Combined equalization for DMT-based modem receiver
US7133444B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 2002 |
| Grant date | Nov 7, 2006 |
| Priority date | — |
| Expiry date | Dec 14, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03484
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A DMT modem (40) is disclosed, in which a combined time domain equalizer and per-tone equalizer is applied to a received DMT signal. The combined equalizer includes a first FFT function (44) that is applied to a set of samples in a time-domain signal after the application of a time domain equalizer (42). The first FFT function (44) produces an initial FFT result, that is accumulated with a sliding FFT (46) performed upon difference values in the time domain samples. The sliding FFT results are applied to a per-ton equalizer (48) which applies a set of complex coefficients determined in training of the modem. A simple 1-tap FEQ (50) then can recover the signal. The combined equalizer enables per-tone equalization, in a manner that is compatible with conventional DSL training standards. According to a second embodiment, the per-tone equalization is performed only on selected tones of the multitone signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.