Correlation based method of determining frame boundaries of data frames that are periodically extended
First Claim
Patent Images
1. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
- forming a sample sequence from a received multicarrier signal;
calculating a difference sequence from the sample sequence, wherein the sample sequence is y[n], and the step of forming the difference sequence, z[n], is performed in accordance with the relationship;
z[n]=|y[n]−
y[n+N]|, wherein N, an integer, is the number of samples in a symbol, and n is an integer index;
forming a window sequence from selected points within the difference sequence;
forming a summation sequence by summing selected points within the summation sequence;
locating the minimum value of the window sequence; and
loading a pointer register based on a sequence index corresponding to a maximum value.
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Abstract
A correlator for use in a timing recovery apparatus of a receiver in a multicarrier transmission system. The correlator locates the beginning of a data frame and initializes a pointer register with an address to a location within the receive signal buffer. Data is transferred to a signal converter from the receive signal buffer where the samples that are fed into the converter are determined by the address stored in the pointer register.
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Citations
13 Claims
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1. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
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forming a sample sequence from a received multicarrier signal;
calculating a difference sequence from the sample sequence, wherein the sample sequence is y[n], and the step of forming the difference sequence, z[n], is performed in accordance with the relationship;
z[n]=|y[n]−
y[n+N]|, wherein N, an integer, is the number of samples in a symbol, and n is an integer index;
forming a window sequence from selected points within the difference sequence;
forming a summation sequence by summing selected points within the summation sequence;
locating the minimum value of the window sequence; and
loading a pointer register based on a sequence index corresponding to a maximum value. - View Dependent Claims (2, 3)
where M+P is the length of a periodic extension, M is the length of a communication channel impulse response, i is an integer index, j is an integer index, P is an integer representing the difference between M and the length of the periodic extension, and {circumflex over (P)} is an integer where 0<
{circumflex over (P)}≦
P.
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3. The method of claim 2 wherein the step of forming a summation sequence, w[n] is formed in accordance with the relation:
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and Q is a number of frames being processed.
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4. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
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forming a sample sequence from a received multicarrier signal;
calculating a difference sequence from the sample sequence, wherein the sample sequence is y[n], and the step of forming the difference sequence, z[n], is performed in accordance with the relationship;
z[n]=|y[n]−
y[n+N]|, where N, an integer, is the number of samples in a symbol, and n is an integer index;
forming a window sequence by weighting and summing selected points within the difference sequence;
locating the minimum value of the window sequence; and
loading a pointer register based on a sequence index corresponding to the minimum value. - View Dependent Claims (5)
wherein R is an integer offset, hMF is a matched filter, and k is an integer index.
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6. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
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forming a sample sequence from a received multicarrier signal;
calculating a difference sequence from the sample sequence, wherein the sample sequence is y[n], and the step of forming the difference sequence, z[n], is performed in accordance with the relationship;
z[n]=zmax−
|y[n]−
y[n+N]|, where zmax is the maximum value of |y[n]−
y[n+N]|, N, an integer, is the number of samples in a symbol, and n is an integer index;
forming a window sequence by weighting and summing selected points within the difference sequence;
locating the maximum value of the window sequence; and
loading a pointer register based on a sequence index corresponding to the maximum value. - View Dependent Claims (7)
where R is an integer offset, hMF is a matched filter, and k in an integer index.
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8. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
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forming a sample sequence from a received multicarrier signal;
calculating a difference sequence for a window of values from the sample sequence, wherein the sample sequence is y[n], and the step of forming the difference sequence and comparing to a minimum value is performed in accordance with the relationship;
∀
m∈
[0,{circumflex over (P)}−
1],|y[n+m]−
y[n+m+N]|≦
ε
, where N, an integer, is the number of samples in a symbol, ε
is the minimum value to which the sequence is compared, {circumflex over (P)}, is an integer, where 0<
{circumflex over (P)}≦
P, and P is an integer number of samples that is a measure by which a periodic extension exceeds a channel impulse response;
comparing the difference sequence to a minimum value; and
loading a pointer register based on a minimum sequence index corresponding to the minimum value.
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9. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
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forming a sample sequence from a received multicarrier signal;
calculating a difference sequence for a window of values from the sample sequence, wherein the sample sequence is y[n], and the step of forming the difference sequence and comparing to a maximum value is performed in accordance with the relationship;
∀
m∈
[0,{circumflex over (P)}−
1],[zmax−
|y[n+m]−
y[n+m+N]|]≦
ε
, where N, an integer, is the number of symbol samples, n is an integer index, m is an integer index, ε
is the maximum value to which the sequence is compared, {circumflex over (P)}, is an integer, where 0<
{circumflex over (P)}≦
P, and P is an integer number of samples that is a measure by which a periodic extension exceeds a channel impulse response;
comparing the difference sequence to a value; and
loading a pointer resister based on a minimum sequence index corresponding to a maximum value.
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10. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
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forming a sample sequence from a received multicarrier signal;
calculating a difference sequence from the sample sequence, wherein the sample sequence is y[n], and the step of forming the difference sequence, z[n], is performed in accordance with the relationship;
where N, an integer, is the number of samples in a symbol, l is an integer index, n is an integer index, {circumflex over (P)}, is an integer, where 0<
{circumflex over (P)}≦
P, and P is an integer number of samples that is a measure by which a periodic extension exceeds a channel impulse response;forming a window sequence by weighting and summing selected points within the difference sequence;
locating the maximum value of the window sequence; and
locating a pointer register based on a sequence index corresponding to the maximum value.
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11. A method of determining a symbol frame boundary in a multicarrier data signal, comprising the steps of:
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forming a sample sequence from a received multicarrier signal;
calculating a difference sequence, z[n], from the sample sequence, wherein the sample sequence is y[n], and the step of calculating the difference sequence is performed in accordance with the relationship;
z[n]=zmax−
|y[n]−
y[n+N]|, where zmax is the maximum value of |y[n]−
y[n+N]|, N, an integer, is the number of samples in a frame, and n is an integer index;
forming a multiplicative estimate sequence from selected points within the difference sequence;
forming a window sequence by summing selected points within the product sequence;
locating the maximum value of the window sequence; and
loading a pointer register based on the sequence index corresponding to the maximum value. - View Dependent Claims (12, 13)
wherein Q is the number of frames being processed, M+P is the length of a periodic extension, M is the length of a communication channel impulse response, P is an integer number of samples that is a measure by which the periodic extension exceeds the channel impulse response, i is an integer index, and j is an integer index.
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13. The method of claim 12, wherein the step of forming a window sequence, w[n] is performed in accordance with the relationship:
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where {circumflex over (P)} is an integer and 0<
{circumflex over (P)}≦
P.
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Specification