Abstract
In this thesis, we exploit the flexibility OFDM provides to improve the performance of channel estimation. Channel gain, which can be obtained by channel estimation, is significant information for coherent demodulation and dynamic resource allocation. It can be assumed that the better the channel estimation, the better the system performance. As for MB-OFDM systems, due to the TFC that governs the selection of available band, interference becomes an unavoidable problem. Compared with thermal noise, the damage interference may cause are much more severe. As a result, we focus on eliminating interference throughout this thesis. The most important property been exploited is the time domain redundancy. With the property, we propose a series of TR estimators. Although interpolation is needed for TR estimators, we can still benefit from the elimination of interference and the enhancement of SNR at the sub-carriers with pilots symbol on it. In addition, with the time domain diversity, we can apply several diversity combining schemes on the received symbol. However, due to the inevitable interpolation and the resulting interpolation error, there exists certain trade-off. We have some numerical derivation to help decide which estimator to use and make some simulation to verify the numerical results. With the simulation and numerical results, we can expect the improvement by using TR estimators. Finally, besides MB-OFDM UWB system, we anticipate better performance in other OFDM systems adopting the TR estimator.