US 7,139,320 B1Granted

Method and apparatus for multicarrier channel estimation and synchronization using pilot sequences

AssigneeTexas Instruments Incorporated

InventorsManoneet Singh, Arvind Lonkar, Jerry Krinock

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Abstract

Method and apparatus for OFDM synchronization and channel estimation. In a temporal embodiment, received embedded system pilot symbols are inverse Fourier transformed at expected index locations and correlated with computed complex conjugates of inverse Fourier transforms of pilot symbols for providing a correlation function for the channel impulse response. In a frequency domain embodiment, embedded system pilot symbols are augmented with pilot-spaced inferred guard band symbols, multiplied by scaled complex conjugates of computed pilot systems, and inverse Fourier transformed into the channel impulse response. Time and frequency are synchronized in feedback loops from information in the channel impulse response. The channel impulse response is filtered, interpolated, and then Fourier transformed for determining channel estimates for equalization.

Claims22

Dependent claims

A multicarrier signal receiver for receiving a serial signal sequence of modulated subcarriers carrying information for input pilot and data symbols, comprising:

a subcarrier-to-symbol converter for converting said serial signal sequence into received pilot and data symbols representative of said input pilot and data symbols;
an inverse Fourier transformer for selecting said received pilot symbols from said received pilot and data symbols and then inverse Fourier transforming said received pilot symbols into received pilot multicarrier blocks
a pilot multicarrier generator for generating a computed pilot multicarrier block having complex conjugates of system pilot symbols corresponding to said input pilot symbols;
a correlator for correlating said received pilot multicarrier blocks with said computed pilot multicarrier block for providing a correlation function;
a frequency offset estimator using said correlation function for providing a frequency synchronization adjustment;
and
a signal source for providing a reference signal having a frequency responsive to said frequency synchronization adjustment;
wherein:
the subcarrier-to-symbol converter uses said reference signal for frequency synchronizing to said serial signal sequence and providing a frequency synchronized serial signal sequence, said received pilot and data symbols derived from said frequency synchronized serial signal sequence.

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Dependencies are inferred from the claim text.