Parallel Binary Distribution Matcher for Low Latency Probabilistic Shaping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for probabilistic shaping in digital communication systems, such as constant composition distribution matching (CCDM), require long output sequences to achieve good performance, leading to high latency and making hardware implementation impossible due to sequential operation of mapping and demapping algorithms.
Innovation Solution
A low complexity method and system using parallel binary distribution matchers and dematchers that perform subset ranking and deranking, reducing serialism by breaking down the target symbol sequence into separate parallel sequences, allowing for integer arithmetic and efficient CPU usage, power consumption, and network bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If constant composition distribution matching (CCDM) is used to achieve good performance, then the probability distribution accuracy is improved, but the sequence length must be increased to thousands of symbols which increases latency
Solution Approach 1:
The patent divides the distribution matching process into multiple independent binary distribution matchers that operate in parallel. Each binary distribution matcher handles a specific bit position or subset of bits, allowing the overall matching process to be completed much faster than sequential processing while maintaining the required probability distribution accuracy through the coordinated operation of these parallel components.
2Measurement precision
If sequential mapping and demapping algorithms are used to achieve good performance, then the probability distribution matching accuracy is improved, but hardware implementation becomes impossible due to high latency
Solution Approach 1:
The sequential algorithm is segmented into multiple independent binary distribution matchers that can operate simultaneously in hardware. Each matcher is a self-contained unit that processes specific aspects of the distribution matching, and their parallel operation enables hardware implementation while preserving the accuracy characteristics of the original sequential algorithm.
Solution Approach 2:
The patent transitions from time-sequential processing to spatial-parallel processing by distributing the matching operations across multiple parallel binary distribution matchers. This dimensional change from sequential time steps to parallel spatial operations enables hardware implementation without sacrificing accuracy.
3Speed
If parallel binary distribution matchers are used to reduce latency, then processing speed is improved, but the system complexity increases
Solution Approach 1:
The complex distribution matching function is segmented into multiple simpler binary distribution matchers. Each matcher handles a specific aspect of the matching process, and their individual simplicity allows for efficient parallel implementation. The overall system achieves high processing speed through parallelism while each component remains relatively simple.
Solution Approach 2:
The patent changes the operational parameters of the distribution matchers to binary operations, which are inherently simpler and more suitable for parallel hardware implementation. By expressing the distribution matching in terms of binary decisions and operations, the system achieves both speed improvement through parallelism and reduced individual component complexity.
Data Source
AI summary
A communication system includes a data source to receive a block of bits, a processor, a memory, in connection with the processor, to store a distribution matcher associated with a probability mass function (PMF) configured to match a block of equally likely input bits to a fixed number of output bits with values distributed according to the PMF of the distribution matcher using the processor. In this case, the distribution matcher contains a set of parallel binary distribution matchers which specify fully a target PMF, and a transmitter front end to transmit a block of shaped bits over a communication channel, such that bits in a sequence of the blocks of shaped bits are distributed according to the target PMF.