channel estimation algorithm of the sliding average to optimize the original decision feedback algorithms. Simulation results show that: in the time-varying channel conditions, the use of improved decision feedback channel estimation algorithm than the original algorithm reduces the error rate and minimum mean square error.