Probabilistic Shaping of Retransmissions for Better Decoding
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in improving decoding performance for retransmissions due to uniform probability distribution of modulation constellation symbols, which affects error correction and reliability.
Innovation Solution
The implementation of probabilistic shaping for error correction bits in retransmissions, allowing for a non-uniform probability distribution of modulation constellation symbols, enhancing the transmission and reception of messages by optimizing the mapping of bits to modulation symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform probability distribution of modulation constellation symbols is used, then the system is simple to implement, but decoding performance and error correction reliability deteriorate
Solution Approach 1:
The patent applies parameter changes by transitioning from a uniform probability distribution to a non-uniform probability distribution for modulation constellation symbols. Specifically, it uses probabilistic shaping to assign different probabilities to different constellation points, thereby optimizing the distribution to improve decoding performance and error correction reliability while managing system complexity.
2Reliability
If probabilistic shaping is applied to retransmissions, then error correction and decoding performance improve, but the complexity of transmission and reception processing increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing mapping tables that define the non-uniform probability distribution for modulation constellation symbols before transmission. This allows the transmitter to efficiently select constellation points based on pre-determined probabilities, and enables the receiver to use pre-computed lookup tables for decoding, thereby reducing real-time processing complexity while maintaining improved error correction performance.
Data Source
AI summary
An apparatus (e.g., a transmitter) may transmit a message and one or more retransmissions of the message in a wireless communication network. The message may include a codeword that includes information bits and error correction bits (e.g., parity bits). The one or more retransmissions may include error correction bits associated with the information bits. To improve the decoding performance at a receiver, the transmitter may apply probabilistic shaping to the one or more retransmissions. In some aspects, the apparatus transmits a first message including information bits and a first set of error correction bits associated with the information bits. The apparatus transmits at least a second message associated with the first message, wherein the second message includes a second set of error correction bits associated with the information bits and a set of probabilistic shaping bits for the second set of error correction bits.