Method and apparatus for calculating bit log-likelihood ratios for QAM signals
US6834088B2 · kind B2 · utility
16Cited by
3References
16Claims
0Family size
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Key dates
| Filing date | Mar 12, 2001 |
| Grant date | Dec 21, 2004 |
| Priority date | — |
| Expiry date | Mar 2, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/067
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method and apparatus to efficiently calculate log-likelihood ratios for each bit within M-ary QAM modulated symbols transmitted in a communication system. The method and apparatus utilize characteristics of square Karnaugh mapping of the QAM symbol constellation in order to reduce the number of distance calculations needed to determine the log-likelihood ratios for each of the bits within a demodulated symbol. The reduction in the number of calculations affords significant reduction in the time needed to determine log-likelihood ratios, especially for higher order M-ary QAM systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.