OFDM channel estimation system and method components

摘要

Channel estimation for high mobility OFDM channels is achieved by identifying a set of channel path delays from an OFDM symbol stream including carrier data, inter-channel interference noise and channel noise; determining the average channel impulse response for the identified set of channel path delays in each symbol; generating a path delay curvature for each channel path delay in each symbol based on stored average channel impulse responses for the identified channel path delays; estimating the carrier data in the symbols in the OFDM symbol stream in the presence of inter-channel interference noise and channel noise from the OFDM symbol steam and the average impulse responses for the identified channel path delays; reconstructing the inter-channel interference noise in response to the path delay curvature, the identified set of channel path delays and estimated carrier data to produce a symbol stream of carrier data and channel noise with suppressed inter-channel interference noise.

主权项

1. A system comprising:
an average channel estimator circuit, responsive to an Orthogonal Frequency Division Multiplexing (OFDM) symbol stream and a set of channel path delays, comprising: an extraction circuit for extracting an OFDM symbol from the OFDM symbol stream; an input circuit for receiving a set of channel path delays corresponding to the OFDM symbol, each path delay corresponding to one of a plurality of transmission paths between a transmitter and a receiver; and an estimator circuit for estimating, for each of the plurality of transmission paths, an average path gain corresponding to each of the set of channel path delays based on least squares and known noise; a curve generator circuit communicatively coupled to the average channel estimator circuit, and responsive to stored average impulse responses, comprising:
a selection circuit for selecting, from storage, average channel gains of neighboring OFDM symbols;a rate determining circuit for determining a rate of change of the neighboring average channel gains; anda model selection circuit for identifying a best-fit average free curve for the stored channel impulse responses,wherein the model selection circuit selects an order of the best-fit average free curve based on the determined rate of change and wherein an average of the best-fit average free curve comprises an average channel response; and a carrier data estimator circuit communicatively coupled to the average channel estimator circuit, responsive to the OFDM symbol stream and average impulse responses from the average channel estimator circuit, for estimating the carrier data in the symbols in the OFDM symbol stream in the presence of inter-channel interference and channel noise, comprising:
a vector generating circuit for creating a vector with zeroes and inserting average path gains in associated delay locations; and an equalization circuit for calculating equalization coefficients.