Power allocation scheme for DMT-based modems employing simplex transmission
AssigneeAT&T Corp.
InventorsRobert Raymond Miller, II, Ranjan V. Sonalkar
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Abstract
The present invention provides a method, apparatus and computer readable medium for allocation of an available power to Discrete Multi-Tone (DMT) frequency tones in a DMT-based Digital Subscriber Line (DSL) modem. In one embodiment, the method includes the steps of: initializing the DMT-based DSL modem by calculating aggregate values of channel attenuation, noise power, and power mask; pre-filtering to flag noisy bins that are unable to support a minimum number of bits with the maximum power available for transmission in a bin; and using a repeated-bisection splitting scheme to allocate the available power substantially optimally among a plurality of bands for DMT frequency tones.
Claims6
An apparatus for allocating an available amount of power to a plurality of Discrete Multi-Tone (DMT) frequency tones, each tone in said plurality of tones corresponding to a bin of predetermined bandwidth in a plurality of bins of predetermined bandwidth, said apparatus comprising:
- a pre-filtering unit configured to identify at least a first bin of predetermined bandwidth in said plurality of bins of predetermined bandwidth that is unable to receive a predetermined minimum number of bits using a predetermined portion of said available amount of power;
- and
- a repeated-bisection power splitting and allocation unit configured to allocate said available amount of power to all bins in said plurality of bins except said at least a first bin of predetermined bandwidth,
- wherein said pre-filtering unit comprises:
- means for calculating a first number of bits that can be received in said at least a first bin of predetermined bandwidth with less than a desired bit error rate;
- and
- means for comparing said first number of bits to said predetermined minimum number of bits.
A computer readable medium encoded with computer executable instructions which, when executed by a processor, define steps for allocating an available amount of power to a plurality of Discrete Multi-Tone (DMT) frequency tones, each tone in said plurality of tones corresponding to a bin of predetermined bandwidth in a plurality of bins of predetermined bandwidth, said steps comprising:
- identifying at least a first bin of predetermined bandwidth in said plurality of bins of predetermined bandwidth that is unable to receive a predetermined minimum number of bits using a portion of said available amount of power;
- and
- allocating said available amount of power to all bins in said plurality of bins except said at least a first bin of predetermined bandwidth,
- wherein said step of identifying comprises:
- calculating a first number of bits that can be received in said at least a first bin of predetermined bandwidth with less than a desired bit error rate;
- and
- comparing said first number of bits to said predetermined minimum number of bits.
Dependencies are inferred from the claim text.