Protected Communication Link Switching Using Soft Quality Ranks
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Solution Overview
Problem
Existing communication systems that use Forward Error Correction (FEC) codes for switching between primary and secondary links often rely on unreliable binary indications, leading to sub-optimal or erroneous selection decisions, especially under high FEC code rates or difficult channel conditions.
Innovation Solution
The method involves computing and using 'soft quality ranks' based on both FEC and error detection codes, such as Cyclic Redundancy Check (CRC), to select the better-performing data frames, allowing for frame-by-frame switching between primary and secondary links, even when both contain errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If binary indications from FEC code are used for link selection, then device complexity is reduced, but measurement precision and selection accuracy deteriorate
Solution Approach 1:
The patent transforms the binary FEC indication into a multi-level soft quality rank by introducing additional parameters (error counts, confidence values) that provide finer granularity in link quality assessment, resolving the contradiction between simplicity and accuracy
Solution Approach 2:
The patent introduces soft quality ranks as an intermediary metric between the raw binary FEC indication and the final link selection decision, enabling more nuanced comparison while maintaining systematic decision-making
2Measurement precision
If error detection codes like CRC are added to improve selection accuracy, then measurement precision improves, but device complexity and processing overhead increase
Solution Approach 1:
The patent performs error detection coding (CRC) and soft quality rank computation in advance during the receiving and decoding process, so that when selection is needed, the quality metrics are already available, reducing real-time decision complexity
Solution Approach 2:
The error detection code (CRC) serves dual purposes: it detects errors in the data and simultaneously provides quality indication information for link selection, making the system self-sufficient without requiring separate monitoring mechanisms
3Reliability
If frame-by-frame switching is implemented to select the better link, then reliability improves, but loss of time increases due to continuous monitoring and switching decisions
Solution Approach 1:
The patent continuously computes soft quality ranks for both links in parallel as data is received, maintaining ready-to-use quality metrics without interruption, enabling immediate switching decisions when needed
Solution Approach 2:
The patent pre-computes soft quality ranks during the normal data reception and decoding process, so that when a switch is needed, the decision can be made immediately based on already-available metrics, minimizing switching delay
Data Source
AI summary
A method for communication includes receiving first and second data frames over first and second communication links, respectively, the first and second data frames containing respective first and second replicas of data, which has been encoded with a Forward Error Correction (FEC) code. The FEC code in the received first and second data frames is decoded, and respective first and second soft quality ranks of the first and second data frames are computed based on the decoded FEC code. One of the first and second replicas of the data are selected based on the first and second soft quality ranks. The selected one of the first and second replicas of the data is provided as output.