LDPC HARQ Parity Puncturing for Flexible Code Rates
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Solution Overview
Problem
Conventional LDPC code-based IR-HARQ schemes face performance degradation due to puncturing and lack support for various code rates, as puncturing is performed only in a block unit, limiting their effectiveness.
Innovation Solution
The method performs puncturing processes in both block and bit units for the parity region of an LDPC code, allowing for various code rates and prioritizing transmission based on importance, with block and bit shuffling to achieve channel interleaving effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If puncturing is performed only in a block unit for LDPC code-based IR-HARQ, then the implementation is simple, but various code rates cannot be supported and performance degradation occurs
Solution Approach 1:
The parity region of the LDPC code is divided into multiple sub-blocks, and puncturing can be performed at both block and bit levels within these sub-blocks. This segmentation allows flexible selection of code rates by controlling which sub-blocks and bits are punctured, thereby supporting various code rates while maintaining implementation feasibility.
Solution Approach 2:
The puncturing pattern is made dynamic by introducing transmission priority classification for different parity bit groups. The system can adaptively select which parity bits to transmit or puncture based on channel conditions and required code rates, enabling flexible adaptation to different code rate requirements rather than using a fixed block-unit puncturing approach.
2Ease of manufacture
If conventional block-unit puncturing is used in LDPC IR-HARQ, then the system is easy to implement, but performance degradation due to puncturing cannot be minimized
Solution Approach 1:
Different priority levels are assigned to different groups of parity bits based on their importance to decoding performance. Critical parity bits with higher priority are transmitted first, while less critical bits are punctured. This local differentiation of quality ensures that the most important information is preserved while allowing selective puncturing of less critical bits, thereby minimizing performance degradation.
Solution Approach 2:
The system pre-classifies parity bits into different priority groups before transmission based on their importance to decoding. This preliminary classification allows the receiver to efficiently reconstruct the original codeword by combining received packets with different priority levels, improving decoding performance compared to random or uniform puncturing approaches.
3Ease of manufacture
If parity bits are transmitted without classification by importance, then the transmission process is simple, but channel interleaving effect cannot be achieved
Solution Approach 1:
Parity bits are segmented into multiple groups based on their transmission priority. Each group is shuffled separately using different patterns, and then transmitted in a prioritized sequence. This segmentation and differential shuffling creates an interleaving effect that protects against burst errors while maintaining a relatively simple transmission structure.
Solution Approach 2:
The shuffling pattern is made dynamic and adaptive based on the priority classification of parity bits. Different shuffling patterns are applied to different priority groups, creating a dynamic interleaving structure that adapts to the importance of different parity bits. This dynamic approach achieves channel interleaving effects without requiring complex reconfiguration.
Data Source
AI summary
A transmission method based on a Hybrid Automatic Repeat Request (HARQ) scheme for in a communication system. A codeword is generated using a Low Density Parity Check (LDPC) code. Parity bits of the codeword are classified on a basis of a transmission priority. Parity bits with an identical transmission priority are grouped. An information bit group of the codeword and parity bit groups with the identical transmission priority are shuffled in a predefined pattern. A packet is generated from the shuffled information bit group and the shuffled parity bit groups based on the transmission priority. The generated packet is retransmitted in response to a retransmission request. The transmission method can obtain the effect of channel interleaving by setting a transmission priority according to importance of puncturing target blocks, shuffling blocks with the same priority, and shuffling and transmitting bits configuring each block.