Alignment-Marker Data Streams for Low-Jitter Ethernet Synchronization
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Solution Overview
Problem
Existing Ethernet network data transmission solutions face complexity and high PLL jitter due to the implementation of Phase Locked Loop (PLL)-based clock and data recovery, which complicates clock extraction and synchronization processes.
Innovation Solution
A data processing method that involves first and second FEC encoding, followed by inserting alignment markers into data streams to simplify clock extraction and synchronization, ensuring the baud rate is an integer multiple of the Ethernet common reference clock frequency, thereby reducing PLL complexity and jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PLL-based clock and data recovery is implemented, then clock extraction and synchronization can be performed, but the implementation complexity increases and PLL jitter becomes high
Solution Approach 1:
Alignment markers are inserted into data streams before transmission, preparing the data in advance for easy synchronization. The markers are positioned at specific intervals (P bits from second data stream + W bits alignment marker) to enable the receiver to quickly acquire frame synchronization and inner codeword synchronization without complex PLL circuits
Solution Approach 2:
Alignment markers serve as intermediary elements between the transmitter and receiver, providing clear synchronization points that facilitate clock extraction and data alignment. These markers act as reference signals that simplify the synchronization process, eliminating the need for complex PLL-based approaches
2Ease of operation
If alignment markers are inserted into data streams, then frame synchronization and inner codeword synchronization are simplified, but the data stream structure becomes more complex
Solution Approach 1:
The data stream is segmented into fixed-length frames, with each frame containing P bits from the second data stream followed by W bits of alignment marker. This segmentation creates regular, predictable structures that simplify synchronization operations at the receiver while maintaining manageable complexity through standardized framing
Data Source
AI summary
This application discloses a data processing method. First data processing is performed on a plurality of first data streams obtained through first FEC encoding, to obtain m second data streams. Second FEC encoding has been performed for each of the second data streams, and each codeword obtained through the second FEC encoding includes N bits, where N=K+S. Second data processing is separately performed on the m second data streams to obtain m third data streams. Each of the third data streams includes at least one bit sequence, each bit sequence includes P+W bits, the P bits in each bit sequence are from the second data stream, and the W bits in each bit sequence are an added alignment marker, where P=N×b. Third data processing is performed on the m third data streams to obtain Y modulated symbol streams, where modulation has been performed for each of the modulated symbol streams.