Flexible FEC Frame Encoding for PON Bandwidth Overhead
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Solution Overview
Problem
Current PON systems use uniform FEC codes to ensure bit error rate compliance, leading to inefficient bandwidth allocation and increased overhead due to varying channel quality between OLT and ONUs.
Innovation Solution
Implementing a flexible FEC coding scheme that adapts to the channel quality of individual ONU connections, allowing for differentiated encoding and decoding based on the type of FEC code indicated in the physical frame structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform FEC code is used for all ONUs, then bit error rate requirement is met for all users, but bandwidth overhead increases and bandwidth utilization decreases
Solution Approach 1:
The patent applies local quality by allowing different ONUs to use different FEC codes based on their individual channel conditions. Each ONU can be configured with an appropriate FEC code level (first level for poor channels, second level for good channels), so that each user receives localized optimization rather than uniform treatment. This resolves the contradiction by meeting BER requirements only where needed while reducing overhead for users with better channels.
Solution Approach 2:
The patent introduces dynamic adaptability by enabling the OLT to flexibly allocate different FEC codes to different ONUs based on real-time or measured channel quality. The system transitions from a static uniform FEC approach to a dynamic differentiated approach where FEC code selection can be adjusted per ONU and potentially over time, optimizing the balance between reliability and bandwidth efficiency.
2Reliability
If high-performance FEC code is used to ensure BER for poor channel conditions, then reliability improves for worst-case users, but bandwidth overhead increases for all users
Solution Approach 1:
The patent implements local quality by matching FEC code performance to local channel conditions. ONUs with poor channel quality receive high-performance FEC codes (first level) to ensure reliable communication, while ONUs with good channel quality receive lower-performance FEC codes (second level). This localized optimization ensures that high-performance FEC is applied only where necessary, improving reliability for worst-case users without unnecessarily reducing bandwidth utilization for all users.
Solution Approach 2:
The patent applies parameter changes by varying the FEC code parameters (code rate, block length, etc.) based on channel quality measurements. The OLT can select from multiple FEC code configurations and assign appropriate parameters to each ONU, changing the FEC parameters dynamically rather than using a fixed uniform configuration. This allows the system to optimize the trade-off between reliability and bandwidth utilization by adjusting FEC parameters to match actual channel conditions.
3Ease of operation
If all user data is encoded with the same FEC, then system complexity is reduced and ease of operation is improved, but bandwidth allocation efficiency decreases
Solution Approach 1:
The patent applies universality by designing a system where a single OLT and ONU architecture can handle multiple FEC code types through standardized interfaces and protocols. The OLT is configured to support both first-level and second-level FEC codes, and ONUs are designed to decode multiple FEC types or their specific assigned type. This multi-functional capability allows the system to operate in simplified mode (uniform FEC) when needed while also supporting differentiated FEC allocation for improved bandwidth efficiency, resolving the contradiction between operational simplicity and allocation efficiency.
Data Source
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AI summary
Provided are an encoding method, a decoding method, a communication node, and a storage medium. The encoding method includes the following: An uncoded physical frame is acquired, where the uncoded physical frame includes a first data block and a second data block, and the first data block includes a type of a flexible forward error correction, FEC, code. The second data block is encoded according to the type of the flexible FEC code.