Optical Transmitter FEC Interleaving for Burst Error Tolerance
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Solution Overview
Problem
Existing data communication systems face challenges in achieving high data rates and low error rates, particularly in handling burst errors, correlated phase noise, and polarization-dependent impairments.
Innovation Solution
The proposed solution involves a data transmission method that uses staircase forward error correction (FEC) encoding, followed by interleaving and Hamming encoding. This method serially concatenates hard-decision-decodeable staircase coding with soft-decision-decodeable Hamming coding, and employs multiple interleavers to address error correlation and burst errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-order QAM and DSP processing are used to increase data rate, then bandwidth is improved, but system complexity increases
Solution Approach 1:
The patent segments the forward error correction function into two distinct coding layers: outer staircase coding and inner Hamming coding. This segmentation allows each coder to be optimized independently - the staircase coder handles burst errors and correlated phase noise, while the Hamming coder handles random errors, thereby achieving high data rates without proportionally increasing overall system complexity
Solution Approach 2:
The patent creates a composite error correction system by combining two different coding schemes (staircase code and Hamming code) into a concatenated structure. This composite approach leverages the strengths of both coding methods to achieve superior error correction performance at high data rates while managing system complexity through modular design
2Productivity
If advanced techniques like high-order QAM are deployed to meet bandwidth demands, then bandwidth is improved, but tolerance to burst errors and correlated phase noise deteriorates
Solution Approach 1:
The patent segments the error correction function into two distinct coding layers: outer staircase coding and inner Hamming coding. This segmentation allows each coder to be optimized independently - the staircase coder handles burst errors and correlated phase noise, while the Hamming coder handles random errors, thereby achieving high data rates without proportionally increasing overall system complexity
Solution Approach 2:
The patent introduces an intermediary interleaving stage between the outer staircase coding and inner Hamming coding. This interleaver acts as a mediator that redistributes errors from burst patterns to isolated error patterns, enabling the Hamming decoder to effectively correct errors that would otherwise be too correlated for simple parity-check codes to handle
3Reliability
If concatenation of staircase coding and Hamming coding is performed, then error correction capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the forward error correction function into two distinct coding layers: outer staircase coding and inner Hamming coding. This segmentation allows each coder to be optimized independently - the staircase coder handles burst errors and correlated phase noise, while the Hamming coder handles random errors, thereby achieving high data rates without proportionally increasing overall system complexity
Solution Approach 2:
The patent applies preliminary action by using the outer staircase coder to pre-process and protect against the most challenging error patterns (burst errors and correlated phase noise) before the data enters the inner Hamming coding stage. This preliminary protection reduces the burden on the inner decoder and enables more efficient overall error correction
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.