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 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, especially for small packet communication.
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 a fixed-length LDPC code block is used to encode variable-length transmission data, then error correction capability is improved, but data transmission efficiency deteriorates due to redundant bits from padding
Solution Approach 1:
The patent transitions from static fixed-length LDPC code blocks to dynamic variable-length LDPC convolutional codes. The encoder adapts the code length to match the actual transmission data length, eliminating the need for padding while maintaining error correction capability through convolutional encoding structure with shift registers and modulo-2 adders.
Solution Approach 2:
The patent changes the fundamental parameter of code block length from fixed to variable. By using LDPC-CC with arbitrary length information sequences, the system can encode data of any length without padding, directly resolving the efficiency loss caused by redundant bits in fixed-length schemes.
2Adaptability or versatility
If padding processing is performed to match LDPC code block length, then encoding compatibility is improved, but redundant sequence transmission increases
Solution Approach 1:
The patent extracts and eliminates the padding operation from the encoding process. By using LDPC-CC that natively supports variable-length inputs, the system removes the unnecessary padding step that previously added redundant bits, achieving both compatibility and efficiency simultaneously.
Solution Approach 2:
The system dynamically adjusts the code structure to match the input data length, eliminating the static padding requirement. The convolutional encoder processes data of any length directly, adapting the output code length to the input information sequence length without adding redundant padding bits.
3Adaptability or versatility
If puncturing processing is performed to adjust transmission information length, then data rate flexibility is improved, but coding rate changes occur
Solution Approach 1:
The patent creates a universal LDPC-CC encoder that handles all data lengths and coding rates through a single unified structure. The convolutional encoder with configurable memory length M and coding rate R=n/c can process any input length and maintain consistent coding rate, eliminating the need for puncturing-based rate adaptation.
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.