| Summary: | 碩士 === 國立臺北科技大學 === 電腦與通訊研究所 === 99 === The digital multimedia broadcasting-terrestrial(DMB-T)adopts the time domain synchronization-orthogonal frequency division multiplexing(TDS-OFDM).Instead of cyclic prefix scheme in traditional CP-OFDM systems, PN sequence has been proposed for guard interval, system synchronization and channel estimation in DMB-T system. TDS-OFDM provides higher spectrum efficiency than CP-OFDM due to no pilot in the transmitted signal.
In this paper, windowing and signal reconstruction are introduced to subtract the PN sequence padding for the TDS-OFDM systems to mitigate the residual inter symbol interference (ISI) from the imperfect channel estimation. Two kinds of channel models, TU6 and COST 207, there are short time delay and long time delay respectively to verify and evaluate channel estimation algorithm and equalizer. In this thesis, using Matlab simulated DMB-T transceiver and two kinds of channel estimation algorithm, one is convention channel estimation algorithm and the other is proposed channel estimation algorithm, two kinds of channel estimation algorithm are used to verify and estimate the performance of channel estimation algorithm.
Results show that this algorithm can effectively remove the impact from the residual ISI on the slow-fading and fast-fading TU6 channels, even in the presence of large channel delays in the COST 207 channel.
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