Probabilistic Constellation Shaping for Lower-Power Optical Encoding
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Solution Overview
Problem
Existing optical communication systems face challenges in increasing bandwidth capacity and reducing power consumption due to channel impairments and high power usage, necessitating improved constellation shaping techniques.
Innovation Solution
Implementing probabilistic constellation shaping through a recursive constant composition distribution matcher encoding and decoding procedure to optimize the distribution of transmission symbols, limiting high-energy symbols and enhancing signal quality while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional constellation shaping is used to increase bandwidth capacity, then transmission rate is improved, but power consumption increases due to high-energy symbols
Solution Approach 1:
The patent applies parameter changes by modifying the distribution of constellation point energies through probabilistic shaping. Specifically, it changes the probability parameters of selecting high-energy versus low-energy constellation points, thereby optimizing the energy distribution to reduce average power consumption while maintaining bandwidth capacity through the recursive mapping procedure that adapts the number of high-energy symbols (n1) based on channel conditions
Solution Approach 2:
The patent implements dynamics by making the constellation shaping adaptive through recursive procedures that dynamically adjust the distribution of transmission symbols. The system dynamically determines the optimal number of high-energy symbols (n1) based on channel state information and recursively maps information bits to amplitude indicators, allowing the energy distribution to adapt in real-time to changing channel conditions, thus balancing bandwidth capacity and power consumption
2Productivity
If high-energy transmission symbols are used frequently to increase bandwidth capacity, then transmission rate is improved, but signal quality deteriorates due to channel impairments
Solution Approach 1:
The patent changes the probability parameters of symbol selection to optimize signal quality. By adjusting the distribution parameters to use high-energy symbols less frequently and low-energy symbols more frequently, the system reduces the impact of channel impairments like noise and distortion, thereby improving signal quality while maintaining adequate bandwidth capacity through the recursive mapping approach
Solution Approach 2:
The patent implements feedback mechanisms where the receiver evaluates the quality of received symbols and feeds back channel state information to the transmitter. The transmitter uses this feedback to recursively adjust the constellation shaping parameters, determining the optimal number of high-energy symbols (n1) to transmit, thereby creating a closed-loop system that continuously optimizes signal quality based on actual channel conditions
Data Source
AI summary
A transmitter generates a set of transmission symbols corresponding to a set of information bits. Generating the set of transmission symbols includes: performing probabilistic constellation shaping to set, in the set of transmission symbols, a quantity n1 of transmission symbols having a maximum transmission symbol amplitude value. Performing of the probabilistic constellation shaping includes performing a recursive procedure to map the set of information bits to a set of amplitude indicators that corresponds to amplitudes of transmission symbols. The set of amplitude indicators includes n1 amplitude indicators set to indicate the maximum transmission symbol amplitude value.