Tone Pairing for DMT Interpolation Error Mitigation
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Solution Overview
Problem
In Discrete Multi-Tone (DMT) systems, interpolation errors in crosstalk vectoring increase as tones move further from their interpolation endpoints, limiting the number of subscriber lines that can be included in a vectoring group while maintaining a desired Signal-to-Noise Ratio (SNR).
Innovation Solution
Tones with relatively large interpolation errors are paired with those having small interpolation errors to mitigate peak interpolation error, using a trellis encoder to combine data bits and append parity information for error correction, thereby reducing overall interpolation error across the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the interpolation factor is increased to enable more subscriber lines in a vectoring group, then the quantity of subscriber lines is improved, but the interpolation error increases and signal quality deteriorates
Solution Approach 1:
The patent segments the vectoring group into multiple subgroups, each with its own interpolation factor. This allows different interpolation factors to be applied to different subgroups, enabling the system to include more subscriber lines overall while maintaining lower interpolation errors within each subgroup. The segmentation resolves the contradiction by distributing the interpolation burden across multiple smaller groups rather than applying a single high interpolation factor to the entire group.
Solution Approach 2:
The patent applies different interpolation factors to different subgroups based on their specific characteristics and requirements. This local quality approach allows optimal interpolation factors to be selected for each subgroup, balancing the number of subscriber lines with interpolation error tolerance on a local basis rather than using a uniform approach across the entire vectoring group.
2Productivity
If the interpolation factor is increased to expand the vectoring group size, then the productivity of the system is improved, but the signal quality deteriorates due to increased interpolation error
Solution Approach 1:
The patent segments the vectoring group into multiple subgroups with different interpolation factors, allowing the system to achieve higher overall productivity by including more subscriber lines while maintaining signal quality through lower interpolation factors in each subgroup. This segmentation enables the system to scale productivity without sacrificing reliability.
Solution Approach 2:
The patent dynamically adjusts interpolation factors for different subgroups based on system conditions and requirements. This dynamic approach allows the system to optimize the balance between productivity and signal quality, adjusting the interpolation factor distribution to match current operational needs and maintain reliability while maximizing throughput.
Data Source
AI summary
In a vectored Discrete Multi-Tone (DMT) system that employs trellis encoding, tones of a DMT signal are paired by a trellis encoder, and parity information is shared between the paired tones. In accordance with some embodiments, the tones are paired based on an interpolation pattern that is used to calculate vectoring coefficients in an effort to mitigate interpolation error. Specifically, a tone having a vectoring coefficient with a relatively large interpolation error may be paired with a tone having a vectoring coefficient with a relatively small interpolation error thereby reducing the peak interpolation error among paired tones within the system. By reducing the peak interpolation error in the paired tones, the number of communication lines included in a vectoring group can be increased without significantly degrading signal quality.