Echo Cancellation in Coaxial Cable Modems
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Solution Overview
Problem
The full duplex operation in cable modem termination systems (CMTS) and cable modems leads to noise and echo interference due to the simultaneous sending and receiving of signals on the same path, which existing technologies have not effectively addressed, causing channel interference and reflection issues.
Innovation Solution
A communication system is configured with CMTS and cable modem echo cancellation engines that generate a 180-degree phase offset of the interference signal to cancel out echo and interference, utilizing both analog and digital echo cancellation engines to create a data signal with echo cancellation, which is communicated through coaxial cables, and includes isolators to combine data and interference signals for effective echo reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex operation is implemented in CMTS and cable modems to enable simultaneous sending and receiving of signals, then communication efficiency is improved, but echo and interference are generated causing channel interference and reflection issues
Solution Approach 1:
The patent applies echo cancellation technology that generates an anti-echo signal with 180-degree phase offset to cancel out the harmful echo and interference signals. By converting the harmful echo into a beneficial cancellation signal, the system maintains full duplex operation while eliminating the adverse effects. The echo cancellation engine processes the received signal to generate and subtract the echo component, effectively transforming the harmful reflection into a useful noise-reduction mechanism.
2Reliability
If echo cancellation engines are added to CMTS and cable modems to reduce echo and interference, then signal quality is improved, but device complexity increases
Solution Approach 1:
The patent introduces an echo cancellation engine as an intermediary component between the signal receiver and the signal processor. This intermediary module specifically targets and removes echo and interference components from the received signal before further processing. By placing this specialized intermediary component, the system achieves improved signal quality without requiring complete redesign of the entire communication device, thus limiting the increase in complexity to a specific functional module rather than the whole system.
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
The system effectively reduces echo and interference in duplex communications between CMTS and cable modems, improving signal quality by canceling out the echo and adjacent channel interference, thereby enhancing communication efficiency.
Implementation Method 1
A communication system is configured with CMTS and cable modem echo cancellation engines that generate a 180-degree phase offset of the interference signal to cancel out echo and interference
Data Source
AI summary
A method is provided in one example and includes receiving a data signal, receiving an interference signal, wherein the interference signal is copied to create a reference data interference signal, combining the data signal and the interference signal to create a combined signal, using an analog echo cancellation engine on the combined signal to create an analog echo cancellation signal, and using a digital echo cancellation engine on the analog echo cancellation signal to create a data with echo cancellation signal. The data with echo cancellation signal can be communicated using a coaxial cable.