Method for fast off-line training for discrete multitone transmissions
AssigneeNational Semiconductor Corporation
InventorsOren Arad, Avi Gal, Boaz Efroni
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Abstract
A method of calculating TEQ and FEQ coefficients in a discrete multi-tone (DMT) system includes determining an estimated channel impulse response. A frame delay is determined based upon the estimated channel impulse response. Using these parameters and a known training sequence, the method generates the TEQ coefficients. The method then generates the FEQ coefficients based upon the TEQ coefficients and a version of the estimated channel impulse response.
Claims33
A method of operating a decoder in a DMT system, comprising:
- detecting a plurality of training sequences received via a channel by detecting an increase in energy level using a plurality of samples;
- averaging the detected plurality of detected training sequences to provide an averaged training sequence;
- circularly convolving the averaged training sequence with the transmitted training sequence to provide the estimated channel impulse response that includes a circular shift;
- and
- determining a frame delay based upon the circular shift.
A method of generating TEQ and FEQ coefficients in a DMT system, the system comprising:
- detecting a plurality of sequences received through a channel by detecting a change in energy comprises measuring energy over a plurality of samples.;
- averaging the detected plurality of sequences to provide an averaged sequence;
- determining an estimated channel impulse response for the channel based upon the averaged sequence;
- determining a frame delay based upon the estimated channel impulse response;
- calculating TEQ coefficients based upon the estimated channel impulse response and a desired channel impulse response;
- and
- calculating FEQ coefficients based upon the calculated TEQ coefficients.
A decoder suitable for generating TEQ and FEQ coefficients in a DMT system, the decoder comprising:
- an analog-to-digital converter configured to receive an analog signal through a channel and convert the analog signal into a digital signal;
- a digital signal processor operationally coupled with the analog-to-digital converter and configured to receive the digital signal;
- and
- a controller operationally coupled with the digital signal processor and configured to provide commands to the digital signal processor, wherein the commands include:
- instructions directing the digital signal processor to detect a change in energy level of the digital signal, wherein the change in energy level identifies the start of a plurality of received training sequences;
- instructions directing the digital signal processor to calculate an average of the plurality of received training sequences;
- instructions directing the digital signal processor to calculate an estimated channel impulse response based upon the average of the plurality of received training sequences;
- instructions directing the digital signal processor to calculate a frame delay based upon the estimated channel impulse response;
- instructions directing the digital signal processor to calculate TEQ coefficients based upon the estimated channel impulse response and a desired channel impulse response;
- and
- instructions directing the digital signal processor to calculate FEQ coefficients based upon the TEQ coefficients, wherein the instructions directing the digital signal processor to detect the change in energy level of the digital signal comprise instructions directing the digital signal processor to measure energy levels over a plurality of samples of the digital signal.
Dependencies are inferred from the claim text.