Efficient demapping of constellations
US9391739B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 2015 |
| Grant date | Jul 12, 2016 |
| Priority date | — |
| Expiry date | Feb 9, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/0618
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus for efficient demapping of constellations are described. In an embodiment, these methods may be implemented within a digital communications receiver, such as a Digital Terrestrial Television receiver. The method reduces the number of distance metric calculations which are required to calculate soft information in the demapper by locating the closest constellation point to the received symbol. This closest constellation point is identified based on a comparison of distance metrics which are calculated parallel to either the I- or Q-axis. The number of distance metric calculations may be reduced still further by identifying a local minimum constellation point for each bit in the received symbol and these constellation points are identified using a similar method to the closest constellation point. Where the system uses rotated constellations, the received symbol may be unrotated before any constellation points are identified.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.