Spatially Coupled GEL Codes for Low-Error-Floor FEC
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Solution Overview
Problem
Existing spatially coupled forward error correction (FEC) codes face limitations in achieving low-latency, high-throughput, and high-rate applications with a low error-floor and low-complexity decoding, particularly in optical communications, as they struggle to balance performance, latency, and error correction capabilities.
Innovation Solution
The use of generalized error location (GEL) codes as component codes in spatially coupled constructions, where codewords are formed by sharing symbols across blocks and generating check symbols from previous blocks, enabling efficient encoding and decoding with low latency and high throughput while maintaining a low error-floor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spatially coupled FEC codes are used, then high throughput is achieved, but error-floor remains high and latency is excessive
Solution Approach 1:
The code is segmented into multiple blocks where each block can be decoded independently with a fixed decoding window size. This segmentation allows the decoder to process complete codewords without waiting for the entire stream, reducing latency while maintaining low error-floor through proper block design
Solution Approach 2:
The invention changes key parameters including using generalized error location codes with specific minimum distance properties, adjusting the decoding window size to be finite rather than infinite, and modifying the spatial coupling structure to achieve both low latency and low error-floor simultaneously
2Device complexity
If binary BCH codes with small error correction capability are used as component codes, then decoding complexity is reduced, but error correction performance deteriorates
Solution Approach 1:
The invention changes the component code parameters by using generalized error location codes with higher minimum distance than conventional BCH codes. This parameter change improves error correction capability while the codes are designed to maintain manageable decoding complexity through efficient algorithms
Solution Approach 2:
The invention creates a composite coding structure by spatially coupling generalized error location codes with specific algebraic properties. This composite structure combines the error correction strength of GEL codes with the low complexity of spatially coupled decoding architectures
3Reliability
If spatial coupling with infinite sequence is used, then error correction performance is improved, but latency increases excessively
Solution Approach 1:
The infinite spatially coupled sequence is segmented into finite blocks with a predetermined decoding window size. Each block forms a complete codeword that can be decoded independently, eliminating the need to wait for an infinite sequence while preserving the error correction benefits of spatial coupling
Solution Approach 2:
Instead of using the full infinite sequence, the invention uses a partial sequence within a finite decoding window that is sufficient for achieving the required error correction performance. This partial action achieves the necessary reliability without the excessive latency of processing the entire infinite sequence
Data Source
AI summary
The present disclosure provides an encoding and decoding device implementing an improved forward error correction (FEC) coding/decoding method. In particular, the encoding device is configured to encode a stream of data symbols using a spatially coupled code (e.g. staircase codes, braided block codes or continuously interleaved block codes), wherein at least one generalized error location (GEL) code is used as a component code of the spatially coupled code. Accordingly, the decoding device is configured to decode a sequence of encoded symbol blocks using a spatially coupled code, wherein at least one GEL code is used as a component code of the spatially coupled code. Thereby, a suitable spatially coupled FEC code that allows for very low-latency, high-throughput, high-rate applications with a low-complexity decoding procedure, and allows for mitigation of the error-floor, is designed.