Transport Block Sizing With PAS and LDPC for 5G Spectral Efficiency
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Solution Overview
Problem
The existing 5G communication systems face inefficiencies in spectral efficiency due to the use of high-order quadrature amplitude modulation (QAM) constellations, where channel coding and modulation schemes output constellation points with equal probabilities, leading to suboptimal performance.
Innovation Solution
Implementing probabilistic amplitude shaping (PAS) combined with low-density parity-check (LDPC) codes to encode information bits into modulation sequences, ensuring different constellation points are output with varying probabilities, and adjusting channel coding and modulation schemes to align with target code rates determined by channel quality indicator (CQI) reports and modulation and coding scheme (MCS) indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-order QAM constellations are used with equal-probability channel coding, then data transmission capacity increases, but spectral efficiency deteriorates due to suboptimal performance
Solution Approach 1:
The patent applies probabilistic amplitude shaping (PAS) to change the probability distribution parameters of constellation points in high-order QAM modulations. Instead of equal probabilities, more probable amplitude levels are assigned to inner constellation points and less probable levels to outer points, optimizing the mismatch between channel capacity and modulation scheme to achieve near-Shannon-limit spectral efficiency
Solution Approach 2:
The patent implements different probability assignments for different amplitude levels within the QAM constellation. Each amplitude level is assigned a specific probability based on its position in the constellation diagram, creating local quality variations that optimize overall system performance by matching the channel's information-carrying capacity at different signal levels
2Reliability
If probabilistic amplitude shaping is implemented to optimize spectral efficiency, then coding gains up to 2 dB are achieved, but system complexity increases due to additional coding and modulation scheme adjustments
Solution Approach 1:
The patent performs preliminary probabilistic shaping of the information bits before channel encoding. The bit sequence is pre-processed to assign different probabilities to different bits, which simplifies the subsequent channel coding and modulation processes by preparing the data in an optimal format for the given channel conditions
Solution Approach 2:
The patent utilizes channel quality indicator (CQI) reports and modulation and coding scheme (MCS) indications as feedback mechanisms to dynamically adjust the probabilistic amplitude shaping parameters. This feedback loop allows the system to adapt to changing channel conditions and maintain optimal performance while managing complexity through standardized feedback procedures
3Productivity
If channel coding and modulation schemes are adjusted to align with target code rates from CQI reports, then spectral efficiency improves, but processing complexity increases
Solution Approach 1:
The patent integrates probabilistic amplitude shaping with standard 5G NR channel coding schemes (LDPC and polar codes) and modulation schemes (QPSK, 16QAM, 64QAM, 256QAM). This universal approach allows the same shaping mechanism to work across different coding and modulation schemes, reducing overall processing complexity through a unified framework rather than separate optimized solutions for each scheme
Data Source
AI summary
The present application relates to methods, systems, and devices related to digital wireless communication, and more specifically, to techniques related to determining a transport block size. In one exemplary aspect, a method for wireless communication is disclosed. The method includes receiving, by a terminal, a first message that identifies a first coding rate and a second coding rate. The method also includes performing, by the terminal, a first operation relating to a first coding operation and using the first coding rate. The method also includes performing, by the terminal, a second operation relating to a second coding operation and using the second coding rate. The method also includes transmitting or receiving, by the terminal, a second message using information related to the first operation and/or the second operation.