FDX Node Echo Scrambling via Phase Distribution
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Solution Overview
Problem
In Hybrid Fiber-Coaxial (HFC) networks, Full Duplex (FDX) nodes experience increased interference due to coherent combining of echoes from multiple ports, leading to a 12 dB increase in interference to desired signal ratio compared to single port operation, which affects bi-directional full duplex traffic.
Innovation Solution
The use of power splitter/combiner hybrids in FDX nodes scrambles the phases of echoes from multiple ports over 360 degrees, preventing coherent combining and allowing echoes to cancel each other out, by employing a combination of 0 degree, 90 degree, and 180 degree power splitter/combiner hybrids in a way that distributes phases uniformly across 360 degrees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple ports are used in FDX node for bi-directional full duplex traffic, then network capacity and service capability are improved, but coherent combining of echoes from multiple ports causes 12 dB increase in interference to desired signal ratio
Solution Approach 1:
The patent changes the phase parameter of echoes by introducing different path lengths through power splitter/combiner hybrids. By configuring splitters and combiners with specific path length differences, the phase of echoes from different ports is shifted to distribute them uniformly over 360 degrees, transforming coherent combining into incoherent distribution and reducing interference.
Solution Approach 2:
The patent converts the harmful coherent combining effect into a beneficial incoherent distribution. By intentionally introducing phase shifts through power splitter/combiner hybrids, the system transforms the problematic echo coherence into random phase distribution, where echoes cancel each other out statistically rather than adding constructively, thereby reducing the interference to desired signal ratio.
2Object-affected harmful factors
If power splitter/combiner hybrids are used to scramble echo phases, then echo levels are reduced and signal-to-interference ratio is improved, but device complexity increases due to multiple splitter/combiner components
Solution Approach 1:
The patent segments the signal path into multiple independent segments through power splitters and combiners. Each splitter/combiner creates separate path segments with controlled length differences, allowing phase scrambling to occur through the cumulative effect of these segmented paths. This segmentation approach achieves echo reduction while maintaining modular device architecture.
Solution Approach 2:
The patent introduces a new dimension of path length variation in the signal transmission path. By configuring power splitter/combiner hybrids with different physical path lengths, the system adds a temporal/phase dimension to the signal processing, transforming the single-dimensional direct path into multi-dimensional paths that achieve phase diversity and echo cancellation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces echo levels by ensuring that echoes do not combine coherently, thereby improving the signal-to-interference ratio and enhancing the performance of bi-directional full duplex traffic in HFC networks.
Implementation Method 1
The plurality of splitters and the plurality of combiners may scramble phases of completed loops from the transmit portion transmit port to the receive portion receive port resulting from reflections from the plurality of ports
Data Source
AI summary
Reduce echo level may be provided by scrambling phases of echoes from multiple ports in a Full Duplex (FDX) node. The FDX node may comprise a transmit portion, a receive portion, and a plurality of ports. The transmit portion may comprise a transmit portion transmit port and a plurality of splitters. The receive portion may comprise a receive portion receive port and a plurality of combiners. The plurality of splitters and the plurality of combiners may scramble phases of completed loops from the transmit portion transmit port to the receive portion receive port resulting from reflections from the plurality of ports.