Semi-distributed power spectrum control for DSL crosstalk
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Solution Overview
Problem
Digital Subscriber Line (DSL) systems face limitations in maximizing data rates due to crosstalk and power spectral density (PSD) constraints, particularly in multi-user environments where higher data rates are demanded, and existing methods either consider each user independently or require centralized optimization with extensive communication and computation.
Innovation Solution
A distributed method for optimizing power spectral density in DSL systems, where each user maximizes its own data rate while accounting for crosstalk from other users, using a Lagrangian multiplier to adjust PSD constraints, allowing for local optimization with minimal central management and communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If centralized optimization is used to maximize data rates, then data rate performance is improved, but communication overhead and computational burden increase significantly
Solution Approach 1:
The patent segments the centralized optimization problem into distributed sub-problems solved by individual users. Each user independently optimizes their own power spectral density based on local channel conditions and target data rate requirements, eliminating the need for centralized computation and reducing communication overhead while maintaining optimal performance
Solution Approach 2:
Each user in the DSL system performs self-optimization of their power spectral density allocation based on local information including channel characteristics, crosstalk conditions, and target data rate requirements. This self-service approach eliminates dependency on centralized control while achieving optimal data rates
2Device complexity
If each user optimizes independently without considering other users, then computational complexity is reduced, but crosstalk interference increases and overall system performance deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where each user monitors the actual data rate achieved against their target data rate requirement. Based on this feedback, users adjust their power spectral density allocation iteratively, taking into account crosstalk from other users, thereby reducing harmful interference while maintaining computational simplicity
Data Source
AI summary
A semi-distributed method of managing the spectral power over multiple digital subscriber line communication loops (LP1, LP2) is disclosed. A central office (CO) DSL transceiver (10) and a remote terminal (RT) DSL transceiver (15) communicate with customer premises equipment (CPE) (121, 122) over separate twisted-pair wire loops (LP1, LP2) that are in sufficient physical proximity with one another as to suffer from crosstalk. A network management center (NMC) (20) initializes a price parameter, which is used by the CO (10) and RT (15) in independent maximization problems. The CO (10) derives a maximum tolerable power spectral density for the RT (15) that permits the CO (10) to reach a target data rate, and the RT (15) derives an actual power spectral density that maximizes its data rate, each using the price parameter. The NMC (20) compares the actual RT power spectral density to the tolerable RT power spectral density, and adjusts the price parameter accordingly, with the process repeating until convergence. As a result, the RT data rate is maximized to a level that still permits the CO (10) to reach its target data rate, thus maximizing the overall network data rate.