System and method for reducing peak-to-average ratio (PAR) values

1. In a digital subscriber line (DSL) system employing discrete multi-tone (DMT) technology, wherein a bandwidth is divided into a plurality of discrete symbols, a method for reducing peak-to-average ratio (PAR) values comprising:

(a) dividing the plurality of discrete symbols into non-overlapping subsets of symbols, wherein an aggregation of the non-overlapping subsets of symbols produces the plurality of discrete symbols;

(b) generating sub-sequences from the non-overlapping subsets of symbols by performing an inverse Fourier transform (IFT) on each of the non-overlapping subsets of symbols;

(c) combining the generated sub-sequences using a binary vector to produce a combined sequence, wherein the binary vector has a number of elements equal to the number of sub-sequences, wherein the binary vector is an arrangement of elements, wherein the elements are either +1 or −1;

(d) appending a pattern signal to the combined sequence to produce a patterned sequence, wherein the pattern signal corresponds to the arrangement of elements in the binary vector;

(e) adding a cyclic prefix to the patterned sequence to produce a prefixed sequence;

(f) adding a suffix to the prefixed sequence to produce a suffixed sequence;

(g) upsampling the suffixed sequence to produce an interpolated sequence;

(h) calculating a peak-to-average ratio (PAR) value of the interpolated sequence;

(i) storing the calculated PAR value of the interpolated sequence;

(j) iteratively repeating steps (c) through (i) to produce a plurality of binary vectors and a plurality of calculated PAR values, wherein each iteration uses a binary vector having a different arrangement of elements, wherein the iteration of steps (c) through (i) terminates when every different arrangement of elements has been used to combine the generated sub-sequences;

(k) determining the lowest PAR value from the calculated PAR values;

(l) selecting an optimal binary vector from the plurality of binary vectors, wherein the optimal binary vector is the binary vector corresponding to the lowest PAR value;

(m) combining the generated sub-sequences using the optimal binary vector to produce an optimal combined sequence;

(n) adding a cyclic prefix to the optimal combined sequence to produce an optimal prefixed sequence;

(o) adding a suffix to the optimal prefixed sequence to produce an optimal PAR sequence; and

(p) transmitting the optimal PAR sequence.

2. A system for reducing peak-to-average ratio (PAR) values comprising:

a symbol divider configured to divide a plurality of symbols into a number of non-overlapping subsets of symbols, wherein the aggregation of the non-overlapping subsets of symbols produces the plurality of symbols;

inverse Fourier transform (IFT) logic configured to perform an IFT on each of the non-overlapping subsets of symbols to produce a plurality of sub-sequences;

linear vector generator configured to generate a linear vector having a number of elements, wherein the number of elements in the generated linear vector is the same as the number of sub-sequences in the plurality of sub-sequences;

a multiplier configured to multiply the generated linear vector with the plurality of sub-sequences to produce a combined sequence;

a resampler configured to upsample the combined sequence to produce an interpolated sequence;

PAR calculator configured to calculate the PAR value of the interpolated sequence;

a prefix generator configured to generate a cyclic prefix, wherein the cyclic prefix is configured to reduce intersymbol interference, wherein the values of the cyclic prefix are the end values of the combined sequence;

memory configured to store the calculated PAR value

a comparator configured to compare a plurality of stored PAR values wherein the comparator is further configured to determine a lowest PAR value from the compared plurality of stored PAR values;

a correlator configured to correlate the determined lowest PAR value with a linear vector;

a pattern generator configured to generate a pattern indicative of the linear vector; and

append logic configured to append the generated pattern to the linear vector.

3. The system of claim 2 , wherein the append logic is further configured to append the cyclic prefix to the beginning of the linear vector.

4. The system of claim 2 , further comprising a suffix generator configured to generate a suffix, wherein the suffix is configured to reduce effects of intersymbol boundary conditions.

5. The system of claim 4 , wherein the append logic is further configured to append the suffix to the end of the linear vector.

6. A method for reducing peak-to-average ratio (PAR) values comprising:

(a) dividing a plurality of symbols into a number of non-overlapping subsets of symbols, wherein an aggregation of the non-overlapping subsets of symbols produces the plurality of symbols;

(b) performing an inverse Fourier transform (IFT) on each of the non-overlapping subsets of symbols to produce a plurality of sub-sequences;

(c) multiplying the plurality of sub-sequences with a linear vector having a number of elements to produce a combined sequence, wherein the number of elements in the linear vector is the same as the number of sub-sequences;

(d) upsampling the combined sequence to produce an interpolated sequence;

(e) calculating the peak-to-average ratio (PAR) value of the interpolated sequence;

(f) appending a pattern signal to interpolated sequence to produce a patterned sequence, wherein the pattern signal is indicative of linear vector;

(g) storing the calculated PAR value; and

(h) iteratively repeating steps (c) through (g) to produce a plurality of stored PAR values, wherein each iteration uses a different linear vector in the step of (c) multiplying the plurality of sub-sequences with a linear vector, wherein each of the plurality of stored PAR values corresponds to a different linear vector.

