HFC Node Power Allocation Under Transmitter Distortion
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Solution Overview
Problem
Current implementations of node circuits in hybrid fiber coax (HFC) networks do not account for transmitter distortion when determining transmit power levels, leading to suboptimal data rates due to a trade-off between transmitter distortion and receiver noise, especially at higher frequencies.
Innovation Solution
A node circuit that determines an optimal transmit power based on receiver noise and a distortion model of the transmitter circuit, allocating subcarriers according to frequency and distance, and optimizing power distribution to maximize data rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmit power is increased to handle increasing traffic requirements and improve data rates, then signal transmission capability is improved, but transmitter distortion increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting transmit power levels based on frequency-dependent distortion characteristics. The system modifies the power parameter across different subcarriers according to a distortion model, allocating higher power to frequencies with lower distortion and lower power to frequencies with higher distortion, thereby optimizing the trade-off between data rate and distortion.
Solution Approach 2:
The patent implements local quality by applying different transmit power levels to different frequency subcarriers based on their individual distortion characteristics. Instead of uniform power allocation, the system tailors the power distribution to local conditions at each frequency, maximizing overall system performance while accounting for frequency-specific distortion behavior.
2Quantity of substance
If higher frequencies are used to increase capacity and handle more traffic, then network capacity is improved, but transmitter distortion becomes more significant
Solution Approach 1:
The patent changes the power parameter as a function of frequency, using the distortion model to determine optimal power levels at each frequency. This allows the system to utilize higher frequencies for increased capacity while compensating for their higher distortion characteristics through reduced power allocation, maintaining signal quality across the frequency spectrum.
Solution Approach 2:
The patent introduces dynamics by making transmit power allocation adaptive and frequency-dependent rather than static and uniform. The system continuously adjusts power distribution across frequencies based on real-time distortion model evaluations, enabling flexible optimization as traffic requirements and network conditions change.
3Ease of operation
If uniform power allocation is used across all subcarriers, then implementation is simple, but data rates are suboptimal due to not accounting for frequency-dependent distortion
Solution Approach 1:
The patent moves from uniform power allocation to frequency-dependent power allocation by changing the power parameter based on distortion characteristics at each subcarrier. This approach maintains relative implementation simplicity through automated calculation while significantly improving data rates by optimizing power distribution according to actual channel conditions.
Solution Approach 2:
The system performs self-service by automatically calculating and adjusting optimal power allocation based on its own distortion model and measured SNR values. The node circuit independently determines the optimal power distribution without requiring complex external control, achieving both improved performance and operational simplicity through self-optimization.
Data Source
AI summary
A node circuit associated with a hybrid fiber coax (HFC) network is disclosed. The node circuit includes an optimizer circuit configured to process a plurality of signal-to-noise ratio (SNR) values associated with a plurality of subcarriers, respectively, associated with a set of cable modem (CM) circuits coupled to the node circuit. In some embodiments, at least one subcarrier is allocated to the set of CM circuits for communication with the node circuit. In some embodiments, the optimizer circuit is further configured to determine an optimal transmit power of the node circuit, based on the plurality of SNR values and a transmitter distortion of a transmitter circuit associated with the node circuit. In some embodiments, the transmitter distortion defines a transmitter distortion associated with the transmitter circuit in terms of a total transmit power of the node circuit.