Off-Diagonal MIMO Precoder for xDSL Self-FEXT Cancellation
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Solution Overview
Problem
Current xDSL communication systems face challenges with crosstalk, particularly self-FEXT, which affects performance and requires costly design and resource-intensive solutions, lacking efficient means for precoder updates and user additions.
Innovation Solution
The implementation of an off-diagonal multiple input multiple output (MIMO) precoder (ODMP) that learns channel characteristics, converges to an optimum configuration using a least means square (LMS) adaptive algorithm, and minimizes transmit power, allowing for efficient self-FEXT cancellation and incremental user management without computationally intensive matrix inversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional crosstalk cancellation methods are used, then crosstalk performance is improved, but system complexity and computational resources increase significantly
Solution Approach 1:
The patent segments the full MIMO precoder into two distinct components: a diagonal precoder for power control and a separate off-diagonal precoder specifically for self-FEXT cancellation. This segmentation allows each component to be optimized independently, reducing overall system complexity while maintaining effective crosstalk cancellation performance.
Solution Approach 2:
The patent extracts and isolates the self-FEXT cancellation function into a dedicated off-diagonal precoder component, separating it from the overall precoding operation. This extraction enables focused optimization of the crosstalk cancellation mechanism without affecting other system functions, thereby reducing computational burden.
2Object-affected harmful factors
If conventional MIMO precoding is used, then self-FEXT cancellation is achieved, but computational resources and processing time increase
Solution Approach 1:
The patent implements a dynamic adaptation mechanism where the off-diagonal precoder is initialized and then continuously refined using LMS algorithms based on feedback from user equipment. This dynamic approach allows the system to converge to optimal performance efficiently, reducing processing time compared to static conventional methods.
Solution Approach 2:
The patent incorporates a feedback mechanism where user equipment transmits error data back to the network device, which uses this feedback to iteratively refine the off-diagonal precoder through LMS algorithms. This feedback-driven approach enables faster convergence to optimal self-FEXT cancellation with reduced computational overhead.
3Object-affected harmful factors
If traditional precoder designs are used, then crosstalk precompensation is provided, but bandwidth efficiency and resource utilization decrease
Solution Approach 1:
The patent applies partial action by implementing only the off-diagonal portion of the full MIMO precoder, focusing specifically on self-FEXT cancellation while leaving diagonal power control to separate mechanisms. This partial implementation achieves effective crosstalk compensation without the computational overhead of complete MIMO precoding, thereby improving bandwidth efficiency.
Data Source
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AI summary
The system and method for off-diagonal MIMO precoders for generating precoded signals to increasing system performance for plurality of users in an xDSL system (130), comprising, an initialization module (170) configured to learn characteristics of channels located within the xDSL system associated with the plurality of users to derive an initial ODMP; a tracking module (172) configured to converge towards an optimum OPDM from the initial ODMP to reduce downstream self-induced far end crosstalk (self-FEXT) by executing a least means square (LMS) adaptive algorithm, wherein the tracking.