7. The method of claim 6 , further comprising:

(i) determining the lowest PAR value from the plurality of stored PAR values.

8. The method of claim 7 , further comprising:

(j) ascertaining the linear vector corresponding to the determined lowest PAR value.

9. The method of claim 7 , further comprising:

(k) multiplying the plurality of sub-sequences with the ascertained linear vector to produce an optimal PAR-value sequence.

10. The method of claim 9 , further comprising:

(l) adding an optimal pattern signal to the optimal PAR-value sequence to produce an optimal patterned sequence, wherein the optimal pattern signal corresponds to the ascertained linear vector.

11. The method of claim 10 , further comprising:

(m) transmitting the optimal patterned sequence.

12. The method of claim 11 , further comprising:

(n) receiving the optimal patterned sequence;

(o) extracting the pattern signal from the optimal patterned sequence; and

(p) reconstructing the sub-sequences using the extracted pattern signal.

13. The method of claim 6 , wherein the linear vector is a binary vector.

14. The method of claim 13 , wherein each element of the binary vector is either +1 or −1.

15. A method for reducing peak-to-average ratio (PAR) values comprising:

(a) dividing a plurality of symbols into a number of non-overlapping subsets of symbols, wherein an aggregation of the non-overlapping subsets of symbols produces the plurality of symbols;

(b) performing an inverse Fourier transform (IFT) on each of the non-overlapping subsets of symbols to produce a plurality of sub-sequences;

(c) multiplying the plurality of sub-sequences with a linear vector having a number of elements to produce a combined sequence, wherein the number of elements in the linear vector is the same as the number of sub-sequences;

(d) adding a cyclic prefix to the combined sequence to produce a prefixed sequence;

(e) upsampling the prefixed sequence to produce an interpolated sequence;

(f) calculating the peak-to-average ratio (PAR) value of the interpolated sequence;

(g) appending a pattern signal to the interpolated sequence to produce a patterned sequence, wherein the pattern signal corresponds to the linear vector;

(h) storing the calculated PAR value; and

(i) iteratively repeating steps (c) through (h) to produce a plurality of stored PAR values, wherein each iteration uses a different linear vector in the step of (c) multiplying the plurality of sub-sequences with a linear vector, wherein each of the plurality of stored PAR values corresponds to a different linear vector.

16. The method of claim 15 , further comprising:

(j) determining the lowest PAR value from the plurality of stored PAR values;

(k) ascertaining the linear vector corresponding to the determined lowest PAR value;

(l) multiplying the plurality of sub-sequences with the ascertained linear vector to produce an optimal PAR-value sequence; and

(m) adding an optimal pattern signal to the optimal PAR-value sequence to produce an optimal patterned sequence, wherein the optimal pattern signal corresponds to the ascertained linear vector.

17. The method of claim 15 , wherein the cyclic prefix is configured to reduce an intersymbol interference.

18. The method of claim 15 , wherein the values of the cyclic prefix are the end values of the combined sequence.

19. A method for reducing peak-to-average ratio (PAR) values comprising:

(a) dividing a plurality of symbols into a number of non-overlapping subsets of symbols, wherein an aggregation of the non-overlapping subsets of symbols produces the plurality of symbols;

(b) performing an inverse Fourier transform (IFT) on each of the non-overlapping subsets of symbols to produce a plurality of sub-sequences;

(c) multiplying the plurality of sub-sequences with a linear vector having a number of elements to produce a combined sequence, wherein the number of elements is the same as the number of sub-sequences;

(d) adding a cyclic prefix to the combined sequence to produce a prefixed sequence;

(e) adding a suffix to the prefixed sequence to produce a suffixed sequence;

(f) upsampling the suffixed sequence to produce an interpolated sequence;

(g) calculating the peak-to-average ratio (PAR) value of the interpolated sequence;

(h) appending a pattern signal to the interpolated sequence to produce a patterned sequence, wherein the pattern signal corresponds to the linear vector;

(i) storing the calculated PAR value; and

(j) iteratively repeating steps (c) through (i) to produce a plurality of stored PAR values wherein each iteration uses a different linear vector in the step of (c) multiplying the plurality of sub-sequences with a linear vector wherein each of the plurality of stored PAR values corresponds to a different linear vector.

