Punctured LDPC Retransmission for A-MPDU Joint Decoding
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Solution Overview
Problem
Existing wireless communications systems lack an efficient retransmission mechanism for improving transmission reliability and efficiency, particularly in next-generation WLAN systems.
Innovation Solution
A retransmitted data sending method and apparatus that utilize a punctured LDPC codeword based on the A-MPDU structure, allowing for combined decoding or joint decoding at the receive end to enhance transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retransmission mechanism is introduced to improve transmission reliability, then the reliability of wireless communication is improved, but the device complexity and system overhead increase
Solution Approach 1:
The patent segments the A-MPDU into multiple A-MPDU subframes, each containing one or more MPDUs. This segmentation allows selective retransmission of specific subframes or MPDUs that failed to decode, rather than retransmitting the entire A-MPDU. The receive end maintains a buffer to store soft information of previously received subframes and performs combined decoding with retransmitted subframes, thereby improving reliability while reducing the complexity of full retransmission.
Solution Approach 2:
The receive end pre-stores soft information (LLR values) of previously received A-MPDU subframes in a buffer before retransmission occurs. When a retransmitted subframe is received, the receive end combines it with the pre-stored soft information to perform joint decoding. This preliminary action enables efficient retransmission processing without requiring complex real-time decision-making, thus improving reliability while managing system complexity.
2Reliability
If retransmission with buffer storage is implemented to improve decoding success rate, then the decoding success rate is improved, but the loss of time due to buffering and combined decoding increases
Solution Approach 1:
The patent implements partial retransmission by allowing the transmit end to retransmit only specific A-MPDU subframes or individual MPDUs that failed to decode, rather than retransmitting the entire A-MPDU. The receive end performs combined decoding only for the retransmitted subframes with their corresponding pre-stored soft information. This partial action reduces the time required for buffering and decoding compared to full retransmission, while still improving the decoding success rate for the critical failed portions.
3Productivity
If punctured LDPC codewords are used for retransmission to reduce overhead, then the transmission efficiency is improved, but the manufacturing precision of the coding scheme increases
Solution Approach 1:
The patent employs punctured LDPC codewords for retransmission, where certain parity bits are removed (punctured) from the original LDPC codeword to reduce retransmission overhead. The transmit end applies different puncturing patterns to create varied retransmission versions, and the receive end uses corresponding puncturing information to correctly decode the punctured codewords by combining them with pre-stored soft information. This parameter change (puncturing) improves transmission efficiency while the standardized puncturing schemes keep the coding complexity manageable.
Data Source
AI summary
This application discloses a retransmitted data sending method, a retransmitted data receiving method, and a related apparatus, and relates to the field of communications technologies. In this solution, a transmit end generates a retransmitted codeword based on information bits of each codeword corresponding to an incorrect MPDU, where the retransmitted codeword includes a codeword having some of information bits included in the incorrect MPDU. For the codeword having some of information bits included in the incorrect MPDU, the transmit end punctures a correctly received information bit in the codeword, and then sends the information bit. In this way, a receive end may directly perform combined decoding or joint decoding on an LLR of a codeword of a retransmitted MPDU and an LLR of a codeword of an MPDU that is incorrectly received last time. This improves transmission efficiency and transmission reliability.