Set-Partition Viterbi Equalization for Non-Binary Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Soft-output equalization for non-binary, multilevel modulation in receivers faces challenges with increasing computational effort and storage requirements as the constellation size grows, particularly in dispersive channels with intersymbol interference.
Innovation Solution
The implementation of Soft-Output-Viterbi (SOV) equalization using set-partition labeling and multilevel trellis processing, which reduces computational complexity and storage needs by partitioning symbols into sets based on least-significant bit values, allowing for efficient decoding of multibit labels in receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft-output equalization is applied to non-binary multilevel modulation, then decoding performance is improved, but computational complexity and storage requirements increase with constellation size
Solution Approach 1:
The patent applies segmentation by dividing the multibit label into multiple bit positions (e.g., most significant bit and least significant bit) and processing each bit position separately through independent Viterbi equalization passes. This segmentation reduces the computational complexity from exponential growth with constellation size to linear growth, while still achieving soft-output decoding performance benefits
2Reliability
If soft-output equalization is applied to non-binary multilevel modulation, then decoding performance is improved, but storage requirements increase with constellation size
Solution Approach 1:
The patent reduces storage requirements by segmenting the decoding process into multiple passes, where each pass processes only one bit position. This eliminates the need to store complete soft-output information for all constellation points simultaneously, reducing memory requirements from exponential to linear with respect to constellation size
3Productivity
If conventional soft-output equalization is used for higher-order modulation schemes, then more bits per symbol are transmitted, but the computational effort grows excessively
Solution Approach 1:
The patent enables higher-order modulation by segmenting the equalization process into multiple bit-position-specific passes. Each pass processes only one bit with reduced complexity, allowing the system to handle higher constellation sizes (e.g., PAM-4, PAM-8) that would be computationally prohibitive with conventional soft-output equalization
Solution Approach 2:
The patent implements dynamic adaptability by allowing the number of passes and processing depth to be adjusted based on the specific modulation scheme and channel conditions. This dynamic approach optimizes the balance between computational effort and decoding performance for different higher-order modulation scenarios
Data Source
AI summary
A method comprises: receiving, from a communication channel, non-binary multilevel symbols that represent corresponding multibit labels each including at least a least-significant bit (LSB) and a most-significant bit (MSB), the non-binary multilevel symbols mapped to the multibit labels according to set-partition labeling, which partitions the non-binary multilevel symbols between a first set and a second set according to a first value and a second value of the LSB, respectively; digitizing the non-binary multilevel symbols to produce symbol samples; and performing Soft-Output-Viterbi (SOV) equalization of the non-binary multilevel symbols based on the symbol samples, to produce decoded symbol information corresponding to the non-binary multilevel symbols.