PON Codeword Structure for Fast Synchronization and FEC
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Solution Overview
Problem
The existing 10 G and 1 G EPON systems face challenges with complex synchronization processes and low synchronization speeds due to the use of certain FEC code types and line codes, leading to decreased signal-to-noise ratios and increased bit errors as transmission distance or branch quantity increases.
Innovation Solution
A data encoding and decoding method is introduced at the physical coding sublayer in PON systems, which involves generating a codeword structure with independently distributed valid data, check parts, and synchronization headers, allowing for fast synchronization and improved error correction by transcoding data blocks and using FEC codes like LDPC and Reed-Solomon, and adding indication information in the synchronization header to indicate precoding status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If FEC coding is introduced to improve anti-interference capability and power budget, then error correction capability is improved, but synchronization process complexity increases and synchronization speed decreases
Solution Approach 1:
The codeword structure is segmented into distinct functional parts: synchronization header, payload, and check part. This segmentation allows the synchronization header to be independently processed for fast synchronization, while the payload and check part handle data transmission and error correction separately, thus resolving the contradiction between reliability and synchronization complexity
Solution Approach 2:
The synchronization header is extracted as a separate component from the data payload and check part. By taking out the synchronization function into a dedicated header section, the synchronization process can be performed independently and quickly without being constrained by the complex FEC decoding process, thereby reducing synchronization complexity while maintaining error correction capability
2Reliability
If FEC coding is introduced to improve anti-interference capability, then power budget is increased, but synchronization speed decreases
Solution Approach 1:
The transmission frame is segmented into synchronization header and data payload sections. The synchronization header can be processed independently at higher speed, while the payload section undergoes slower FEC processing, thus achieving fast synchronization without sacrificing power budget
Solution Approach 2:
Synchronization is performed preliminarily using the synchronization header before full FEC decoding of the payload. This preliminary synchronization action enables fast initial alignment, after which the more power-intensive FEC decoding can proceed on the data payload without affecting synchronization speed
Data Source
AI summary
A data encoding method and apparatus and a data decoding method and apparatus in a passive optical network (PON) system include collecting N data blocks at a physical coding sublayer and generating valid data by combining the N data blocks, generating a payload, where the payload includes the valid data, performing FEC encoding on the payload to generate a check part, and generating a codeword structure. The synchronization header may be located at the head or the tail of the codeword structure.