Network Test Apparatus for PAM Signal Error Detection
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Solution Overview
Problem
In 400 GbE networks based on the IEEE 802.3 standard, the high bit rate and low noise immunity of PAM signals lead to frequent errors, making it difficult to determine when an Uncorrectable Codeword occurs, resulting in communication data loss.
Innovation Solution
A network test apparatus with a reception unit for receiving PAM codewords, an arithmetic processing unit to count symbol errors per codeword using FEC, and a display unit to indicate whether multiple symbol errors are corrected, allowing for the determination of Correctable or Uncorrectable Codewords based on set thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If PAM signals with high bit rate are used for 400 GbE networks, then transmission speed is improved, but noise immunity deteriorates leading to frequent errors
Solution Approach 1:
The patent applies parameter changes by implementing FEC coding schemes that transform the signal parameters. Specifically, it uses codeword-based error correction where multiple PAM symbols are grouped into codewords, and redundancy is added through systematic encoding. This transforms the original high-speed but error-prone PAM signals into corrected codewords that maintain the high transmission speed while improving reliability through mathematical error correction capabilities.
2Reliability
If FEC is applied to correct errors in PAM signals, then reliability is improved, but device complexity increases due to coding and decoding operations
Solution Approach 1:
The patent applies segmentation by dividing the continuous data stream into discrete codeword units for independent error correction processing. Each codeword is treated as a separate entity with its own error correction capability, allowing the system to process errors in manageable segments rather than attempting to correct all errors in the entire data stream simultaneously. This reduces the instantaneous processing complexity while maintaining overall reliability.
Solution Approach 2:
The patent uses copying by creating redundant copies of data within the FEC codeword structure. Systematic FEC encoding generates parity symbols that are copies of the original data symbols transformed through mathematical operations. These copied redundant symbols enable error detection and correction without requiring complex real-time analysis of the entire signal, thereby reducing processing complexity.
3Reliability
If the number of FEC symbols per codeword is increased to improve error correction, then reliability is improved, but the time required for error correction increases
Solution Approach 1:
The patent applies partial action by implementing error correction for only the necessary number of symbols within each codeword rather than processing all symbols uniformly. The system determines the actual number of errors present and applies correction only to that extent, avoiding unnecessary processing of already-correct symbols. This reduces the effective error correction time while maintaining the reliability benefits of having a sufficient number of FEC symbols in the codeword structure.
Data Source
AI summary
An object of the present disclosure is to determine whether or not a codeword in which a plurality of symbol errors are corrected occurs, and to detect a potential network failure. According to the present disclosure, there is provided a network test apparatus including: a reception unit that receives codewords generated by using pulse amplitude modulation (PAM); an arithmetic processing unit that measures the number of symbol errors per codeword included in the codewords by using forward error correction (FEC), and counts the number of codewords for each number of symbol errors per codeword; and a display unit, in which whether or not there is a codeword in which a plurality of symbol errors are corrected is displayed on the display unit by using the number of codewords.