Diagonal Interleaving Codewords for Low-Latency Error Correction
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Solution Overview
Problem
Existing communication networks face inefficiencies in error correction due to the use of single level coding in helical interleavers, which does not adequately protect data in modern communications systems.
Innovation Solution
A method and circuit that form codewords with two sets of bits, a horizontal part in a current sequence and a diagonal part in multiple past sequences, ensuring each bit is protected by two codewords, and grouping codewords such that each has no bits in common within its group but shares bits with codewords in other groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single level coding is used in helical interleavers, then device complexity is reduced, but error correction reliability deteriorates
Solution Approach 1:
The invention divides the codeword into two distinct parts: a horizontal part containing bits from the current sequence and a diagonal part containing bits from multiple past sequences. This segmentation allows each part to be protected by different coding mechanisms, with the horizontal part providing immediate error correction and the diagonal part providing additional redundancy across multiple sequences, thereby improving overall reliability without requiring a complete redesign of the coding structure.
Solution Approach 2:
The invention transitions from single-level coding to a two-dimensional coding structure where codewords are arranged in both horizontal and diagonal dimensions. The horizontal part operates in the current sequence dimension while the diagonal part extends into the temporal dimension of past sequences. This dimensional expansion enables more robust error correction by distributing protection across multiple dimensions, effectively resolving the contradiction between reliability and complexity.
2Reliability
If two part codewords with multiple group protection are used, then error correction reliability is improved, but decoder latency increases
Solution Approach 1:
The invention prepares the diagonal part of the codeword in advance by storing bits from past sequences in a buffer structure organized by diagonal groups. When decoding is needed, the previously received diagonal bits are already available and can be immediately combined with the current horizontal bits. This preliminary preparation of diagonal components eliminates waiting time during decoding, allowing the entire codeword to be decoded simultaneously without increasing latency.
Solution Approach 2:
The invention implements a dynamic buffering structure where diagonal parts from multiple past sequences are maintained in memory with optimized access patterns. The buffer dynamically manages the storage and retrieval of diagonal bits based on the current decoding requirements, enabling efficient simultaneous access to both horizontal and diagonal components. This dynamic management ensures that increased protection through multiple groups does not result in increased decoding latency.
3Reliability
If codewords are grouped such that each codeword shares bits with codewords in other groups, then error protection is enhanced, but device complexity increases
Solution Approach 1:
The invention creates diagonal copies of bits from past sequences and stores them in a structured buffer where they can be efficiently accessed. Instead of managing complex shared memory structures, the system creates explicit copies of the necessary diagonal bits and organizes them in predetermined locations. This copying approach simplifies the management of shared bits across multiple codeword groups, as each group can independently access its required diagonal copies without complex coordination, thereby reducing device complexity while maintaining enhanced error protection.
Data Source
AI summary
A circuit and method form a codeword including parity and message bits, as follows. Each codeword has a first part in a current sequence (e.g. a current OTN-row) that is to be now transmitted and second part spread across multiple past sequences (e.g. previously prepared and transmitted OTN-rows). The codewords are grouped into multiple groups such that each codeword within a group has no bit in common with another codeword in that group. Moreover, each codeword has a bit in common with a different codeword in a different group.