LDPC Convolutional Encoding for Variable-Length Packet Transmission
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Solution Overview
Problem
Current LDPC codes face challenges in efficiently encoding variable-length data due to the need for redundant bits when the number of transmission data bits is not an integral multiple of the code block length, leading to decreased data transmission efficiency, particularly in packet communication systems.
Innovation Solution
Designing an LDPC-CC with a smaller protograph size by creating a convolutional code and modifying the parity check matrix to include '1' in approximate lower triangular or upper trapezoidal matrices, which allows for improved received quality and reduced redundant bits through BP decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed-length LDPC code block is used to encode variable-length data packets, then error correction capability is maintained, but redundant bits must be transmitted when the data length is not an integral multiple of the code block length, decreasing data transmission efficiency
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-length block codes to variable-length convolutional codes. The LDPC-CC encoder processes information sequences of arbitrary length without requiring fixed block segmentation, allowing the code length to dynamically adapt to the input data size. This eliminates the need for padding operations and reduces redundant bit transmission while maintaining error correction capability through the convolutional structure with shift registers and modulo-2 adders.
2Stability of the object's composition
If padding processing is performed to match variable-length data to fixed-length code blocks, then code structure integrity is preserved, but redundant sequence transmission occurs, wasting bandwidth
Solution Approach 1:
The patent extracts and eliminates the padding operation from the encoding process. By using LDPC-CC with arbitrary-length input capability, the system removes the unnecessary padding bits that were previously added to fill fixed-length blocks. The convolutional code structure naturally accommodates variable-length inputs, extracting only the essential data bits for transmission without adding redundant padding sequences.
3Productivity
If puncturing processing is applied to reduce redundant bits in fixed-length blocks, then data transmission efficiency improves, but coding rate changes and error correction capability is compromised
Solution Approach 1:
The patent applies dynamics by using LDPC-CC to naturally adapt code length to data length, eliminating the need for puncturing operations. The convolutional structure with configurable shift register lengths and modulo-2 adders allows the system to achieve variable-length encoding without removing bits from the code sequence. This maintains the intended coding rate and error correction capability while improving transmission efficiency through direct variable-length processing.
Data Source
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AI summary
A low-density parity check convolution code (LDPC-CC) is made, and a signal sequence is sent after subjected to an error-correcting encodement using the low-density parity check convolution code. In this case, a low-density parity check code of a time-variant period (3g) is created by linear operations of first to 3g-th (letter g designates a positive integer) parity check polynomials and input data.