Cable Modem Leakage Detection via Upstream Signal Inversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The transition to a high-split architecture in cable networks, which moves the upstream spectrum to include the FAA band, renders existing leakage detection methods ineffective, as they rely on frequencies that are no longer available in the downstream portion of the spectrum.
Innovation Solution
Cable modems are configured to generate leakage detection signals compatible with upstream traffic using Orthogonal Frequency-Division Multiple Access (OFDMA) and OFDM Upstream Data Profile (OUDP) bursts, allowing for precise leakage location identification through time-sequenced signaling controlled by the Cable Modem Termination System (CMTS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the upstream spectrum is expanded to include the FAA band (high-split architecture), then upstream bandwidth is increased, but the ability to monitor and measure leakage in the FAA band is lost
Solution Approach 1:
Instead of inserting a downstream signal that travels upstream (the traditional method), the patent inverts the approach by having cable modems generate upstream signals that travel downstream through the cable infrastructure. This allows leakage detection in the FAA band while maintaining high-split architecture with expanded upstream bandwidth.
Solution Approach 2:
The patent uses cable modems as intermediary devices that generate special-purpose upstream signals containing leakage detection information. These signals serve as mediators between the expanded upstream spectrum and the leakage detection function, enabling both high-split operation and leakage monitoring.
2Measurement precision
If a special leakage detection signal is inserted into the downstream cable TV channel lineup, then leakage can be detected, but the signal cannot traverse the network when the detection frequency resides in the upstream portion of the spectrum
Solution Approach 1:
The patent reverses the traditional signal direction by having cable modems transmit upstream signals instead of the headend inserting downstream signals. This inversion allows the detection signal to properly traverse the network infrastructure even when the detection frequency (138 MHz) resides in the upstream portion of the spectrum under high-split architecture.
Solution Approach 2:
The patent makes cable modems multi-functional by having them serve both their normal data communication function and the additional function of generating leakage detection signals. This universality allows the same upstream infrastructure to support both expanded bandwidth and leakage detection without requiring separate dedicated signal paths.
3Difficulty of detecting and measuring
If new signal-generation hardware is added to the network to enable leakage detection, then leakage detection capability is restored, but network complexity and cost increase
Solution Approach 1:
The patent implements self-service by having existing cable modems generate their own leakage detection signals without requiring external signal-generation hardware. Each cable modem uses its own resources and capabilities to produce the special-purpose upstream signals, eliminating the need for additional network infrastructure.
Solution Approach 2:
The patent leverages the existing multi-functionality of cable modems by adding leakage signal generation to their capabilities. Rather than adding dedicated hardware, the solution uses the universal nature of modern cable modems to perform both data communication and leakage detection functions, reducing network complexity.
Data Source
AI summary
A method of using customer premise cable modem equipment to generate a signal that can be used for leakage detection. Various signal types are described which are usable for the purposes of leakage detection.