DSL Spectrum Management via Distributed Power Allocation
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Solution Overview
Problem
Current digital communication systems, particularly DSL networks, face performance degradation due to crosstalk interference from twisted copper pairs, which limits data rates and requires complex, centralized optimization methods that are not practical for real-time adaptation.
Innovation Solution
A distributed spectrum management method that assesses and optimizes power levels within each band of a digital communication system, considering predetermined maximum interference, using a centralized or distributed approach to adjust power allocation and mitigate crosstalk through iterative feedback and band preference design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized optimization methods are used to manage spectrum allocation, then network performance can be optimized, but computational complexity and implementation difficulty increase significantly
Solution Approach 1:
The patent segments the spectrum allocation problem into band-specific power control decisions. Instead of optimizing the entire spectrum simultaneously, the system divides frequency bands and applies water-filling power allocation independently to each band, reducing computational complexity while maintaining performance optimization.
Solution Approach 2:
The patent implements dynamic spectrum management where power spectral densities are adjusted iteratively based on feedback from crosstalk measurements. The system continuously adapts power allocation across different bands rather than using static allocation, enabling real-time optimization without requiring complex centralized computation.
2Productivity
If power levels are increased to overcome crosstalk interference, then data rates can be maintained, but interference to other users increases
Solution Approach 1:
The patent applies local quality by optimizing power spectral density independently for each frequency band based on local crosstalk conditions. Each band receives the minimum necessary power to achieve target data rates, avoiding excessive power transmission that would create harmful interference. The water-filling algorithm allocates power selectively to bands where it provides maximum benefit with minimum interference.
Solution Approach 2:
The patent implements feedback mechanisms where modems measure crosstalk interference and report back to the spectrum management system. Power spectral densities are then adjusted based on this feedback, creating a closed-loop control system that dynamically balances data rate requirements against interference generation.
3Ease of operation
If static spectrum allocation is used to simplify management, then implementation is easier, but adaptability to changing network conditions deteriorates
Solution Approach 1:
The patent transitions from static to dynamic spectrum management by implementing iterative water-filling algorithms that continuously adjust power spectral densities based on current network conditions. The system adapts to changing crosstalk patterns, user demands, and channel conditions while maintaining relatively simple band-specific control mechanisms.
Solution Approach 2:
The patent applies preliminary action by pre-defining frequency bands and their associated power control parameters before operation. This band structure provides a simplified framework for management, while the water-filling algorithm within each band enables dynamic adaptation to changing conditions without requiring complete reconfiguration.
Data Source
AI summary
Provided is a method of determining a spectrum management of digital communication systems having a plurality of communication lines by determination of the power levels within each band, for each user, assuming a predetermined maximum interference from other users. The spectral management center has a power allocation determinator for receiving a modelled power level and a noise weight from each user communication line and is able to determine allocated power of its respective communication line based on the optimised determined power needs of the plurality of communication lines of the digital communication systems. In one form the calculations are undertaken in the SMC. In another form the master is undertaken in the SMC while the slave is undertaken at the user's modem and the power level of an individual communication line and its interference by adjacent lines is determined at the user's modem and communicated to the spectral management center.