SNR-Based BER Reporting Beyond the FEC Threshold

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Solution Overview

Problem

Conventional methods fail to accurately measure bit error ratio (BER) beyond the forward error correction (FEC) threshold, rendering it impossible to determine link viability and necessitate immediate failure reporting, which lacks actionable insights for network operators.

Innovation Solution

Utilizing signal-to-noise ratio (SNR)-based calculations to extrapolate BER beyond the FEC threshold, enabling accurate determination and reporting of pre-FEC BER, along with optical link parameters like chromatic dispersion and polarization dependent loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional BER measurement methods are used, then BER can be accurately determined below the FEC threshold, but BER measurement becomes impossible above the FEC threshold

Engineering Contradiction:

ImproveBER measurement accuracyVSAvoidBER measurement range

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the measurement parameter from direct BER counting to SNR-based BER calculation. By measuring SNR (signal-to-noise ratio) and using it to calculate BER through established relationships, the system can determine BER values even when the link operates above the FEC threshold where conventional counting methods fail.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces SNR as an intermediary measurement parameter. Instead of directly measuring BER which becomes impossible above FEC threshold, the system measures SNR (which can be obtained even above threshold) and uses it as a mediator to infer BER values through known SNR-BER relationships for the specific modulation and coding scheme.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If FEC is used to enable operation at lower SNR values, then high data rates can be achieved, but BER reporting is lost when operating above the FEC threshold

Engineering Contradiction:

Improvedata rateVSAvoidBER reporting capability

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism where SNR measurements are continuously taken and used to calculate and report BER values. This feedback loop provides network operators with ongoing information about link quality and BER performance, enabling them to make informed decisions about link adjustments even when operating above the FEC threshold.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

SNR serves as an intermediary that bridges the gap between FEC operation and BER reporting. By measuring SNR (which reflects the actual signal quality) and converting it to BER through calculation, the system maintains BER reporting capability across the full range of FEC operating conditions, including above-threshold scenarios.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the link operates above the FEC threshold, then the FEC can no longer correct all errors, but the system still needs to provide link viability assessment

Engineering Contradiction:

Improveerror correction capabilityVSAvoidlink viability assessment

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the mechanical/error-counting-based BER determination method with an SNR-based calculation approach. This substitution allows the system to assess link viability through SNR measurements and calculated BER values, providing operators with quantitative information about link performance and the potential for recovery through adjustments even when operating above the FEC threshold.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12381624B2Signal-to-noise ratio-based bit error ratio calculation for reporting beyond a forward error correction threshold

Publication Date: 2025.08.05 CIENA CORP

AI summary

Signal-to-noise ratio (SNR)-based bit error ratio (BER) calculations for reporting beyond a forward error correction (FEC) threshold include measuring signal-to-noise ratio (SNR) of a first signal; extrapolating the SNR of a first signal to determine an SNR of a second signal; and determining a pre-FEC bit error rate (BER) for the second signal based on the determined SNR of the second signal. The process can further include reporting the determined pre-FEC BER. The measuring and extrapolating can be used when the second signal is beyond the FEC threshold.