Node Port Signal Attenuation for Upstream Ingress Isolation
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Solution Overview
Problem
Cable television systems suffer from upstream ingress noise interference, particularly from high-power grow lights, which overwhelm regular signals and distort or saturate the signal path, affecting multiple homes in an upstream service group.
Innovation Solution
A CCAP platform with a Remote PHY node dynamically adjusts node port assignments and attenuates signals to mitigate ingress noise, using RF matrices and attenuation techniques to segregate and isolate noisy ports, optimizing upstream and downstream traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-power grow lights are operated inside customers' homes, then illumination intensity is improved, but ingress noise interference increases and drowns out regular upstream signals
Solution Approach 1:
The system segments upstream service groups by monitoring ingress noise levels on individual upstream channels. When grow lights cause excessive ingress on a specific channel, the system identifies and segregates affected cable modems into separate service groups, isolating the noise source from other customers. This segmentation allows the illumination function to continue while protecting the overall upstream communication from being drowned out.
Solution Approach 2:
The system continuously monitors ingress noise levels on upstream channels and uses this feedback to dynamically adjust service group assignments. When grow lights are operated, the increased ingress noise is detected, triggering automatic reassignment of affected modems to different service groups. This closed-loop feedback mechanism allows the system to adapt to changing illumination conditions while maintaining signal integrity.
2Productivity
If multiple homes are connected to a single upstream receiver, then productivity is improved, but ingress noise from any one home interferes with reception from all homes in the service group
Solution Approach 1:
The system dynamically segments the upstream service group into smaller sub-groups based on real-time ingress noise measurements. When a particular home generates excessive ingress noise (e.g., from grow lights), affected modems are automatically reassigned to different upstream service groups with separate receivers. This maintains high productivity by keeping most modems grouped together while isolating noise sources to minimize their impact on overall system performance.
Solution Approach 2:
The service group configuration is made dynamic rather than static. The system continuously monitors ingress levels and automatically reassigns modems between service groups in response to changing conditions. This dynamic adjustment allows the system to maintain optimal group sizes for productivity while adaptively isolating noise sources, balancing both objectives under varying operational conditions.
3Reliability
If ingress noise is attenuated to prevent distortion and saturation, then reliability is improved, but signal strength from legitimate sources is reduced
Solution Approach 1:
Instead of applying uniform attenuation across all upstream signals, the system applies selective attenuation only to signals from identified ingress sources. By pinpointing specific cable modems or channels generating excessive noise and applying attenuation only to those local sources, the system maintains high reliability by preventing distortion while preserving the full signal strength of legitimate transmissions from other modems.
Solution Approach 2:
The system extracts and isolates the harmful ingress noise component from the overall upstream signal. By identifying specific modems or channels as noise sources and separating their signal paths through dynamic service group reassignment and selective attenuation, the system removes only the harmful portion while leaving legitimate signals untouched, thus maintaining both reliability and signal strength.
Data Source
AI summary
Processing a signal originating from a node port experiencing ingress. A node that provides service to a plurality of cable modems will generally have a plurality of node ports. The node may be a Remote PHY Node or a Remote MACPHY node (RMN) for example. A detection is made that a particular node port of the node is experiencing ingress. In response, an upstream signal originating from the particular node port is analyzed to dynamically determine an amount to attenuate the upstream signal. The upstream signal is attenuated the dynamically determined amount prior to the signal being processed at an active device upstream from the particular node port experiencing the ingress. Distortion and/or saturation of the signal at the active device is advantageously prevented.