Patent ID: 9497056
Filing Date: 2016-11-15
CPC Classification: H04B,H04L

Claim Text:
1. A receiver apparatus for interleaved forward-error-correction coded digital signals as conveyed by their inverse fast Fourier transform (I-FFT) modulating respective coded-orthogonal-frequency-division-modulated (COFDM) carrier waves in most cells in each of successive orthogonal-frequency-division-modulation (OFDM) frames, a fraction of the cells in each of said successive OFDM frames constituting respective continual pilot carrier waves modulated in accordance with chips of one of cyclically repeated sequences of chips that is selected for identifying a respective one of a plurality of different COFDM transmission modes, said receiver comprising: a tuner for receiving and demodulating a selected radio-frequency signal to generate a baseband digitized COFDM signal; a unit for removing guard intervals from said baseband digitized COFDM signal; a computer for computing the fast Fourier transform (FFT) of said baseband digitized COFDM signal from which said guard intervals thereof have been removed, certain components of said FFT constituting respective continual ones of said pilot carrier waves modulated at least during initial portion of each successive COFDM frame in accordance with respective elements of said one of repetitive sequences selected for identifying a respective one of a plurality of different COFDM transmission modes; a frequency-domain channel equalizer connected for equalizing components of said FFT to counteract irregularities in the response of the transmission channel to these respective components, thus to generate complex coordinates of quadrature-amplitude-modulation (QAM) symbol constellations, said equalizing being performed responsive to the respective amplitudes of said continual pilot carrier waves; a demodulator of the modulation of one or more of said continual ones of said pilot carrier waves to generate a continual-pilot-carrier demodulation result; a first match filter configured to detect and identify each occurrence of a first sequence of cyclically repeated chips in said continual-pilot-carrier demodulation result, said first sequence of chips being cyclically repeated in such phasing as to specify at least in part a respective one of said plurality of different COFDM transmission modes that said receiver apparatus is capable of usefully receiving; apparatus for de-mapping said complex coordinates of said QAM symbol constellations to recover said interleaved forward-error-correction coded digital signals; and apparatus for decoding said forward-error-correction coded digital signals extracted from said interleaved forward-error-correction coded digital signals to recover said digital signals in systematic form.