Trellis coding with one-bit constellations
US6622282B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 2001 |
| Grant date | Sep 16, 2003 |
| Priority date | — |
| Expiry date | Apr 4, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2602
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method for combining trellis-coded modulation with one-bit constellations to make more efficient use of available channel capacity in discrete multitone (DMT) asymmetric digital subscriber line (ADSL) systems. Through fine transmit gain adjustment, in individual tones, DMT systems are able to compensate for truncation effects in bits-per-tone loading. However, the allowed fine gain adjustment range is insufficient to compensate for the DMT requirement that data modulated tones carry at least two bits. Therefore, by allowing data-modulated tones to carry a single bit, the available channel capacity can be more efficiently utilized. Additionally, one-bit constellations may be combined with trellis coded modulation. A pair of one-bit sub-carrier may be considered as a virtual two-bit sub-carrier in the trellis encoder with the resulting encoded bit pair transmitted on the original sub-carriers using one-bit constellations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.