Likelihood Generation Circuit Using Split-Dimension Tables
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Solution Overview
Problem
Conventional techniques for likelihood generation in optical transmission systems, such as 6b4D-2A8PSK, assume ideal soft decision error correction without considering circuit implementation, leading to increased signal processing circuit scale and implementation difficulties.
Innovation Solution
A likelihood generation device that receives code-modulated signals with n−k information bits and k parity bits in an N-dimensional arrangement, using L-dimensional address spaces to determine and update likelihoods for information and parity bits, where L<N, to reduce circuit scale by dividing signal processing into smaller tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ideal soft decision error correction is assumed for likelihood generation in optical transmission systems, then decoding performance is improved, but circuit scale and implementation complexity increase significantly
Solution Approach 1:
The patent segments the N-dimensional address space into multiple L-dimensional sub-address spaces where L < N. This segmentation allows the likelihood generation circuit to process signals using smaller, more manageable tables while maintaining the overall functionality. The received signal is divided into multiple components, each processed by separate sub-circuits that correspond to specific dimensions, thereby reducing the scale of individual circuits while preserving decoding performance.
2Productivity
If N-dimensional modulation is used to increase transmission capacity, then spectral efficiency is improved, but the number of constellation points and processing complexity increase
Solution Approach 1:
The patent transforms the N-dimensional processing problem into multiple L-dimensional sub-problems by selecting specific dimensions for processing. Instead of handling all N dimensions simultaneously in a single complex circuit, the invention processes selected L dimensions separately using dedicated sub-circuits. This dimensional decomposition maintains the high transmission capacity benefits of N-dimensional modulation while reducing the processing complexity of individual circuits.
3Productivity
If the number of constellation points is increased for higher transmission bits per symbol, then transmission capacity is improved, but signal processing complexity and circuit scale increase
Solution Approach 1:
The patent segments the processing of increased constellation points into multiple L-dimensional sub-address spaces. Each sub-circuit handles a portion of the constellation points corresponding to its specific L dimensions, rather than all constellation points simultaneously. This segmentation allows the system to support higher transmission bits per symbol while keeping individual circuit scales manageable through distributed processing across multiple sub-circuits.
Data Source
AI summary
A likelihood generation device is included in a receiving apparatus that receives a code-modulated signal including n−k information bits and k parity bits in N-dimensional arrangement, where N is a natural number greater than or equal to four, and n and k are natural numbers with k<n. The likelihood generation device includes: a temporary likelihood determination unit to determine, by using a table that includes an L-dimensional address space and stores a likelihood in each of the L-dimensional address spaces, likelihoods of an information bit and a parity bit that are transmitted by the code-modulated signal received, where L is a natural number with L<N; and a likelihood correction unit to update, among the likelihoods determined by the likelihood derivation unit, the likelihood of the information bit on a basis of a rule for generation of the parity bit.