Dual-Carrier Modulation Decoder

• US 20070091984A1
• Filed: 10/23/2006
• Published: 04/26/2007
• Est. Priority Date: 10/24/2005
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Batra, Anuj, Balakrishnan, Jaiganesh, Lingam, Srinivas
• Application Number:
  US11/551,980
• Publication Number:
  US 20070091984A1
• Time in Patent Office: Days
• US Class Current: 375/130
• CPC Class Codes: H04B 1/7176 Data mapping, e.g. modulation
• CPC Class Codes: H04L 27/3405 Modifications of the signal space to increase the efficiency of transmission, e.g. reduction of the bit error rate, bandwidth, or average power
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

Communications systems are disclosed which comprise system and methods which, in some embodiments, include a data input; a decoding function, which is adapted to receive a first data element and a second data element from the data input and decode the first data element and second data element, and a mapping element, which is adapted to map the first data element and second data element onto two constellations.

Claims

1. An ultra-wideband wireless communications system comprising:

a data input;

a decoding function, adapted to receive a first data element and a second data element from the data input and decode the first data element and second data element;

a mapping element, adapted to map the first data element and second data element onto a first constellation and a second constellation; and

a log likelihood function operable to substantially maximize log likelihood information across a first tone and a second tone using the first constellation and the second constellation.

2. The system of claim 1, wherein the first data element is a tone.

3. The system of claim 1, further comprising an ordering function that is capable of taking the order of the received elements into consideration.

4. The system of claim 3, further comprising a recovery function that is capable of extrapolating the corrected data element from the constellation.

5. The system of claim 3, wherein the log likelihood function further comprises a block code, turbo code, convolutional code, Reed Solomon code, or combination thereof.

6. The system of claim 3, wherein the coding function further comprises a convolutional code of an [R=⅓

, k=7] form.

7. The system of claim 1, wherein the log likelihood function is selected from the group of functions:

$\begin{array}{c}\mathrm{LLR}<br><br>\left(b_{2<br><br>k}\right)=\max <br><br>\{\left[3<br><br>\mathrm{Re}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)-\mathrm{Re}<br><br>\left(y_{k+50}\right)\right],\hspace{1em}<br><br>\left[2<br><br>\mathrm{Re}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+\mathrm{Re}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right]\}-\max <br><br>\left\{\left[\mathrm{Re}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+2<br><br>\mathrm{Re}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right],0\right\}.,\\ \mathrm{LLR}<br><br>\left(b_{2<br><br>k+100}\right)=\max <br><br>\{\left[3<br><br>\mathrm{Re}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)-\mathrm{Re}<br><br>\left(y_{k+50}\right)\right],\hspace{1em}<br><br>\left[\mathrm{Re}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+2<br><br>\mathrm{Re}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right]\}-\max <br><br>\left\{\left[2<br><br>\mathrm{Re}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+\mathrm{Re}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right],0\right\}.,\\ \mathrm{LLR}<br><br>\left(b_{2<br><br>k+1}\right)=\max <br><br>\{\left[3<br><br>\mathrm{Im}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)-\mathrm{Im}<br><br>\left(y_{k+50}\right)\right],\hspace{1em}<br><br>\left[2<br><br>\mathrm{Im}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+\mathrm{Im}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right]\}-\max <br><br>\left\{\left[\mathrm{Im}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+2<br><br>\mathrm{Im}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right],0\right\}.,<br><br>\mathrm{and}\\ \mathrm{LLR}<br><br>\left(b_{2<br><br>k+101}\right)=\max <br><br>\{\left[3<br><br>\mathrm{Im}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)-\mathrm{Im}<br><br>\left(y_{k+50}\right)\right],\hspace{1em}<br><br>\left[\mathrm{Im}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+2<br><br>\mathrm{Im}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right]\}-\max <br><br>\left\{\left[2<br><br>\mathrm{Im}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(y_k\right)+\mathrm{Im}<br><br>\left(y_{k+50}\right)+2/\sqrt{5}<br><br>\left({<br><br>h_k<br><br>}^2-{<br><br>h_{k+50}<br><br>}^2\right)\right],0\right\}..\end{array}$

8. A method for network communications, comprising:

receiving data with a first data pair and a second data pair;

reconstructing the data by considering a separation between the transmission of the first data pair and the second data pair;

creating two constellations using the data reconstructed;

detecting an error in the first data pair; and

recovering at least part of first data pair using the second data pair.

9. The method of claim 8, wherein each of the constellations is made up of sixteen points.

10. The method of claim 8, wherein the delay between the transmission of the first data pair and the second data pair is fifty tones.

11. The method of claim 8, wherein the network is a WiMedia network.

12. A dual-carrier modulation decoder containing instructions operable when executed to perform a method comprising:

receiving a signal containing a tone pair without frequency spreading or time spreading;

reordering the signal to account for any intermediate tones transmitted in between the tone pair; and

decoding the signal.

13. The dual-carrier modulation decoder of claim 12, wherein the decoding of a signal further comprises detecting an error within the signal.

14. The dual-carrier modulation decoder of claim 13, wherein the decoding of a signal is preformed through a exact process using the log-likelihood approximation.

15. The dual-carrier modulation decoder of claim 13, wherein the decoding of a signal is preformed through an inexact process.

16. The dual-carrier modulation decoder of claim 12, further comprising recovering from an error within the signal.

17. The dual-carrier modulation decoder of claim 15, wherein the decoding of a signal is preformed through a log-likelihood approximation.

18. The dual-carrier modulation decoder of claim 17, wherein the log-likelihood approximation is decomposed into log(exp(A)+exp(B)) and log(exp(X)+exp(Y)).

19. The dual-carrier modulation decoder of claim 17, wherein the log-likelihood approximation is simplified to log(max{exp(A),exp(B)}).

20. The dual-carrier modulation decoder of claim 12, wherein the signal is received over an OFDM-based data transmission network.