Virtual Delta-Sigma Digitization for Nonlinear Noise-Tolerant HFC Links
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Solution Overview
Problem
Conventional hybrid fiber-coaxial (HFC) networks face limitations in achieving high data rates due to link loss and nonlinear noise, particularly with high-order modulation formats, which are not adequately addressed by existing analog optics technology, making it difficult to support increasing data demands without expensive infrastructure replacements.
Innovation Solution
The implementation of a digital optical network using delta-sigma modulation and demodulation techniques, which convert analog signals into digitized bit streams for transmission over digital optical links, effectively separating noise from the signal and enabling longer distances and higher modulation orders without requiring significant hardware modifications to existing infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-order modulation formats are used to increase data rates, then spectral efficiency is improved, but tolerance to nonlinear noise deteriorates
Solution Approach 1:
The patent replaces analog optical transmission with digital optical transmission. By converting analog signals to digital signals using ADC at the headend and DAC at the network unit, the system eliminates the accumulation of nonlinear noise that plagues analog systems. This substitution enables the use of high-order modulation formats (64-QAM, 256-QAM, 1024-QAM) to achieve higher data rates while maintaining reliability through digital signal processing and error correction capabilities.
2Device complexity
If analog optics technology is used to maintain existing infrastructure, then device complexity is reduced, but transmission distance and data rate are limited
Solution Approach 1:
The patent fundamentally changes the transmission medium parameter from analog to digital. By implementing digital optical transmission with ADC/DAC conversion, the system can support much higher data rates (up to 10 Gbps or more) compared to analog systems, while the existing fiber optic infrastructure remains compatible. The digital architecture allows for flexible configuration and scalable deployment.
3Productivity
If digital optical transmission is implemented to increase data rates, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent segments the digital optical transmission system into distinct functional blocks: ADC at the headend for analog-to-digital conversion, digital signal processing for error correction and modulation, optical transmission through existing fiber infrastructure, and DAC at network units for digital-to-analog conversion. This segmentation allows each component to be optimized independently and deployed in a modular fashion, reducing overall system complexity despite the advanced capabilities.
Data Source
AI summary
A method for virtually performing delta-sigma digitization is provided. The method is performed on a series of digital samples output from a communication stack of a communication network. The method includes steps of obtaining a delta-sigma digitization sampling frequency for the output series of digital samples, calculating an oversampling ratio for the output series of digital samples, interpolating the output series of digital samples at a rate equivalent to the oversampling ratio, and quantizing the interpolated series of digital samples to plurality of discrete predetermined levels.