Method and apparatus for adaptive data allocation in a multi-carrier communication system
AssigneeVirata Limited
InventorsJames J. Stiscia, Raymond Chen
Life of this patent
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Abstract
An xDSL modem having an adaptively adjustable guard band comprising a finite number of spaced-apart frequency bins between the upstream and downstream frequencies. The guard band is adjusted by selecting one from among a plurality of filters belonging to a filter bank of the receiver circuitry. A weighted loss in data capacity is calculated when each of the candidate filters are used, and the filter which gives the lowest loss in data capacity, subject to certain criteria, is used. The adjustment is made pursuant to noise and signal characteristics measured during start or restart of an xDSL communications session.
Claims22
An xDSL modem comprising:
- receiver circuitry including a filter bank comprising a plurality of filters having a corresponding plurality of cut-off frequencies spaced apart from one another within a frequency band situated between an upstream and a downstream channel associated with said modem;
- and
- a controller configured to select at least one of said plurality of filters for use during an xDSL session.
A method of establishing a width of a guard band in a full-duplex frequency division multiplexed (FDM) communication device, the method comprising:
- measuring background noise level at a first transceiver;
- measuring local transmitter echo of said first transceiver;
- and
- selecting one from among a plurality of receiver filters, based on results of said measuring steps, wherein a cut-off frequency of said one filter establishes one end of said guard band.
An xDSL modem having at least one processor, said at least one processor having associated therewith at least one computer readable medium having computer executable software code stored thereon, said software code including:
- code to measure background noise level of a transceiver of said modem;
- code to measure local transmitter echo of said transceiver;
- code to calculate at least one metric reflective of data capacity loss from measurements of said background noise level and local transmitter echo:
- and
- code to select one from among a plurality of receiver filters of said transceiver, based on said at least one metric.
A computer readable medium having computer executable software code for an xDSL modem stored thereon, said software code including:
- code to measure background noise level of a transceiver of said modem;
- code to measure local transmitter echo of said transceiver;
- code to calculate at least one metric reflective of data capacity loss from measurements of said background noise level and local transmitter echo;
- and
- code to select one from among a plurality of receiver filters of said transceiver, based on said at least one metric reflective of data capacity loss.
Dependencies are inferred from the claim text.