Frequency offset estimation for MB-OFDM-based UWB systems

We address low-complexity, highly-accurate frequency offset estimation for multi-band orthogonal frequency division multiplexing (MB-OFDM) based ultra-wide band systems in time-invariant as well as time-variant channels. We investigate the unique characteristics of MB-OFDM systems, namely, different frequency offsets, channel responses, received energies, and preamble structures in different frequency bands. Utilizing them, we develop frequency offset estimators based on the best linear unbiased estimation principle. If compared to the reference estimators, our proposed methods achieve significantly better estimation performance (4 to 6.4 dB (5 to 20 dB) estimation mean-square error advantage in the time-invariant (time-variant) channels) for all preamble patterns of the MB-OFDM system in [8].