CHANNEL ESTIMATOR WITH HIGH NOISE SUPPRESSION AND LOW INTERPOLATION ERROR FOR OFDM SYSTEMS

摘要

A receiver with DFT based channel estimation having good noise suppression for both high and low signal-to-noise ratios providing advantages over conventional DFT estimators and Minimum-Mean-Square-Error (MMSE) estimators. The use of MMSE may be incorporated for estimation at the band edges providing further improvements. The received signal in the time domain, is transformed to the frequency-domain received signal via an N-point FFT (501). The frequency-domain received signal at the pilot locations is then used to obtain a “noisy” channel estimates at the pilot subcarriers by dividing the known pilot symbols in (503). Uniformly spaced pilots are assumed over a window of usable subcarriers. Padding is applied to the initial channel estimates at both sides of the band to account for unused subcarriers such as guard spacing. Weighting factors during power estimation may take into account various noise characteristics such as combinations of known and time-limited noise power characteristics.