DSL rate adaptation
AssigneeBroadcom Corporation
InventorDavid Jones
Life of this patent
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Abstract
A method for enhancing the bit rate and/or margin at which quadrature amplitude modulation (QAM) communication is performed includes the steps of varying a spectral allocation and constellation size with which communication is performed, so as to define a combination of spectral allocation and constellation size at which the bit rate and/or margin are enhanced. The spectral allocation can be varied by varying a stop frequency thereof, while maintaining a substantially constant start frequency, so as to mitigate undesirable high frequency content of the bandwidth. Alternatively, both start and stop frequencies may be varied.
Claims33
A method for data communication over a transmission channel, comprising:
- (a) evaluating, by a communications transceiver, a channel response characteristic with respect to a constellation size and a single carrier having an adjustable center frequency of a transmission signal;
- (b) varying, by the communications transceiver, the adjustable center frequency of the transmission signal;
- (c) determining, by the communications transceiver, a maximum spectral allocation for the transmission channel for which a signal-to-noise ratio is less than a predetermined value;
- (d) re-evaluating, by the communications transceiver, the channel response characteristic with respect to the varied center frequency;
- and
- (e) determining, by the communications transceiver, an optimal constellation size and optimal center frequency responsive to at least one of an optimum bit rate and an optimum noise margin.
A method for enhancing a potential channel response characteristic of a transmission channel, comprising:
- (a) varying, by a communications transceiver, a center frequency and a constellation size of the transmission channel;
- (b) determining, by the communications transceiver, the potential channel response characteristic associated with the center frequency and the constellation size;
- and
- (c) defining, by the communications transceiver, a combination of the center frequency and the constellation size at which the potential channel response characteristic is enhanced.
A system for data communication over a transmission channel, comprising:
- means for evaluating a channel response characteristic with respect to a constellation size and a single carrier having an adjustable center frequency of a transmission signal;
- means for varying the adjustable center frequency of the transmission signal;
- means for determining a maximum spectral allocation for the transmission channel for which a signal-to-noise ratio is less than a predetermined value;
- means for re-evaluating the channel response characteristic with respect to the varied center frequency;
- and
- means for determining an optimal constellation size and an optimal center frequency responsive to at least one of an optimum bit rate and an optimum noise margin.
A system for enhancing a potential channel response characteristic of a transmission channel, comprising:
- means for varying a center frequency and a constellation size of the transmission channel;
- means for determining the potential channel response characteristic associated with the center frequency and the constellation size;
- and
- means for defining a combination of the center frequency and the constellation size at which the channel response characteristic is enhanced.
Dependencies are inferred from the claim text.