Blind decoding in orthogonal frequency division multiplexing (OFDM) communication systems
First Claim
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1. A communication device for blind decoding of an incoming orthogonal frequency division multiplexing (OFDM) signal, the communication device comprising:
- a receiver circuit comprising;
a frequency tracking offset circuit adapted to provide frequency corrections to the incoming OFDM signal due to frequency offset errors; and
a blind physical layer control (PLC) detection circuit coupled to the frequency tracking offset circuit and adapted to turn off the frequency tracking offset circuit for a first plurality of OFDM symbols of the incoming OFDM signal to determine a frequency displacement misalignment between a transmit inverse fast Fourier transform (iFFT) and a receive FFT and to turn on the frequency tracking offset circuit to apply frequency corrections excluding said frequency displacement.
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Abstract
Methods and architectures for blind detection of physical layer control (PLC) signaling for transmitters and receivers having respective misaligned inverse fast Fourier transforms (IFFTs) and (FFTs) includes opening a frequency tracking offset calibration circuit, estimating or calculating a phase discontinuity due to FFT misalignment, closing the frequency tracking offset calibration circuit and applying a frequency correction that includes a frequency offset less the calculated or estimated phase discontinuity.
42 Citations
14 Claims
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1. A communication device for blind decoding of an incoming orthogonal frequency division multiplexing (OFDM) signal, the communication device comprising:
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a receiver circuit comprising; a frequency tracking offset circuit adapted to provide frequency corrections to the incoming OFDM signal due to frequency offset errors; and a blind physical layer control (PLC) detection circuit coupled to the frequency tracking offset circuit and adapted to turn off the frequency tracking offset circuit for a first plurality of OFDM symbols of the incoming OFDM signal to determine a frequency displacement misalignment between a transmit inverse fast Fourier transform (iFFT) and a receive FFT and to turn on the frequency tracking offset circuit to apply frequency corrections excluding said frequency displacement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of blind decoding a physical link layer control (PLC) signal from an incoming orthogonal frequency division multiplexing (OFDM) signal, the method comprising:
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deactiviating a frequency correction tracking loop during an initial plurality of symbols received from the incoming OFDM signal; calculating a frequency displacement between fast Fourier transforms (FFTs) used by a transmitter and a receiver; determining a frequency correction to be used by the frequency correction as an offset correction less the calculated frequency displacement; reactivating the frequency correction tracking loop to apply the frequency correction; and recovering the PLC signal after the frequency correction. - View Dependent Claims (11, 12, 13, 14)
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Specification