| 摘要 |
<p>In an OFDM system pilot signals are applied to different subcarriers of different symbols in accordance with a pilot transmission scheme. Channel impulse response (CIR) estimates are determined by time-interpolation for some of the data slots of the received signal which do not already include a pilot signal. For each of a sequence of symbols, a respective IFFT is performed on the pilot signals and interpolated channel estimates in the data slots of that symbol, thereby determining a sequence of estimated CIRs for the sequence of symbols. Spurious channel components will vary across the sequence of estimated CIRs, whereas the true channel peaks tend not to vary significantly (fig.9, not shown). Therefore the sequence of estimated CIRs is filtered (e.g. with a low-pass filter) to attenuate the spurious components. The filtered CIR is then used in positioning a sliding window to sample received symbols.</p> |
