Adaptive LDPC Base Matrix Switching for Variable 5G Code Rates
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Solution Overview
Problem
Existing LDPC code technologies face challenges in supporting various input lengths and code rates, particularly in 5G communication systems, where noise, fading, and inter-symbol interference degrade link performance, and existing lifting methods limit the flexibility of LDPC code design.
Innovation Solution
The proposed method designs LDPC codes using a lifting method that considers trapping set characteristics, allowing for the selection of either a first or second base matrix based on transport block size and code rate, enabling flexible encoding and decoding across various lengths and rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed lifting method is used for LDPC code design, then the encoding/decoding process is simplified, but the code cannot support various input lengths and code rates
Solution Approach 1:
The patent implements dynamic selection between a first base matrix and a second base matrix based on transport block size and code rate requirements. The system transitions from a static fixed lifting method to a dynamic adaptive method where the appropriate base matrix is selected according to current communication conditions, enabling support for various input lengths and code rates while maintaining manageable complexity through predefined selection criteria
Solution Approach 2:
The patent changes the parameters of the LDPC code design by introducing multiple base matrices with different lifting configurations. Instead of using a single fixed lifting method, the system varies the base matrix parameters (first base matrix for certain transport block sizes and code rates, second base matrix for others) to optimize performance for different communication scenarios, thereby achieving versatility across various input lengths and code rates
2Reliability
If existing LDPC code technologies are used, then implementation is straightforward, but reliability is degraded by noise, fading, and inter-symbol interference
Solution Approach 1:
The patent applies preliminary action by pre-designing and pre-configuring multiple base matrices with optimized lifting methods that account for trapping set characteristics. Instead of dealing with noise and interference issues during real-time operation, the system prepares multiple pre-optimized code configurations in advance, selecting the appropriate pre-designed base matrix based on current conditions, thereby improving reliability without adding real-time computational complexity
Solution Approach 2:
The patent creates multiple copies of base matrices (first base matrix and second base matrix) with different lifting configurations optimized for different conditions. Rather than attempting to handle all noise and interference scenarios with a single complex algorithm, the system creates multiple simplified copies of the base matrix structure, each optimized for specific trapping set characteristics and communication conditions, then selects the appropriate copy based on current requirements
Data Source
AI summary
This disclosure relates to a 5G or pre-5G communication system for supporting a higher data transfer rate than a 4G communication system such as LTE. The present invention relates to a method for encoding and decoding a channel in a communication or broadcasting system, comprising the steps of determining an input bit size (CBS), determining a code rate (R), determining a size (Z) of a block, comparing the determined CBS and code rate with predetermined reference values, determining an LDPC sequence to perform LDPC encoding according to the comparison result, and performing LDPC encoding and decoding on the basis of the LDPC sequence and the block size. Further, the present invention comprises the steps of determining a code rate (R) indicated by a modulation and coding scheme (MCS) index, determining a transport block size, and determining either a first basic matrix or a second basic matrix as a basic matrix on the basis of the transport block size and the code rate.