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Frequency Offset Estimation for MB-OFDM-Based UWB Systems in Time-Variant Channels

We address low-complexity, highly-accurate frequency offset estimation for MB-OFDM-based UWB systems in time-variant channels. We present a simple channel model capturing an abrupt channel change characteristic of UWB systems. We devise an abrupt channel change detector and develop an oscillator frequency offset estimator based on best linear unbiased estimation principle while taking into account the time-variant channel behavior as well as the MB-OFDM characteristics such as different carrier frequency offsets, different channel responses, different channel energies, and different preamble structures in different frequency bands. If compared to the conventional estimators using correlation, our proposed method achieves significantly better estimation performance for all preamble patterns of the MB-OFDM system.