Patent ID: 8837651

Claim:
A receiving apparatus of a wireless access system, the apparatus comprising: a pilot symbol extractor for extracting pilot symbols from a data being received from a processor; a channel correlativity estimator for measuring channel correlativity with respect to a time axis and a frequency axis using the extracted pilot symbols; a first channel estimation filter having a tap coefficient which is channel-adaptively variable, the first channel estimation filter acquiring a channel impulse response by filtering received pilot symbols; a second channel estimation filter having at least a filter with a fixed tap coefficient, the second channel estimation filter acquiring a channel impulse response by filtering received pilot symbols; and a selector which selects one of the first channel estimation filter and the second channel estimation by comparing the channel correlativity with a threshold; wherein the second channel estimation filter is not operating if the first channel estimation filter is selected, and the first channel estimation filter is not operating if the second channel estimation filter is selected, wherein the first channel estimation filter is different from the second estimation filter.