LDPC Rate Matching with Boundary Adjustment for Small Packets
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Solution Overview
Problem
In wireless communication systems, particularly for small packet sizes, the puncturing ratio of LDPC codewords exceeds a threshold, leading to reduced reliability due to insufficient parity bits for error correction, which affects the receiver's ability to detect and correct errors.
Innovation Solution
Adjusting the physical layer payload or coded bits boundary by adding symbols or symbol fractions to reduce the puncturing ratio, either by setting it to a target value or eliminating puncturing altogether, and incorporating pre-FEC padding bits to enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If puncturing is applied to LDPC codewords to fit packet size constraints, then packet size requirements are met, but reliability decreases due to insufficient parity bits for error correction
Solution Approach 1:
The patent adjusts the physical layer payload boundary or coded bits boundary by adding symbols or symbol fractions to change the effective packet size parameters. This allows the LDPC codeword to maintain sufficient parity bits while still meeting the required packet size constraints, thereby resolving the contradiction between packet size requirements and error correction capability
Solution Approach 2:
The patent introduces an additional dimension by incorporating pre-FEC padding bits before channel encoding. This extra dimension provides additional redundancy that compensates for the puncturing applied to fit packet size constraints, maintaining reliability while meeting size requirements
2Reliability
If puncturing ratio is reduced to target value or zero by adjusting boundary, then reliability improves with sufficient parity bits, but packet structure complexity increases
Solution Approach 1:
The patent performs preliminary actions by adding symbols or symbol fractions to adjust the physical layer payload boundary before LDPC encoding. It also adds pre-FEC padding bits in advance. These preliminary adjustments ensure that the final puncturing ratio is reduced to the target value or zero, improving reliability while managing complexity through structured advance planning
Solution Approach 2:
The patent introduces pre-FEC padding bits as an intermediary element between the data and the channel encoding process. This intermediary provides additional redundancy that facilitates error correction while maintaining a structured packet format, balancing reliability improvement with structural organization
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. The method may include a first wireless device generating one or more low density parity check (LDPC) codewords and adding one or more symbols or one or more symbol fractions to adjust a first boundary of a packet such that a puncturing ratio associated with the one or more LDPC codewords is reduced or set to zero. In some examples, the first boundary may specify a first number of symbols of the packet allocated for the one or more LDPC codewords. Further, the first wireless device may transmit, to a second wireless device, the packet comprising the one or more LDPC codewords based on the adjusted first boundary.