Timing synchronization in OFDM communications receivers
AssigneeSymbol Technologies, Inc.
InventorRobert Ward
Life of this patent
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Abstract
An orthogonal frequency division multiplexing (OFDM) receiver is synchronized to a received signal during one of the short symbols of the preamble of the OFDM signal, using a timing synchronizing circuit that derives timing information from timing components generated by a constellation processing circuit which generates the timing components from frequency domain components obtained by performing a Fourier transform on the OFDM signal.
Claims13
A method of synchronizing a receiver to a received orthogonal frequency division multiplexing (OFDM) signal having a preamble with short and long duration symbols, comprising the steps of:
- a) converting the received OFDM signal by Fourier transform to frequency domain components;
- b) processing the frequency domain components to timing components;
- c) deriving timing information from the timing components;
- d) applying the timing information to the received OFDM signal to synchronize the receiver;
- and
- e) all of said steps being performed during one of the short symbols.
A method of antenna selection in a dual antenna receiver for receiving an orthogonal frequency division multiplexing (OFDM) signal having a preamble with short and long duration symbols, comprising the steps of:
- a) converting an OFDM signal received by a first antenna by Fourier transform to frequency domain components;
- b) processing the frequency domain components to timing components;
- c) deriving timing information from the timing components;
- d) applying the timing information to the received OFDM signal to synchronize the receiver;
- e) analyzing a signal-to-noise ratio (SNR) of the OFDM signal received by the first antenna of the synchronized receiver during one of the short symbols;
- f) repeating steps a) through e) for a second antenna during another of the short symbols;
- and
- g) selecting the antenna which has a higher SNR during another of the short symbols.
An arrangement for synchronizing a receiver to a received orthogonal frequency division multiplexing (OFDM) signal having a preamble with short and long duration symbols, comprising:
- a) a Fourier transform (FT) circuit for converting the received OFDM signal to frequency domain components;
- b) a constellation processing (CP) circuit connected to the FT circuit, for processing the frequency domain components to timing components;
- and
- c) a timing synchronizing circuit connected to the CP circuit, and operative for deriving timing information from the timing components, and for applying the timing information to the received OFDM signal to synchronize the receiver during one of the short symbols.
Dependencies are inferred from the claim text.