Block oriented digital communication system and method
AssigneeIntellon Corporation
InventorsJohn Louis Fanson, Douglas Hamilton Taylor
Life of this patent
Estimating the term…
Abstract
A method and system for estimating a time shift required for symbol synchronization in a block oriented digital communication systems such as an orthogonal frequency division multiplexing (OFDM) or a discrete multi-tone (DMT) data transmission system. The method uses an N/d inverse discrete Fourier transform (IDFT), where N is a sample number and d is a decimation factor, or alternatively an N/(2d) inverse fast Fourier transform (IFFT) for a real received signal or an N/d IDFT for a complex received signal.
Claims56
A method for estimating a time shift required for symbol synchronization in a block oriented digital communication system for receiving PHY symbols, the method comprising steps of:
- producing a first sequence (u(n)) by sampling a received real signal N times over a duration of one PHY symbol;
- producing a second sequence (U(k)) by performing an N point discrete Fourier transform (DFT) on u(n);
- producing a third sequence (Y(k)) by multiplying U(k) by a fourth sequence (S*(k)) comprising a complex conjugate of a DFT of a synch symbol;
- producing a fifth sequence (Y′(k)) by multiplying Y(k) by a window of length N/(2d) from k1 to k1+N/(2d)−1 where d is a decimation factor and 0≦k1≦N/2−N/(2d);
- producing a sixth sequence (Y″(k)) by shifting Y′(k) by k1 samples;
- producing a seventh sequence (X(k)) by forming a conjugate symmetric spectrum from Y″(k);
- producing a eighth sequence (x(n)) by performing an N/d inverse DFT (IDFT) of X(k);
- and
- estimating the time shift required for symbol synchronization by detecting a position in time of a peak value in x(n).
A method for estimating a time shift required for symbol synchronization in a block oriented digital communication system comprising PHY symbols, the method comprising steps of:
- producing a first sequence (u(n)) of by sampling a received complex signal N times over a duration of one PHY symbol;
- producing a second sequence (U(k)) by performing an N point discrete Fourier transform (DFT) on u(n);
- producing a third sequence (Y(k)) by multiplying U(k) by a fourth sequence (S*(k)) comprising a complex conjugate of a DFT of a synch symbol;
- producing a fifth sequence (Y′(k)) by multiplying Y(k) by a window of length N/(d) from k1 to k1+N/(d)−1 where d is a decimation factor and 0≦k1≦N−N/(d);
- producing a sixth sequence (X(k)) by shifting Y′(k) by k1 samples;
- producing a seventh sequence (x(n)) by performing an N/d inverse DFT (IDFT) of X(k);
- and
- estimating the time shift required for symbol synchronization by detecting a position in time of a peak value in x(n).
A block oriented digital communication system for receiving PHY symbols, comprising:
- means for producing a first sequence (u(n)) of by sampling a received real signal N times over a duration of one PHY symbol;
- means for producing a second sequence (U(k)) by performing an N point discrete Fourier transform (DFT) on u(n);
- means for producing a third sequence (Y(k)) by multiplying U(k) by a fourth sequence (S*(k)) comprising a complex conjugate of a DFT of a synch symbol;
- means for producing a fifth sequence (Y′(k)) by multiplying Y(k) by a window of length N/(2d) from k1 to k1+N/(2d)−1 where d is a decimation factor and 0≦k1≦N/2−N/(2d);
- means for producing a sixth sequence (Y″(k)) by shifting Y′(k) by k1 samples;
- means for producing a seventh sequence (X(k)) by forming a conjugate symmetric spectrum from Y″(k);
- means for producing a eighth sequence (x(n)) by performing an N/d inverse DFT (IDFT) of X(k);
- and
- means for estimating a time shift required for symbol synchronization by detecting a position in time of a peak value in x(n).
A block oriented digital communication system for receiving PHY symbols, comprising:
- means for producing a first sequence (u(n)) of by sampling a received complex signal N times over a duration of one PHY symbol;
- means for producing a second sequence (U(k)) by performing an N point discrete Fourier transform (DFT) on u(n);
- means for producing a third sequence (Y(k)) by multiplying U(k) by a fourth sequence (S*(k)) comprising a complex conjugate of a DFT of a synch symbol;
- means for producing a fifth sequence (Y′(k)) by multiplying Y(k) by a window of length N/(d) from k1 to k1+N/(d)−1 where d is a decimation factor and 0≦k1≦N−N/(d);
- means for producing a sixth sequence (X(k)) by shifting Y′(k) by k1 samples;
- means for producing a seventh sequence (x(n)) by performing an N/d inverse DFT (IDFT) of X(k);
- and
- means for estimating a time shift required for symbol synchronization by detecting a position in time of a peak value in x(n).
Dependencies are inferred from the claim text.