GPON Downlink Frame Synchronization With FEC Header Protection
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Solution Overview
Problem
The high bit error rate of the frame header in GPON systems leads to asynchronous states in optical network terminals, compromising the reliability of downlink data transmission, especially in 10G GPON where the increased downlink rate exacerbates this issue.
Innovation Solution
Implementing forward error correction (FEC) encoding using the Reed-Solomon code RS (255, 239) on the synchronization domain of downlink frames, which includes a 16-byte FEC check domain to correct errors in the physical synchronization and identifier domains, ensuring reliable frame synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the downlink rate is increased from 2.5 Gbps to 10 Gbps in 10G GPON, then the transmission speed is improved, but the bit error rate of the frame header is greatly increased
Solution Approach 1:
The patent applies preliminary action by performing FEC encoding on the Psync and Ident domains before transmission. The optical line terminal encodes these critical synchronization fields in advance using forward error correction, so that even if bit errors occur during high-speed transmission, the optical network terminal can correctly identify and correct them, maintaining reliable frame synchronization at 10 Gbps.
2Reliability
If FEC encoding is applied to the synchronization domain, then the reliability of frame synchronization is improved, but the device complexity is increased
Solution Approach 1:
The patent applies local quality by selectively applying FEC encoding only to the Psync and Ident domains within the frame header, rather than encoding the entire frame. This targeted approach provides enhanced error protection for the most critical synchronization fields while avoiding the excessive complexity of system-wide FEC, achieving a balanced solution for 10G GPON.
Data Source
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AI summary
Disclosed in the present invention are a method and apparatus for processing downlink frame synchronization in a Gigabit-capable passive optical network (GPON) system, wherein the method comprises: carrying out forward error correction (FEC) encoding on data in a synchronization domain of a downlink frame of the GPON system, wherein the synchronization domain includes a physical synchronization (Psync) domain and an identifier (Ident) domain; filling the FEC encoded data into an FEC check domain provided in the downlink frame; and sending the downlink frame. By virtue of the present invention, the effect of improving the reliability of GPON downlink frame synchronization is achieved.