Patent ID: 7936848
Filing Date: 2011-05-03
Classification: H04L

Abstract:
1. An apparatus for estimating a channel in a Broadband Wireless Access (BWA) communication system, comprising: a subcarrier demapper for extracting pilot symbols at preset positions for a channel estimation; a channel estimator for acquiring channel estimate values of subcarriers through an Infinite Impulse Response (IIR) filtering using the pilot symbols provided from the subcarrier demapper and a preset filter factor value based on changes in the channel condition; and a filter factor selector for selecting an optimal filter factor required for the IIR filtering per frame among a plurality of pre-classified filter factors using the pilot symbols provided from the subcarrier demapper, wherein the channel estimator performs the IIR filtering using the filter factor selected by the filter factor selector, instead of the preset filter factor, wherein the filter factor selector estimates a channel estimate value of a preamble, estimates a channel estimate value of a first symbol by applying the IIR filtering using symbols after the preamble with respect to each of the pre-classified filter factors, measures an error accumulation value which accumulates errors between the preamble and the estimated first symbol for each of the pre-classified filter factor, measures a moving average which averages the error accumulation values during a preset number of frames with respect to each of the pre-classified filter factors, and provides a filter factor of the smallest moving average among the measured moving averages to the channel estimator.