Crosstalk Coupling Vector Determination in Vectored DSL Systems
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Solution Overview
Problem
The initialization time of a joining line in a communication system, such as a vectored DSL system, is prolonged due to the need to determine crosstalk coefficients from active lines, which affects data rates and reliability.
Innovation Solution
A method involving the transmission of pilot signals across multiple lines, using a pilot matrix to obtain measurement vectors, determining a weighted vector, and identifying non-zero elements of the crosstalk coupling vector through an orthogonal matching pursuit algorithm, to reduce crosstalk interference and apply pre-coder coefficients efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pilot signals are transmitted across all lines to determine crosstalk coefficients, then measurement precision is improved, but initialization time increases
Solution Approach 1:
The patent extracts only the significant crosstalk components from the full set of possible disturber lines. By identifying and focusing on the subset of lines that contribute meaningfully to crosstalk (those with coupling coefficients above a threshold), the system achieves accurate crosstalk measurement without requiring pilot signals to be transmitted across all possible line combinations, thereby reducing initialization time while maintaining measurement precision.
Solution Approach 2:
Instead of performing complete crosstalk measurement across all possible line combinations, the patent applies partial action by measuring only the significant crosstalk components. The system transmits pilot signals only from identified disturber lines rather than all possible lines, achieving sufficient measurement precision for practical purposes while significantly reducing the time and computational resources required.
2Reliability
If crosstalk coefficients are determined for all active lines, then reliability is improved, but computation complexity increases
Solution Approach 1:
The patent extracts only the significant crosstalk components from the full set of possible disturber lines. By identifying and focusing on the subset of lines that contribute meaningfully to crosstalk (those with coupling coefficients above a threshold), the system achieves reliable data transmission without requiring computation for all possible line combinations, thereby reducing computational complexity while maintaining reliability.
3Productivity
If the number of active communication lines increases, then system capacity is improved, but crosstalk interference increases
Solution Approach 1:
The patent implements feedback by continuously monitoring crosstalk levels and dynamically identifying disturber lines based on actual measured coupling coefficients. This feedback mechanism allows the system to adapt to increasing numbers of active lines by automatically detecting which lines are generating significant crosstalk and adjusting the measurement and compensation strategies accordingly, thereby maintaining system capacity while managing crosstalk interference.
Data Source
AI summary
At least one example embodiment discloses a method of determining crosstalk for at least one first line in a communication system having a plurality of second lines. The method includes obtaining at least one pilot matrix representing a sequence of pilot signals and transmitting pilot signals across the plurality of second lines in accordance with the at least one pilot matrix. The method further includes obtaining measurement vectors for the at least one first line on a plurality of subcarriers, in response to the transmitted pilot signals, determining a weighted vector, the weighted vector being a weighted combination of the measurement vectors and determining a crosstalk coupling vector based on the determined weighted vector.