Cable Modem Upstream Signals for TV Network Leakage Detection
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Solution Overview
Problem
The shift in cable TV network spectrum allocation to include the civil aircraft communications band (118-137 MHz) for upstream traffic complicates leakage detection, as traditional downstream leakage detection signals cannot be used, necessitating a new method to monitor and measure leakage in this frequency range.
Innovation Solution
Utilizing customer premise cable modems to generate upstream leakage detection signals, such as Orthogonal Frequency-Division Multiple Access (OFDMA) OUDP bursts, synchronized and time-sequenced across a defined number of cable modems, with control from a Cable Modem Termination System (CMTS) or Remote PHY device, and detected by specialized receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the split frequency is increased to expand upstream bandwidth (high-split architecture), then upstream bandwidth is improved, but the ability to monitor leakage in the FAA band using traditional downstream methods deteriorates
Solution Approach 1:
The patent inverts the traditional leakage detection approach by having cable modems transmit upstream detection signals instead of the headend transmitting downstream signals. This inversion allows leakage detection to function in the upstream spectrum where the FAA band monitoring is needed, resolving the contradiction between expanded upstream bandwidth and leakage detection capability
Solution Approach 2:
The patent introduces an intermediary approach by using existing cable modem equipment to generate and transmit detection signals through the upstream network. This intermediary use of customer premise equipment enables leakage detection without requiring new headend signal generation hardware, maintaining detection capability while supporting high-split architecture
2Measurement precision
If traditional downstream leakage detection signals are used in high-split architecture, then leakage detection can be performed, but the signals cannot traverse the network as the 138 MHz frequency now resides in the upstream portion
Solution Approach 1:
The patent inverts the signal transmission direction by having cable modems transmit upstream detection signals rather than the headend transmitting downstream signals. This inversion resolves the frequency allocation conflict in high-split architecture where traditional downstream detection frequencies now fall in the upstream band
Solution Approach 2:
The patent changes the operational parameters of cable modems to transmit specific detection signals (such as OUDP burst signals) upstream. This parameter change allows the detection function to adapt to the high-split frequency allocation while maintaining signal transmission compatibility across the network
3Device complexity
If cable modems are configured to generate leakage detection signals, then new hardware additions are avoided, but the upstream spectrum must support detection frequencies up to 684 MHz and beyond
Solution Approach 1:
The patent makes cable modems multi-functional by configuring them to both transmit data upstream and generate leakage detection signals. This universality allows existing customer premise equipment to serve dual purposes, avoiding new hardware while supporting the expanded upstream spectrum for detection frequencies up to 684 MHz and beyond
Solution Approach 2:
The patent implements self-service by having cable modems generate their own leakage detection signals rather than requiring external signal generation equipment. This self-service approach allows the network to perform its own diagnostic function using existing infrastructure, reducing hardware complexity while maintaining frequency adaptability
Data Source
AI summary
A method of using customer premises 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.