LDPC Generator Sub-Matrices for Adaptive Punctured Codewords
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Solution Overview
Problem
Existing LDPC code encoders are complex and require modification of decoders for rate adaptation, leading to high power consumption and inefficiency in adapting to changing wireless channel conditions.
Innovation Solution
A method and device that generate punctured code words by reducing the number of rows in the generator matrix to achieve a compatible coding rate, using a single mother code to produce child codes with lower performance but simpler implementation, and allowing incremental redundancy in hybrid ARQ schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple puncturing method is used to generate higher rate codes, then the implementation is simpler, but the complete codeword has to be generated each time leading to higher power consumption
Solution Approach 1:
The generator matrix is segmented into multiple sub-matrices, where each sub-matrix corresponds to a specific coding rate. Instead of generating the complete codeword and then puncturing, the system directly selects and uses only the required sub-matrix for the current transmission, segmenting the encoding process to avoid unnecessary computations and reduce power consumption.
Solution Approach 2:
The generator matrix is pre-organized into sub-matrices corresponding to different coding rates before transmission begins. This preliminary structuring allows the transmitter to directly select the appropriate sub-matrix based on channel conditions without performing full encoding and subsequent puncturing operations, thereby reducing real-time computational complexity and power consumption.
2Adaptability or versatility
If rate adaptation is performed using puncturing and repetition in existing systems, then the coding rate can be adapted, but the encoder complexity increases and decoder modification is required
Solution Approach 1:
The system uses a single universal generator matrix that contains sub-matrices for multiple coding rates. This universal structure allows the encoder to adapt to different coding rate requirements without requiring separate encoders or modifying the decoder architecture. The same decoder can process codewords generated with different sub-matrices, achieving multi-functionality without increasing device complexity.
Solution Approach 2:
The system dynamically selects which sub-matrix to use based on real-time channel conditions and transmission requirements. This dynamic selection capability allows flexible rate adaptation while maintaining a fixed, simple encoder structure. The generator matrix sub-matrices are designed to be compatible with a single decoder implementation, enabling adaptive coding without increasing overall system complexity.
Data Source
AI summary
The method and device include determining by removing N−N, rows from an original generator matrix (G) defining the LDPC code and having N rows and N−M columns for obtaining a generator sub-matrix (G1) having N−M columns and N1 rows. The method also includes delivering by receiving an input data vector of size N−M and multiplying the input vector with the generator sub-matrix for obtaining the punctured encoded code word.