The Research Of Channel Estimation Technology In OFDM System And Design Of Its Basebands

In this paper, The fundament, the system architecture and the application of Orthogonal Frequency Division Multiplexing(OFDM) were discussed firstly. Secondly the mathematic model of Additive White Gaussian Noise and Time-varying Multi-path based on the discussion of mobile fading channel characteristic were analysed,and the channel model were implemented by computer simulation.Furthermore, the channel estimation techniques based on pilot for OFDM systems through different algorithms and improved algorithms for channel response estimation at frequency domain and time domain are inverstigated.And then this paper studies the channel estimation method for OFDM system based on transform-domain processing and the related filtering processing method. An improved channel estimation algorithm is presented for broadband OFDM system based on the tracking of power of the transform-domain single. Simultaneously the design of transform-domain filter is optimized by employing a new efficient lowpass filter and the filter's parameter is adjusted according to the power of the transform-domain single. And the lowpass filtering reduces AWGN and ICI significantly. It is demonstrated that tracking of power of the transform-domain single can improve the channel estimation performance and confirm good MSE and BER performance of the algorithm.The last design is to implement baseband data processing section on FPGA of an OFDM-based communication system, and it do works by timing analysis.