20. The method of claim 19 , further comprising:

(k) determining the lowest PAR value from the plurality of stored PAR values;

(l) ascertaining the linear vector corresponding to the determined lowest PAR value;

(m) multiplying the plurality of sub-sequences with the ascertained linear vector to produce an optimal PAR-value sequence; and

(n) adding an optimal pattern signal to the optimal PAR-value sequence to produce an optimal patterned sequence, wherein the optimal pattern signal corresponds to the ascertained linear vector.

21. The method of claim 19 , wherein the suffix is configured to reduce effects of intersymbol boundary conditions.

22. A system for reducing peak-to-average ratio (PAR) values comprising:

(a) means for dividing a plurality of symbols into a number of non-overlapping subsets of symbols, wherein an aggregation of the non-overlapping subsets of symbols produces the plurality of symbols;

(b) means for performing an inverse Fourier transform (IFT) on each of the non-overlapping subsets of symbols to produce a plurality of sub-sequences;

(c) means for multiplying the plurality of sub-sequences with a linear vector having a number of elements to produce a combined sequence, wherein the number of elements in the linear vector is the same as the number of sub-sequences wherein the linear vector is a binary vector wherein each element of the binary vector is either +1 or −1;

(d) means for upsampling the combined sequence to produce an interpolated sequence;

(e) means for calculating the peak-to-average ratio (PAR) value of the interpolated sequence; and

(f) means for appending a pattern signal to interpolated sequence to produce a patterned sequence, wherein the pattern signal is indicative of linear vector; and

(g) means for storing the calculated PAR value.

23. A system for reducing peak-to-average ratio (PAR) values comprising:

(a) means for dividing a plurality of symbols into a number of non-overlapping subsets of symbols, wherein an aggregation of the non-overlapping subsets of symbols produces the plurality of symbols;

(b) means for performing an inverse Fourier transform (IFT) on each of the non-overlapping subsets of symbols to produce a plurality of sub-sequences;

(c) means for multiplying the plurality of sub-sequences with a linear vector having a number of elements to produce a combined sequence, wherein the number of elements in the linear vector is the same as the number of sub-sequences;

(d) means for adding a cyclic prefix to the combined sequence to produce a prefixed sequence, wherein the values of the cyclic prefix are the end values of the combined sequence;

(e) means for upsampling the prefixed sequence to produce an interpolated sequence;

(f) means for calculating the peak-to-average ratio (PAR) value of the interpolated sequence;

(g) means for appending a pattern signal to the interpolated sequence to produce a patterned sequence, wherein the pattern signal corresponds to the linear vector;

(h) means for storing the calculated PAR value,

(i) means for determining a lowest PAR value from a plurality of stored PAR values;

(j) means for ascertaining a linear vector corresponding to the determined lowest PAR value;

(k) means for multiplying the plurality of sub-sequences with the ascertained linear vector to produce an optimal PAR-value sequence; and

(l) means for adding an optimal pattern signal to the optimal PAR-value sequence to produce an optimal patterned sequence wherein the optimal pattern signal corresponds to the ascertained linear vector.

24. The system of claim 23 , wherein the cyclic prefix is configured to reduce an intersymbol interference.

25. A system for reducing peak-to-average ratio (PAR) values comprising:

(a) means for dividing a plurality of symbols into a number of non-overlapping subsets of symbols, wherein an aggregation of the non-overlapping subsets of symbols produces the plurality of symbols;

(b) means for performing an inverse Fourier transform (IFT) on each of the non-overlapping subsets of symbols to produce a plurality of sub-sequences;

(c) means for multiplying the plurality of sub-sequences with a linear vector having a number of elements to produce a combined sequence, wherein the number of elements is the same as the number of sub-sequences;

(d) means for adding a cyclic prefix to the combined sequence to produce a prefixed sequence;

(e) means for adding a suffix to the prefixed sequence to produce a suffixed sequence;

(f) means for upsampling the suffixed sequence to produce an interpolated sequence;

(g) means for calculating the peak-to-average ratio (PAR) value of the interpolated sequence; and

(h) means for appending a pattern signal to the interpolated sequence to produce a patterned sequence, wherein the pattern signal corresponds to the linear vector;

(i) means for storing the calculated PAR value;

(j) means for determining a lowest PAR value from a plurality of stored PAR values;

(k) means for ascertaining a linear vector corresponding to the determined lowest PAR value;

(l) means for multiplying the plurality of sub-sequences with the ascertained linear vector to produce an optimal PAR-value sequence; and

(m) means for adding an optimal pattern signal to the optimal PAR-value sequence to produce an optimal patterned sequence wherein the optimal pattern signal corresponds to the ascertained linear vector.

26. The system of claim 25 , wherein the suffix is configured to reduce effects of intersymbol boundary conditions.