System and method for reducing the effects of clipping in a DMT transceiver
AssigneeGlobespanVirata, Inc.
InventorsDaniel Amrany, Lujing Cai, Weimin Liu
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Abstract
The present invention is directed to a system and method for reducing the need to perform signal clipping in a DMT transmitter. In accordance with one aspect of the invention, a method performs an inverse Fourier Transform on the input to produce a time-domain, digital value to be transmitted to a remote receiver. The method then evaluates the magnitude of the digital value to determine whether the magnitude exceeds a threshold value. Then, the method alters the input and re-performs an inverse Fourier Transform on the altered input, only if the step of evaluating the magnitude determines that the magnitude of the digital value exceeds the threshold value.
Claims9
In a discrete multi-tone (DMT) transmitter, a method for reducing the need to perform signal clipping comprising the steps of:
- providing an input;
- performing an inverse Fourier Transform on the input to produce a digital value to be transmitted;
- evaluating the magnitude of the digital value to determine whether the digital value will saturate an operative downstream component;
- and
- altering the input and re-performing an inverse Fourier Transform on the altered input if the step of evaluating the magnitude determines that the magnitude of the digital value will saturate the operative downstream component;
- wherein the step of altering the step of providing an input includes producing the input from a mapper, and the step of altering the input includes rotating a signal constellation defined by the mapper.
In a discrete multi-tone (DMT) transmitter, a method for reducing the need to perform signal clipping comprising the steps of:
- performing an inverse Fast Fourier Transform (IFFT) on an input to produce a digital value to be transmitted;
- evaluating the magnitude of the digital value to determine whether the magnitude will saturate an operative downstream component;
- and
- recursively altering the input and re-performing the IFFT until the magnitude of the digital value will not saturate an operative downstream component;
- wherein the step of recursively altering the input is consecutively executed until the magnitude of the digital value will not saturate the operative downstream component and the number of bits altered is less than a predetermined number, so that Reed Solomon decoding at a receiver may recover the signal, without having to communicate additional information bits.
In a discrete multi-tone (DMT) transmitter, a method for reducing the need to perform signal clipping comprising the steps of:
- performing an inverse Fast Fourier Transform (IFFT) on an input to produce a digital value to be transmitted;
- evaluating the magnitude of the digital value to determine whether the magnitude will saturate an operative downstream component;
- and
- recursively altering the input and re-performing the IFFT until the magnitude of the digital value will not saturate an operative downstream component;
- and
- communicating additional information bits to a remote receiver, wherein the additional information bits inform the remote receiver as to the manner in which the input was altered, so that the original input may be recovered.
Dependencies are inferred from the claim text.