Adaptive Tilt Compensation for Upstream Channel Power Optimization
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Solution Overview
Problem
High-speed data networks face inefficiencies in power utilization due to varying signal strengths across different frequency bands and cable modem locations, leading to sub-optimal power usage in upstream communications.
Innovation Solution
Adaptive upstream channel tilt compensation is achieved through pre-compensation techniques, including power filtering/amplification and bit loading, which adjust transmit power and bit allocation based on signal strength versus frequency profiles to ensure consistent signal-to-noise ratios across the frequency spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmit power is increased to maintain signal strength across all frequency bands, then signal strength consistency is improved, but power utilization efficiency deteriorates
Solution Approach 1:
The patent applies local quality by adjusting transmit power specifically for frequency bands that exhibit tilt (uneven signal strength distribution) rather than uniformly increasing power across all bands. The system identifies which frequency bands require compensation and applies power adjustment only to those specific bands, making the power increase localized rather than global, thus improving signal consistency while minimizing overall power consumption.
Solution Approach 2:
The patent changes the power parameter dynamically based on measured signal strength versus frequency profiles. When tilt is detected in specific frequency bands, the system adjusts the transmit power parameter for those bands. This parameter change is adaptive and conditional, allowing the system to maintain signal consistency only when and where needed, rather than maintaining constant high power across all conditions.
2Device complexity
If uniform power allocation is used across all frequency bands, then device complexity is reduced, but signal-to-noise ratio consistency deteriorates
Solution Approach 1:
The patent implements feedback by measuring the signal strength versus frequency profile at the headend and using this information to control transmit power settings at cable modems. The system continuously monitors SNR consistency across frequency bands and adjusts power allocation based on this feedback. This closed-loop control ensures SNR consistency is maintained while avoiding unnecessarily complex pre-planned power allocation schemes.
Data Source
AI summary
Embodiments provide solutions to reduce power utilization (either at individual cable modems or in the overall network) in future cable networks. Particularly, embodiments seek to reduce power utilization at individual cable modems and in the overall network, by pre-compensating upstream transmissions according to feedback channel characteristics received from the headend. According to embodiments, pre-compensation is performed using power filtering/amplification and/or bit loading. Pre-compensation can be performed individually per cable modem. Further, pre-compensation can be performed over the entire upstream frequency spectrum and/or over particular sub-hands of the frequency spectrum as appropriate for each cable modem.