QC LDPC Rate Matching with Lifting Value Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wireless communication systems, particularly in LTE, face challenges with high error rates and complexity in turbo codes, which limit their performance and efficiency, especially in next-generation communication systems like 5G URLLC that require low error rates and rapid data transmission.
Innovation Solution
A quasi-cyclic low-density parity-check (QC LDPC) code rate matching method is developed, which involves selecting a minimum lifting value to generate a parity check matrix, encoding information blocks, and using a circular buffer to transmit codewords, supporting various code block lengths and improving coding gain through retransmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If turbo code is used in LTE communication system, then error correction capability is improved, but complexity is increased and error floor occurs at high SNR
Solution Approach 1:
The patent changes the fundamental parameters of the coding scheme by adopting LDPC code instead of turbo code, with specific focus on modifying the lifting value parameter. By dynamically selecting lifting values from a set of predetermined values based on code block length, the system achieves better error correction performance while controlling complexity through structured parity check matrices.
Solution Approach 2:
The patent introduces dynamic selection of lifting values based on code block length requirements. The lifting value is chosen from a set of predetermined values according to the specific communication scenario, allowing the system to adapt its coding parameters dynamically to optimize both performance and complexity for different transmission conditions.
2Reliability
If code length is increased to reduce error rate, then reliability is improved, but transmission delay is increased
Solution Approach 1:
The patent segments the coding process by using different lifting values for different code block lengths. This segmentation allows the system to use appropriate code lengths for different transmission requirements, avoiding unnecessary transmission delay while maintaining required reliability levels through optimized code block sizing and lifting value selection.
Solution Approach 2:
By changing the lifting value parameter based on code block length, the patent enables flexible adjustment of code rate and code block size. This parameter adaptation allows the system to achieve target error rates with minimal transmission delay by selecting optimal code parameters for each specific transmission scenario.
3Adaptability or versatility
If lifting value is increased to support various code block lengths, then adaptability is improved, but device complexity is increased
Solution Approach 1:
The patent applies preliminary action by pre-defining a set of lifting values before actual coding operations. These predetermined lifting values are stored and selected based on code block length requirements, eliminating the need for complex real-time calculations and reducing device complexity while maintaining adaptability to various code block lengths.
Solution Approach 2:
The patent manages complexity by discretizing the lifting value parameter into a finite set of predetermined values. This parameter quantization allows the system to support various code block lengths through simple selection from the predefined set, rather than requiring continuous parameter adjustment or complex matrix generation algorithms.
Data Source
AI summary
A quasi-cyclic low density parity check (QC LDPC) code rate matching method is disclosed. According to the rate matching method in the present disclosure, the minimum lifting value can be selected from among lifting values by which a codeword longer than a target code block can be generated. A coding gain through retransmission can be acquired by generating the codeword that is longer than the target code block. In addition, by selecting a lifting value of a proper magnitude, rate matching for information bit sequences of various lengths can be performed.