Digital Pre-Distortion for Efficient HFC Network Amplifiers
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Solution Overview
Problem
Cable network operators face high electrical power consumption costs due to inefficient amplifiers in Hybrid Fiber Coaxial (HFC) networks, which is exacerbated by increasing bandwidth demands, leading to significant power expenditure without proportional increases in throughput.
Innovation Solution
The implementation of a high power efficient amplifier system utilizing digital pre-distortion (DPD) and machine learning to compensate for amplifier nonlinearity and channel effects, by synchronizing input and output signals to remove distortions and optimize DPD coefficients, thereby maintaining signal linearity and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional amplifiers are used to boost signal power in HFC networks, then signal transmission is enabled, but power consumption increases significantly without proportional increase in throughput
Solution Approach 1:
The system applies digital pre-distortion to the input signal before amplification to compensate for anticipated non-linear distortions. By pre-processing the signal with inverse distortion characteristics, the amplifier operates more efficiently and produces less distortion, reducing the need for re-transmission and improving overall power efficiency
Solution Approach 2:
The system extracts a portion of the amplified output signal and feeds it back through an ADC to a distortion compensator. This feedback loop enables real-time measurement and compensation of non-linear distortions, allowing the system to optimize amplifier performance and reduce power consumption by operating at higher efficiency points
2Productivity
If amplifier power is increased to meet growing bandwidth demands, then throughput capacity improves, but power consumption increases disproportionately
Solution Approach 1:
The system dynamically adjusts amplifier operating parameters including gain, compression point, and pre-distortion coefficients based on real-time signal conditions and measured distortion characteristics. This enables the amplifier to operate at optimal efficiency points across varying bandwidth demands, improving throughput without proportional power consumption increases
3Manufacturing precision
If digital pre-distortion is applied to compensate for amplifier nonlinearity, then signal linearity improves, but system complexity increases
Solution Approach 1:
The system replaces complex analog linearization circuits with digital signal processing techniques. By implementing pre-distortion and distortion compensation in the digital domain using algorithms rather than complex analog components, the system achieves high signal linearity while reducing hardware complexity and cost
Data Source
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AI summary
An example method for facilitating a high power efficient amplifier through digital pre-distortion (DPD) in cable network environments is provided and includes receiving a first signal and a second signal at a DPD coefficient finder in an amplifier module, the second signal including transformations of the first signal from distortions due to channel effects and amplifier nonlinearity, synchronizing the first signal and the second signal, thereby removing the channel effects, computing a first vector representing an inverse of the nonlinearity of the amplifier, computing a second vector representing an inverse of some of the channel effects and providing DPD coefficients to a DPD actuator in the amplifier module, the DPD coefficients including the first vector and the second vector, the DPD actuator predistorting an input signal to the amplifier module with the DPD coefficients, such that an output signal from the amplifier module retains linearity relative to the input signal.