Joint Probabilistic Shaping for Higher-Order Modulation Constellations

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Solution Overview

Problem

Existing wireless communication systems face inefficiencies in modulating data into modulation constellations, particularly for higher-order modulations, as they often use uniform distributions that do not maximize transmission capacity and spectral efficiency.

Innovation Solution

Implementing joint probabilistic shaping techniques for multiple bits per modulation constellation, where a transmitting device shapes information bits using masking bits determined by a joint linear code, and the receiving device decodes these bits using indicated masking bits to achieve non-uniform distributions, enhancing transmission capacity and spectral efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If uniform distribution is used for modulation constellations, then implementation is simple, but transmission capacity and spectral efficiency are not maximized

Engineering Contradiction:

Improvetransmission capacityVSAvoidshaping complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by transitioning from uniform distribution to non-uniform probabilistic distribution of constellation points. The system modifies the probability parameters of different constellation points based on their distances from the origin, allocating higher probabilities to closer points and lower probabilities to farther points, thereby maximizing spectral efficiency while managing complexity through structured probability assignment

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements dynamic probabilistic shaping where the probability distribution of modulation symbols is adaptively adjusted based on channel conditions and transmission requirements. The shaping bits dynamically control the probability assignment to different constellation points, enabling the system to optimize transmission capacity in real-time while maintaining manageable complexity through structured control

Inventive Principle:

Principle #15Dynamics

2Productivity

If higher-order modulations are used, then spectral efficiency increases, but reliability decreases

Engineering Contradiction:

Improvespectral efficiencyVSAvoidtransmission reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the probability assignment for different local regions of the modulation constellation. Constellation points closer to the origin are assigned higher probabilities while those farther away are assigned lower probabilities. This local differentiation optimizes the balance between spectral efficiency and reliability by ensuring more reliable transmission for less reliable constellation regions

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system performs preliminary probabilistic shaping before modulation by pre-determining the probability distribution for constellation points based on their geometric properties. This preliminary action prepares the bit sequences with optimized probability patterns that will result in non-uniform constellation distributions, thereby enhancing reliability before the actual transmission occurs

Inventive Principle:

Principle #10Preliminary action

3Productivity

If probabilistic shaping is applied to multiple bits per constellation, then spectral efficiency improves, but implementation complexity increases

Engineering Contradiction:

Improvespectral efficiencyVSAvoidshaping implementation complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the bit sequences into groups and applying probabilistic shaping to multiple bits per constellation point simultaneously. The system segments the information bits and processes them in structured groups, applying the probability distribution pattern to multiple bits at once, thereby achieving higher spectral efficiency while managing implementation complexity through systematic processing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements universality by creating a generalizable probabilistic shaping framework that can be applied to different modulation orders and channel conditions. The same core principles of non-uniform probability distribution and structured bit processing can be universally applied across various scenarios, reducing implementation complexity through reusability and adaptability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250330265A1Techniques for joint probabilistic shaping of multiple bits per modulation constellation

Publication Date: 2025.10.23 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described that provide for a probabilistic shaping framework for higher-order modulations in which probabilistic shaping of modulation constellations is performed for two or more bits per constellation. A transmitting device may shape a set of information bits using a set of masking bits. The transmitting device may encode, shape, modulate, and transmit the set of information bits to a receiving device, and the receiving device may demodulate, deshape, and decode the received information bits. The transmitting device may transmit a set of shaping bits, which may be indicative of the set of masking bits. The receiving device may use the set of shaping bits to generate the set of masking bits, and may use the set of masking bits to deshape the information bits. Further, the transmitting device may provide an indication of a quantity of shaped bits per modulation symbol.