DP-QAM Transmission Coding for Burst Error and Phase Noise Tolerance
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Solution Overview
Problem
Current data communication systems face challenges in achieving high data rates and low error rates, particularly in optical communication links, due to physical limitations and impairments such as burst errors and phase noise.
Innovation Solution
The implementation of a data transmission method that serially concatenates staircase forward error correction (FEC) and Hamming FEC, combined with multiple interleavers, to enhance error tolerance and performance, using staircase coded blocks, Hamming codewords, and pilot symbols within dual-polarized quadrature-amplitude-modulation (DP-QAM) symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-order QAM and DSP processing are used to increase data rate, then bandwidth and data rate are improved, but system complexity and sensitivity to errors increase
Solution Approach 1:
The patent divides the error correction function into two separate coding layers: outer staircase coding and inner Hamming coding. This segmentation allows each code to be optimized for specific error types, with staircase coding handling burst errors and Hamming coding handling random errors, thereby achieving high reliability without excessive complexity in a single coding scheme
Solution Approach 2:
The patent employs a composite coding structure combining two different error correction codes (staircase code and Hamming code) in a serial concatenation framework. This composite approach leverages the strengths of both codes to achieve superior error correction performance that neither code could achieve alone, resolving the contradiction between data rate and reliability
2Reliability
If advanced error correction techniques are implemented, then error tolerance is improved, but processing complexity and computational overhead increase
Solution Approach 1:
The error correction function is segmented into outer staircase coding for burst errors and inner Hamming coding for random errors. This segmentation allows simpler Hamming decoding to handle the majority of random errors while staircase decoding handles residual burst errors, reducing overall processing complexity compared to using a single complex code
Solution Approach 2:
The outer staircase code performs preliminary error correction on burst errors before the inner Hamming code handles remaining random errors. This preliminary action reduces the burden on the inner decoder, lowering overall processing complexity while maintaining high error tolerance
3Reliability
If interleaving is applied to distribute errors, then tolerance to burst errors is improved, but processing time and latency increase
Solution Approach 1:
The patent applies interleaving specifically to the outer staircase code to distribute burst errors across multiple code blocks. This segmented approach to interleaving provides burst error protection where most needed while keeping the inner Hamming code processing simple and fast, balancing reliability improvement with minimal time loss
Solution Approach 2:
Interleaving is applied locally to the outer code structure rather than uniformly across the entire transmission. This local quality approach provides burst error tolerance exactly where needed in the outer staircase code while maintaining fast processing in the inner Hamming code, reducing overall latency
Data Source
AI summary
The present invention relates to data communication systems and methods thereof. More specifically, embodiments of the present invention provide a data transmission method. Data are encoded with staircase encoder, and staircase coded blocks are first interleaved then combined into outer code frames. Code frames additionally include sync words and padding bits. A second interleaving is applied to the bits of the code frames, and Hamming encoding is performed on the output of the second interleaver. Hamming codewords are Gray-mapped to dual-polarized quadrature-amplitude-modulation (DP-QAM) symbols, and a third interleaving of the symbols from a set of successive Hamming codewords is performed. Pilot symbols are inserted periodically into the stream of DP-QAM symbols. There are other embodiments as well.