LDPC Convolutional Coding for Variable-Length Packet Transmission
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Solution Overview
Problem
Current Low-Density Parity-Check (LDPC) codes face challenges in efficiently encoding variable-length data packets, leading to increased redundant bit transmission and decreased data transmission efficiency, particularly with large block sizes or protograph sizes, which is not effectively addressed by existing LDPC codes.
Innovation Solution
The development of a Low-Density Parity-Check Convolutional Code (LDPC-CC) with a smaller protograph size, utilizing parity check polynomials and a decoder configuration that includes Belief Propagation (BP) decoding, allows for efficient encoding and decoding of information sequences of arbitrary lengths, reducing redundant bits and improving received quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC block code with large block size is used, then error correction capability is improved, but redundant bit transmission increases and data transmission efficiency decreases
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-block LDPC codes to convolutional LDPC codes that can dynamically adapt to variable-length data packets. The encoder processes data continuously without fixed block boundaries, and the decoder uses a sliding window approach to maintain optimal error correction capability while adapting to changing packet lengths, thus resolving the contradiction between reliability and transmission efficiency.
Solution Approach 2:
The patent changes the fundamental parameter of code structure from block-based to convolutional-based. This parameter change allows the system to maintain high error correction capability through the inherent properties of convolutional codes (memory effect, continuous encoding) while eliminating the need for padding to fixed block sizes, thereby improving data transmission efficiency for variable-length packets.
2Adaptability or versatility
If padding processing is performed on transmission information sequence, then LDPC block code can be applied, but coding rate changes and redundant sequence transmission occurs
Solution Approach 1:
The patent extracts and eliminates the padding operation from the encoding process. By using convolutional LDPC codes, the system directly encodes variable-length packets without adding redundant padding bits, thus removing the source of redundant sequence transmission while maintaining compatibility with LDPC code structures through the convolutional encoding framework.
Solution Approach 2:
The patent implements dynamic encoding where the code structure adapts to the actual packet length. The convolutional encoder continuously processes incoming bits without requiring the data to be padded to a fixed block size, making the coding rate and redundancy dynamically matched to the actual information length, thereby eliminating unnecessary redundant bit transmission.
3Adaptability or versatility
If puncturing processing is performed on transmission information sequence, then LDPC block code can be applied, but coding rate changes and redundant sequence transmission occurs
Solution Approach 1:
The patent extracts and eliminates the puncturing operation from the encoding process. By using convolutional LDPC codes, the system directly encodes variable-length packets without requiring puncturing to achieve desired coding rates, thus removing the source of redundant sequence transmission while maintaining compatibility with LDPC code structures through the convolutional encoding framework.
Data Source
AI summary
A low-density parity check convolution code (LDPC-CC) is made, and a signal sequence is sent after being 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.