RF Interference Cancellation in DOCSIS Networks
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Solution Overview
Problem
DOCSIS networks face interference issues due to overlapping RF bands with LTE wireless broadband technology, leading to degraded performance, as retail-grade coaxial cables and connectors provide insufficient shielding against LTE signals from nearby devices.
Innovation Solution
Implementing a noise reduction device with RF interference cancellation mechanisms, integrated into DOCSIS network equipment or as a standalone unit, which uses signal-to-noise ratio monitoring, signal reconstruction, and subtraction to cancel out LTE interference, adjusting amplitude, phase, and delay of reference signals to minimize interference impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If retail-grade coaxial cables and connectors are used in DOCSIS networks, then ease of manufacture and deployment is improved, but shielding effectiveness against LTE interference deteriorates
Solution Approach 1:
The patent introduces an intermediary device (interference cancellation device or adapter) that is inserted between the coaxial cable and the DOCSIS equipment. This intermediary captures the interference signal separately and subtracts it from the combined signal, thereby protecting the DOCSIS network from LTE interference without requiring changes to the retail-grade coaxial cables themselves.
2Object-affected harmful factors
If RF interference cancellation mechanisms are implemented, then interference reduction is improved, but device complexity increases
Solution Approach 1:
The patent segments the signal processing into distinct functional modules: a signal capture stage that separates the DOCSIS signal and interference signal into different paths, a reference signal generation stage, and a subtraction stage. This segmentation allows each module to perform a specific function, simplifying the overall implementation and reducing device complexity while maintaining effective interference cancellation.
3Reliability
If signal processing operations are performed to cancel interference, then signal quality is improved, but computational requirements and processing time increase
Solution Approach 1:
The patent performs preliminary actions by capturing and storing reference signals from the interference source before the actual signal processing occurs. These reference signals are pre-processed to extract characteristics such as amplitude, phase, and frequency. When interference cancellation is needed, the system only needs to perform a simple subtraction operation using the pre-computed reference signals, significantly reducing real-time computational requirements and processing time.
Data Source
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AI summary
An apparatus comprising a first radio frequency (RF) frontend interface configured to receive a reference signal via a first signal path and a second RF frontend interface configured to receive an interference signal via a second signal path. The apparatus further comprises a first signal adjustment chain coupled to the first RF frontend interface and configured to reconstruct a first portion of the interference signal by adjusting a first signal property of a first reference signal portion of the reference signal, and a second signal adjustment chain coupled to the first RF frontend interface and configured to reconstruct a second portion of the interference signal by adjusting a second signal property of a second reference signal portion of the reference signal, wherein the reference signal and the interference signal are associated with a same source signal.