Fast Modem Reconfiguration via SNR Estimation
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Solution Overview
Problem
DSL modems using discrete multitone (DMT) modulations, such as ADSL2 and VDSL2, face challenges with sudden noise variations leading to SNR degradation, errors, and inefficient reinitialization processes, which can result in broken links and prolonged downtime.
Innovation Solution
A method for fast reconfiguration of modems that allows for rapid adjustment of parameters by estimating SNR and exchanging new bit-loading and framing parameters, enabling quick recovery from noise variations without full reinitialization, utilizing synchronization sequences and specific DMT symbol exchanges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full reinitialization is performed to recover from noise variations, then link reliability is improved, but reconfiguration time increases
Solution Approach 1:
The reinitialization process is segmented into two distinct types: full reinitialization for complete link recovery and fast reconfiguration for minor adjustments. This segmentation allows the system to apply the appropriate level of reconfiguration based on the severity of noise variations, avoiding unnecessary full reinitializations and reducing reconfiguration time while maintaining link reliability.
Solution Approach 2:
The patent implements parameter changes by modifying the reconfiguration process to skip certain initialization steps and use pre-established parameters. Fast reconfiguration changes key parameters such as skipping handshake phases and using previously trained equalizer values, enabling rapid adaptation to noise variations without performing complete reinitialization, thus reducing time loss while maintaining reliability.
2Productivity
If fast reconfiguration is implemented to reduce reconfiguration time, then productivity is improved, but measurement precision of SNR and parameter exchange may be compromised
Solution Approach 1:
The system performs preliminary actions by pre-training equalizers and pre-establishing parameter sets during normal operation. When fast reconfiguration is needed, these pre-computed values are reused, eliminating the need for time-consuming real-time measurements while maintaining sufficient precision for accurate SNR assessment and parameter selection, thus improving productivity without sacrificing measurement accuracy.
Solution Approach 2:
Fast reconfiguration uses copying of previously measured SNR values and trained parameter sets instead of performing new measurements. The system copies effective parameters from historical data and applies them to current conditions, enabling rapid reconfiguration while maintaining measurement precision through the use of validated historical parameters that have proven effective in similar noise conditions.
3Device complexity
If handshaking and full initialization are performed during reconfiguration, then device complexity is reduced, but reconfiguration duration increases
Solution Approach 1:
The patent extracts and removes unnecessary steps from the standard initialization sequence during fast reconfiguration. Specifically, the handshake phase is extracted and omitted, and only essential parameter exchanges are performed. This extraction simplifies the reconfiguration process, reducing both device complexity and reconfiguration duration while maintaining sufficient system state synchronization.
Solution Approach 2:
The system applies partial action by performing only the necessary reconfiguration steps required for minor adjustments rather than complete reinitialization. Fast reconfiguration executes partial initialization procedures, skipping redundant steps such as full handshake protocols and comprehensive parameter validation, thereby reducing reconfiguration duration and complexity while maintaining adequate system functionality.
Data Source
AI summary
Methods, systems, and computer program products for reconfiguring a modem. In an embodiment, fast reconfiguration of a modem occurs when a first modem determines there is a need for fast reconfiguration. The first modem signals its transition from showtime to fast reconfiguration. The first modem waits for acknowledgement from a second modem before transitioning to showtime. Once transitioned from showtime, the first modem estimates a signal to noise ratio and then exchanges parameters with the second modem. The first and second modems then transition to showtime.