Echo Canceller Training on Quiet Upstream Subcarriers
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Solution Overview
Problem
In hybrid Fiber-Coaxial (HFC) infrastructures supporting DOCSIS 4.0 full duplex (FDX) communication, echo cancellers face challenges in training during periods of significant correlation between downstream signals and residual noise, leading to cancellation depth loss and impaired communication quality.
Innovation Solution
The solution involves automatically training echo cancellers during low activity times in upstream subcarriers, utilizing Echo Canceller Training Opportunities (ECTO) or other quiet periods. This allows the echo canceller to predict and cancel echoes during high activity times by adjusting frequency domain filters based on statistics gathered during training.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If echo canceller training is performed during high upstream activity periods, then training opportunities increase, but echo cancellation performance deteriorates due to signal correlation and noise
Solution Approach 1:
The system performs echo canceller training during quiet periods (low upstream activity) in advance, so that the trained filter coefficients are ready before high activity periods begin. This preliminary training avoids the correlation and noise problems that would occur if training were attempted during high activity periods, while still ensuring the canceller is prepared to handle upcoming high activity periods effectively.
2Reliability
If echo canceller training is avoided during high upstream activity, then echo cancellation performance is maintained, but training opportunities are lost
Solution Approach 1:
The system continuously monitors upstream activity levels and continuously performs training during quiet periods whenever conditions permit. This continuous opportunistic training ensures that training occurs as frequently as possible without compromising performance, maximizing the utilization of available quiet periods while maintaining cancellation effectiveness during high activity periods.
3Measurement precision
If automatic training on quiet subcarriers is implemented, then training effectiveness improves, but system complexity increases
Solution Approach 1:
The system automatically detects quiet periods in the upstream signal and autonomously performs training during these periods without requiring external control or manual intervention. The echo canceller monitors its own operating conditions, identifies suitable training opportunities, and executes training autonomously, thereby improving training effectiveness while adding minimal operational complexity.
Data Source
AI summary
The systems and methods described provide a solution for automatic training of echo canceller (EC) in upstream signal receivers on sub-carriers experiencing low activity in the upstream communication. The solution can include one or more processors identifying a plurality of bins (e.g., EC bins). Each bin of the plurality of bins can correspond to a portion of a frequency range of a cable line. The one or more processors can determine that a power level of an echo signal of each of a bin of the plurality of bins and one or more bins adjacent to the bin exceed a respective threshold for the power level. The one or more processors can train an echo canceller of the echo signal for the bin, responsive to the determining.