DSL Transmitter Power Reduction via Tone Segmentation
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Solution Overview
Problem
DSL technologies face network instability due to increased crosstalk interference when transitioning from low power mode to normal operation, as neighboring lines adjust their operations based on reduced crosstalk levels, leading to instability upon increased power spectrum density.
Innovation Solution
Implementing a transmitter that uses a combination of low power mode (LPM) tones and non-LPM tones, where LPM tones maintain normal power spectrum density and non-LPM tones are transmitted at reduced levels, with SNR values detected and interpolated to ensure stable operation, and initial training signals are used to measure crosstalk changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the DSL transceiver operates in L2 state to reduce power consumption by reducing transmitted signal level, then power consumption is reduced, but network stability deteriorates due to crosstalk interference changes when returning to L0 state
Solution Approach 1:
The patent segments the DMT tones into two distinct groups: LPM tones transmitted at normal power levels and non-LPM tones transmitted at reduced power levels. This segmentation allows the system to achieve power reduction while maintaining stability, as the LPM tones continue to provide sufficient signal for stable operation and enable neighboring lines to adapt to crosstalk changes without causing network instability when transitioning between power states
Solution Approach 2:
The patent applies local quality by transmitting different power levels for different tone groups within the same signal. Specifically, LPM tones maintain normal PSD while non-LPM tones use reduced PSD, creating localized quality differences that achieve both power reduction and network stability. This selective power allocation allows certain frequency components to maintain stability-function while others contribute to power reduction
2Loss of energy
If the transmission PSD is reduced in L2 state, then the power consumption of the line driver is reduced, but crosstalk interference to neighboring lines increases when returning to L0 state
Solution Approach 1:
The patent segments the transmitted signal into LPM tones and non-LPM tones with different power levels. The LPM tones are transmitted at normal PSD to maintain stable operation and provide consistent crosstalk levels that neighboring lines can adapt to, while non-LPM tones are transmitted at reduced PSD to achieve power savings. This segmentation resolves the contradiction by ensuring that power reduction does not cause excessive crosstalk interference upon state transitions
Solution Approach 2:
The patent changes the PSD parameter selectively for different tone groups. LPM tones maintain normal PSD while non-LPM tones use reduced PSD, creating a hybrid transmission mode. This parameter change approach allows the system to achieve power reduction through non-LPM tones while LPM tones continue to provide stable crosstalk levels that prevent harmful interference when transitioning between power states
Data Source
AI summary
An apparatus comprising a transmitter configured to transmit a low power mode Discrete Multi-Tone (DMT) signal using a plurality of DMT tones, wherein at least some of the DMT tones comprise a low power mode (LPM) tone that carries data at a normal PSD level and a non-LPM tone that is transmitted at a reduced PSD level. Also disclosed is a network component comprising at least one processor configured to implement a method comprising detecting a plurality of signal to noise ratio (SNR) values for a plurality of LPM tone signals and a plurality of non-LPM tone signals, and handling crosstalk interference between lines using the detected SNR values.