Method and apparatus for initializing modem communications
US7035326B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 8, 2002 |
| Grant date | Apr 25, 2006 |
| Priority date | — |
| Expiry date | Apr 25, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/1438
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention provides a method and apparatus for demodulating data received over a communication medium carrying a transmission having multiple pilot tones with pilot data modulated thereon and message tones with message data modulated thereon and with the pilot tones and message tones frequency division multiplexed with respect to one another. In an embodiment of the invention the communication protocol utilized for modulation and demodulation is discrete multi tone (DMT). The invention allows message processing and equalizer training to proceed in parallel before equalizer training tables have been completed thus reducing the time associated with modem initialization. The apparatus in one embodiment of the invention includes on the receive path of a DMT or other multi-tone modem, a fast Fourier transform engine (FFT), a message processor, and a decoder. The FFT converts the received data from a time domain to a frequency domain. The received data in the frequency domain includes successive sets of pilot tones together with message tones. The message processor selects pairs of message and pilot tones proximate to one another in the frequency domain in each set of pilot to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.