Channel Estimation For MB-OFDM UWB System

Multiband Orthogonal Frequency-division Multiplexing(MB-OFDM)-based Ultra-Wideband(UWB) communication technology has recently been applied in Wireless Personal Area Network(WPAN), primarily due to its high data rate transmission capability with high bandwidth efficiency and robustness to multi-path fading effects at a relatively low cost and deep penetration capability. Coherent demodulation has been adopted to accurate channel information in receiver to implement channel estimation and equalization.This dissertation is concerned with the estimation of channel to adaptive MB-OFDM UWB systems in complex multipath indoor environments. In the first part, we study the temporal and spectral properties of UWB,and its performance in UWB multipath channel environment and some common channel models for UWB indoor propagation.we then analyze the standard channel model developed by IEEE802.15.3a Group. Some simulation figures was also derived from the model parameters to verify the characterizes of multipath propagation. We also describe the architecture for a MB-OFDM UWB system. It's consist of source coding, information coding, OFDM signals implementing which adaptive transmission in UWB system, and etc function blocks as the theoretical basis for later investigation.Then we get many investigation on channel estimation methods for MB-OFDM UWB, including Least Square(LS) algorithm, Minimum Mean Square Error(MMSE)algorithm and its based Discrete Fourier Transform(DFT) improved algorithm. Then we simulate the Bit Error Rate(BER) and Mean-square Error (MSE) performance and compare computational complexity of these methods in UWB channels are analyzed.we got the BER performance and the computational complexity are contrary. We discuss these method could been applied in particular environment.In the last, a using improved channel estimation technique is proposed for MB-OFDM UWB system which using kalman filter to modify the channel frequency estimation from LS algorithm. There is a decision feedback segment in receiver to enhance former estimation.The proposed method is compared with other existing channel estimation methods at BER performance.