Multi-Lane 8b/10b Alignment Symbol Interleaving for 10 Gb Ethernet
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Solution Overview
Problem
Current 10 Gb Ethernet network interfaces face challenges in efficiently aligning and encoding data across multiple lanes due to differing propagation delays and frequency differences, leading to misalignment and signal quality issues.
Innovation Solution
A network interface system that includes a substitutor module to replace idle symbols with alignment symbols, interleaver modules to interleave data and alignment symbols, and decoders to align and decode data across lanes, utilizing an 8/10 encoding scheme for efficient data transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data is transmitted across multiple lanes without alignment symbols, then transmission speed is maintained, but signal misalignment occurs due to differing propagation delays
Solution Approach 1:
The substitutor module proactively inserts alignment symbols at predetermined intervals before data transmission begins. These alignment symbols are placed in advance to establish reference points that enable subsequent synchronization of multiple lanes, preventing misalignment caused by propagation delay differences.
Solution Approach 2:
Alignment symbols serve as intermediary reference elements between the transmitted data and the receiving end. These symbols act as mediators that allow the receiver to measure and compensate for propagation delay variations across different lanes, enabling precise synchronization without sacrificing transmission speed.
2Device complexity
If idle symbols are transmitted without replacement, then device complexity is reduced, but DC offset and signal quality issues arise
Solution Approach 1:
The substitutor module extracts and removes idle symbols from the data stream before transmission. By taking out these problematic idle symbols and replacing them with alignment symbols, the system eliminates the source of DC offset and signal quality issues while maintaining a relatively simple device architecture.
3Manufacturing precision
If alignment symbols are inserted periodically, then lane synchronization is achieved, but data transmission efficiency decreases
Solution Approach 1:
Instead of inserting alignment symbols continuously or excessively, the substitutor module applies partial action by inserting them only at specific periodic intervals where synchronization is needed. This partial insertion maintains lane alignment precision while minimizing the impact on data transmission efficiency.
4Reliability
If 8/10 encoding is applied to each lane, then data integrity is improved, but bandwidth utilization decreases
Solution Approach 1:
The system changes the encoding parameters by applying 8/10 encoding to each lane, which adds redundancy bits for error detection and correction. While this improves data integrity, it reduces bandwidth utilization due to the increased number of bits required for the same amount of data.
Data Source
AI summary
A network interface includes N input lanes that receive data symbols and idle symbols. A substitutor module periodically replaces an idle symbol on each input lane with a corresponding alignment symbol to form an alignment group. M interleaver modules each interleave a portion of the data symbols and alignment symbols onto a corresponding transmit lane based on an interleaving pattern that provides each transmit lane with N/M alignment symbols from the alignment group. M is an integer greater than 1 and N is greater than M. In some features the substitutor module periodically replaces successive idle symbols on each lane with alignment symbols to form corresponding alignment groups. An interleaver module interleaves the data symbols and alignment groups onto M transmit lanes according to an interleaving pattern that provides each transmit lane with one of the alignment groups.