Layered LDPC Decoding With Reduced Syndrome Checks
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Solution Overview
Problem
Current LTE turbo codes exhibit limited performance improvement beyond a certain signal-to-noise ratio, leading to high error rates and increased complexity, which results in unnecessary retransmissions and latency issues in wireless communication systems, particularly in future-generation communication systems requiring faster data transmission and reception.
Innovation Solution
A method for layered decoding of low-density parity-check (LDPC) codes is introduced, which calculates log likelihood values and iteratively updates variable and check nodes based on a parity check matrix, using syndrome checks to determine successful decoding, thereby reducing power consumption and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LTE turbo code is used, then communication service is provided, but error rate remains high and complexity increases beyond predetermined SNR region
Solution Approach 1:
The patent changes the fundamental coding parameters by transitioning from turbo code structure to LDPC code structure with specific parity check matrices designed for different code rates. This parameter change enables the system to achieve lower error rates while controlling complexity through the structured nature of LDPC codes, particularly using quasi-cyclic LDPC codes that allow efficient implementation.
2Reliability
If code complexity is increased to lower error rate, then reliability improves, but overhead and latency increase
Solution Approach 1:
The patent segments the coding scheme into different LDPC code rates (e.g., 1/3, 2/3, 3/4, 4/5, 5/6) with optimized parity check matrices for each segment. This segmentation allows the system to select the appropriate code rate and complexity level based on channel conditions, achieving low error rates without unnecessarily increasing latency by using only the required complexity level.
Solution Approach 2:
The patent implements dynamic code rate selection capability, allowing the system to adaptively choose between different LDPC code rates based on channel quality and service requirements. This dynamic adjustment enables the system to maintain low error rates while minimizing latency by selecting lower complexity codes when channel conditions permit.
3Reliability
If conventional LDPC decoding is used, then decoding is performed, but power consumption and latency are high due to excessive memory reads
Solution Approach 1:
The patent extracts and utilizes the structured properties of quasi-cyclic LDPC codes, specifically the repetitive patterns in the parity check matrix, to reduce the number of memory reads required during decoding. By exploiting this structure, the decoder can perform syndrome checks and iterative decoding with fewer memory accesses, directly reducing power consumption while maintaining decoding accuracy.
Data Source
AI summary
An improved layered decoding method for a low density parity check (LDPC) code and a device therefor are disclosed. Disclosed is the layered decoding method for an LDPC code, capable of determining whether decoding is successful by performing a syndrome check on each check node at every variable node update. In addition, the syndrome check can be performed by using reduced variable nodes, thereby reducing decoding power consumption and decoding time consumption.