| Summary: | 碩士 === 輔仁大學 === 電子工程學系 === 98 === A semiblind method of joint channel and carrier frequency offset estimation is proposed for single-input multiple-output (SIMO) zero-padded orthogonal frequency-division multiplexing (ZP-OFDM) systems. By stacking all the received OFDM symbols, the stacked channel matrix is of block Toeplitz. The block matrix scheme is then presented such that a group of subvectors are formed from the stacked OFDM signal and the number of equivalent samples is increased. With the extra samples, the perturbations of sample correlation matrix and the noise subspace are reduced, and therefore, the channel estimation error is lowered. The novel channel estimator can also work very well even with only a few OFDM symbols. Based on the novel channel estimator, a pilot OFDM symbol is then exploited to resolve the carrier frequency offset (CFO) and the ambiguity factor. An iterative algorithm is developed for the CFO estimation. Computer simulations demonstrate that the proposed joint channel and CFO estimation is effective and robust compared with existing methods.
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