LDPC Codeword Signaling for Variable Wi‑Fi Packet Lengths
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Solution Overview
Problem
The introduction of longer LDPC code word lengths in next-generation Wi-Fi (802.11bn) necessitates updates to LDPC PPDU encoding processes to accommodate new code word lengths, particularly 1944×2, while avoiding performance degradation and efficiency loss due to excessive puncturing or shortening when packet sizes are small.
Innovation Solution
Implementing 2×LDPC codeword signaling methods, including updating PPDU encoding tables and signaling mechanisms to dynamically select between 1× and 2×LDPC codewords based on receiver capabilities and packet size, ensuring efficient use of LDPC code words without unnecessary puncturing or shortening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longer LDPC code word lengths (1944×2) are introduced to improve coding gain, then error correction capability is improved, but performance degradation occurs due to excessive puncturing or shortening when packet sizes are small
Solution Approach 1:
The patent implements dynamic selection between 1×LDPC and 2×LDPC code word lengths based on the number of available bits. When available bits exceed 2592, the system dynamically switches to 2×LDPC (3888 bits) for improved coding gain. When available bits are 2592 or fewer, the system dynamically selects 1×LDPC (1944 bits) to avoid excessive puncturing or shortening that would degrade performance. This dynamic adaptation resolves the contradiction by adjusting code word length according to actual transmission needs.
2Productivity
If 2×LDPC code words are used to increase data throughput, then productivity is improved, but loss of time occurs due to receiver preparation requirements
Solution Approach 1:
The patent incorporates signaling information in the preamble that indicates whether 2×LDPC code words will be used before the actual data transmission begins. This preliminary indication allows the receiver to prepare appropriate processing resources in advance. When 2×LDPC is signaled, the receiver can pre-allocate memory and processing capabilities, thereby reducing the effective preparation time penalty and enabling higher throughput without significant time loss.
3Adaptability or versatility
If LDPC PPDU encoding tables are updated to accommodate new code word lengths, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent segments the LDPC encoding capability into distinct modes: 1×LDPC (1944 bits) and 2×LDPC (3888 bits). Each mode has its own encoding parameters and processing requirements. By segmenting the capability this way, the system can selectively activate only the necessary encoding mode based on packet size, rather than maintaining complex logic to handle all possible code word lengths continuously. This segmentation reduces operational complexity while maintaining adaptability.
Data Source
AI summary
This disclosure describes systems, methods, and devices related to low-density parity-check (LDPC) code word encoding and signaling for LDPC code word encoding two or more LDPC code words each of a multiple of 1944 bits that is variable based on a number of available bits being greater than 2592 bits. A device may generate signaling of the LDPC code word length and generate a preamble that includes the signaling. The device may send the preamble followed by the LDPC code words of the code word length. The present disclosure therefore enables longer LDPC code word lengths than 1944 bits.