Optical Transmitter Coding Layout for Burst Errors and Phase Noise
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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 systems, 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 with multiple interleavers, combined with pilot symbols, to enhance error tolerance and data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If advanced techniques like 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 impairments increase
Solution Approach 1:
The patent divides the forward error correction function into two separate stages: staircase encoding for burst error correction and Hamming encoding for random error correction. This segmentation allows each encoder to be optimized for its specific error type, improving overall efficiency without requiring a single complex encoding system to handle all error types simultaneously.
Solution Approach 2:
The patent combines two different encoding schemes (staircase code and Hamming code) into a hybrid error correction system. This composite approach leverages the strengths of both encoding methods - staircase code's ability to handle burst errors and Hamming code's efficiency with random errors - creating a more robust system than either encoding scheme alone.
2Reliability
If staircase encoding and Hamming encoding are serially concatenated with multiple interleavers, then error tolerance is improved, but device complexity increases
Solution Approach 1:
The patent divides the error correction function into two separate stages: staircase encoding for burst error correction and Hamming encoding for random error correction. This segmentation allows each encoder to be optimized for its specific error type, improving overall efficiency without requiring a single complex encoding system to handle all error types simultaneously.
Solution Approach 2:
The patent introduces multiple interleaving stages that operate at different levels of the data structure. The first interleaver operates on staircase coded blocks, while the second interleaver operates on the combined output. This multi-dimensional interleaving approach distributes errors across different codewords and time slots, enhancing error tolerance without requiring each individual encoder to be overly complex.
3Reliability
If multiple interleaving stages are applied to staircase coded blocks and code frames, then tolerance to burst errors and phase noise is increased, but processing time and complexity increase
Solution Approach 1:
The patent applies the first interleaving operation immediately after staircase encoding, before the data enters the Hamming encoder. This preliminary interleaving distributes burst errors across multiple staircase coded blocks, preventing any single Hamming codeword from receiving a concentrated burst of errors that would be difficult to correct. This early error distribution reduces the processing burden on subsequent decoding stages.
Solution Approach 2:
The patent introduces multiple interleaving stages that operate at different levels of the data structure. The first interleaver operates on staircase coded blocks, while the second interleaver operates on the combined output. This multi-dimensional interleaving approach distributes errors across different codewords and time slots, enhancing error tolerance without requiring each individual encoder to be overly complex.
4Reliability
If pilot symbols are inserted periodically into the stream, then tolerance to correlated phase noise is improved, but data transmission efficiency decreases
Solution Approach 1:
The patent inserts pilot symbols periodically at specific intervals within the data stream, rather than continuously. This partial insertion provides sufficient phase noise reference points for correction while minimizing the proportion of bandwidth dedicated to non-data symbols. The periodic placement allows the system to achieve adequate phase tracking performance with a reduced overhead compared to continuous pilot insertion.
Data Source
AI summary
An optical transmitter includes a first encoder, a first interleaver, a second encoder, a mapper, a second interleaver, and a frame generator. The first encoder is configured to encode data using a staircase code to generate first codewords. The first interleaver is configured to interleave the first codewords using convolutional interleaving to spread a transmission order of the first codewords. The second encoder is configured to encode the interleaved first codewords using a second code to generate second codewords. The mapper is configured to map the second codewords to transmit symbols. The second interleaver is configured to interleave the transmit symbols to distribute the transmit symbols between pilot symbols. The frame generator is configured to generate a transmit frame including the interleaved transmit symbols and the pilot symbols.