Receiver transparent quiescent mode operation in a DSL transmission system
First Claim
1. A method for generating a signal for use in a power saving mode in a digital subscriber line transmission system comprising:
- determining a combination of constellation points representing a signal having a peak-to-average ratio within a threshold, each constellation point representing a symbol transmitting during a payload data carrying mode comprising the step of performing the peak-to-average ratio minimization method on one or more combinations of constellation points representing symbols transmitting during the payload data carrying mode, wherein the peak-to-average ratio minimization method is an optimum subset rotation method comprising the steps ofdividing selected constellation points from candidate sets for each bin used during the payload data carrying mode into a number of subsets;
generating a time-domain signal for each subset from the selected constellation points for each subset;
adjusting a phase of each of the time-domain signals for each subset;
combining the time domain signals for each subset into a resulting signal; and
determining whether the resulting signal satisfies the peak-to-average ratio threshold; and
determining a set of input bits corresponding to each of the constellation points in the combination.
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Abstract
Operation of a digital subscriber line system in a power saving quiescent mode is described. A quiescent mode (Q-mode) is entered into from a steady-state or normal operation mode in which payload data is transmitted when criteria indicates that the transmitter has stopped transmitting payload data for a certain time period but that the current transmission session has not ended. A Q-mode signal is generated that uses constellation points that are used in the payload carrying state. The peak-to-average ratio (PAR) of the signal is also minimized by a PAR minimization method to find a combination of these constellation points satisfying a PAR threshold.
36 Citations
8 Claims
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1. A method for generating a signal for use in a power saving mode in a digital subscriber line transmission system comprising:
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determining a combination of constellation points representing a signal having a peak-to-average ratio within a threshold, each constellation point representing a symbol transmitting during a payload data carrying mode comprising the step of performing the peak-to-average ratio minimization method on one or more combinations of constellation points representing symbols transmitting during the payload data carrying mode, wherein the peak-to-average ratio minimization method is an optimum subset rotation method comprising the steps of dividing selected constellation points from candidate sets for each bin used during the payload data carrying mode into a number of subsets; generating a time-domain signal for each subset from the selected constellation points for each subset; adjusting a phase of each of the time-domain signals for each subset; combining the time domain signals for each subset into a resulting signal; and determining whether the resulting signal satisfies the peak-to-average ratio threshold; and determining a set of input bits corresponding to each of the constellation points in the combination. - View Dependent Claims (2)
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3. A method for generating a signal for use in a power saving mode in a digital subscriber line transmission system comprising:
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determining a combination of constellation points representing a signal having a peak-to-average ratio within a threshold, each constellation point representing a symbol transmitting during a payload data carrying mode comprising the step of performing the peak-to-average ratio minimization method on one or more combinations of constellation points representing symbols transmitting during the payload data carrying mode, wherein the peak-to-average ratio minimization method is an optimum subset rotation method that uses sign-inversion of intermediate results and a two-stage inverse fast-fourier transform having the steps of arranging the selected constellation points from each of the candidate sets of N bins used during the payload data carrying mode as a matrix of N2 columns and N1 rows; executing a N2-point inverse fast-Fourier transform (IFFT) on N2 inputs from a row in the matrix, and outputting N2 intermediate results to a row in an intermediate array; executing other N2-point IFFT transforms on other rows of N2 inputs and outputting N2 intermediate results from each IFFT to other rows in the intermediate array until all N1 have been transformed; executing a N1-point IFFT transform on N1 intermediate results from a column in the intermediate array, and outputting N1 time-domain outputs to a column in an output array; executing other N1-point IFFT transforms on other columns of N1 inputs from the intermediate array and outputting N1 time-domain outputs from each IFFT to other columns in the output array until all N2 columns in the intermediate array have been transformed; and determining whether the time-domain outputs satisfy a peak threshold; and determining a set of input bits corresponding to each of the constellation points in the combination. - View Dependent Claims (4)
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5. A method for generating a signal for use in a power saving mode in a digital subscriber line transmission system comprising:
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determining a combination of constellation points representing a signal having a peak-to-average ratio within a threshold, each constellation point representing a symbol transmitting during a payload data carrying mode comprising the step of performing the peak-to-average ratio minimization method on one or more combinations of constellation points representing symbols transmitting during the payload data carrying mode, wherein the peak-to-average ratio minimization method is a sequential quadrant optimization method using a bin-by-bin approach having the steps of; selecting a combination of candidate constellation points, each point being for a respective bin used during the payload data carrying mode; determining a phase of a constellation point in the combination for a first bin from a set of phases for this point resulting in a minimum peak-to-average ratio of a time-domain signal generated from the combination using this phase of the constellation point for the first bin; selecting the constellation point with the phase for the first bin; and determining whether the generated time-domain signal satisfies a peak-to-average ratio threshold; and determining a set of input bits corresponding to each of the constellation points in the combination. - View Dependent Claims (6)
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7. A method for generating a signal for use in a power saving mode in a digital subscriber line transmission system comprising:
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determining a combination of constellation points representing a signal having a peak-to-average ratio within a threshold, each constellation point representing a symbol transmitting during a payload data carrying mode comprising the step of performing the peak-to-average ratio minimization method on one or more combinations of constellation points representing symbols transmitting during the payload data carrying mode, wherein the peak-to-average ratio minimization method is a sequential quadrant optimization method using a set-by-set approach having the steps of; dividing a set of bins used during the payload data carrying mode into a number of subsets, each subset including a combination of candidate constellation points, each point being for a respective bin in the subset; determining a phase multiplier of the first subset of constellation points resulting in a minimum peak-to-average ratio of a time-domain signal generated from the combinations of all the subsets using this phase multiplier for the first subset; selecting the first subset with this phase multiplier as the combination for the first subset; and determining whether the generated time-domain signal satisfies a peak-to-average ratio threshold; and determining a set of input bits corresponding to each of the constellation points in the combination. - View Dependent Claims (8)
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Specification