Vector Transmission FEXT Coefficient Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vector transmission systems, such as VDSL, FEXT (far-end crosscoupling) interference reduces data throughput due to increased line coupling at higher bandwidths, especially in shorter line lengths, as transceiver units at different subscriber locations lack information to compensate for crosstalk.
Innovation Solution
The system employs precompensation techniques by transmitting training signals to determine FEXT coupling coefficients, allowing for signal modification before transmission to mitigate crosstalk effects, using discrete multitone transmission (DMT) and frequency-time conversion to calculate and apply corrections independently for each subcarrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency bandwidth is increased to provide higher throughput data transmission, then data throughput is improved, but FEXT crosscoupling increases and reduces data throughput
Solution Approach 1:
The system performs preliminary action by transmitting training signals before actual data transmission to determine FEXT coupling coefficients. These coefficients are calculated in advance and stored for use during data transmission, allowing the system to pre-compensate for FEXT interference and maintain high throughput at increased bandwidths
Solution Approach 2:
The system changes parameters by dividing the frequency bandwidth into multiple non-overlapping subcarriers and determining separate FEXT coupling coefficients for each subcarrier. This parameter transformation allows independent compensation at different frequency levels, enabling high overall throughput while managing FEXT interference across the bandwidth
2Speed
If line length is decreased to improve transmission speed, then transmission speed is improved, but FEXT crosscoupling increases due to lower line length
Solution Approach 1:
The system performs preliminary action by transmitting training signals before actual data transmission to determine FEXT coupling coefficients. These coefficients are calculated in advance and stored for use during data transmission, allowing the system to pre-compensate for FEXT interference and maintain high throughput at increased bandwidths
Solution Approach 2:
The system changes parameters by dividing the frequency bandwidth into multiple non-overlapping subcarriers and determining separate FEXT coupling coefficients for each subcarrier. This parameter transformation allows independent compensation at different frequency levels, enabling high overall throughput while managing FEXT interference across the bandwidth
3Measurement precision
If frequency bandwidth is divided into multiple subcarriers for independent compensation, then FEXT compensation precision is improved, but system complexity increases
Solution Approach 1:
The system applies segmentation by dividing the frequency bandwidth into multiple non-overlapping subcarriers and determining separate FEXT coupling coefficients for each subcarrier. This segmentation allows independent compensation at each frequency level, improving overall FEXT compensation precision while managing complexity through modular processing
Solution Approach 2:
The system applies universality by using the same training signal transmission and coefficient determination procedure for all subcarriers. This multi-functional approach allows the same methodology to be applied across different frequency levels, improving compensation precision without proportionally increasing system complexity
Data Source
AI summary
Embodiments related to determining of coupling coefficients in a Vector transmission system are described and depicted.