LDPC Packet Encoding With Power-of-Two Lifting for Variable Sizes
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Solution Overview
Problem
There is a need for techniques that support efficient Low Density Parity Check (LDPC) encoding and decoding of packets of varying sizes, as existing LDPC codes are typically designed for specific packet sizes and struggle to accommodate packets of different sizes effectively.
Innovation Solution
The use of a set of base parity check matrices of different dimensions and a set of lifting values of different powers of two allows for efficient LDPC encoding and decoding of packets of varying sizes, with the lifting process enabling efficient parallel encoding and decoding and reducing description complexity for large LDPC codes. Additionally, a single set of cyclic shift values for non-zero elements can be used to generate cyclic shift values for all other lifting values, simplifying the encoding and decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single LDPC code is designed for a specific packet size, then encoding and decoding performance is optimized for that size, but the code cannot efficiently accommodate packets of varying sizes
Solution Approach 1:
The patent applies universality by designing a single LDPC code structure that can handle multiple packet sizes through systematic puncturing and shortening operations. The base LDPC code is constructed with a specific structure that allows it to be adapted to different packet sizes by selectively removing or retaining certain bits, enabling one code to serve multiple functions across varying data lengths.
Solution Approach 2:
The patent utilizes parameter changes by modifying the effective code parameters (code rate, packet length) through puncturing and shortening operations. By changing these parameters dynamically based on the input packet size, the system maintains optimal encoding and decoding performance across different sizes without requiring separate codes for each size.
2Reliability
If multiple LDPC codes are designed for different packet sizes, then each code is optimized for its specific size, but the overall system complexity increases
Solution Approach 1:
Instead of maintaining multiple separate LDPC codes, the patent employs a universal base code that can be configured for different packet sizes through systematic modifications. This single universal code replaces what would otherwise require multiple specialized codes, reducing system complexity while maintaining optimized performance for each size through selective puncturing and shortening.
Solution Approach 2:
The patent applies segmentation by dividing the base LDPC code into manageable sections that can be selectively retained or removed. This segmentation allows the system to create different effective codes from a single base code by selecting specific segments to keep or puncture, thereby achieving size adaptation without storing multiple complete codes.
3Adaptability or versatility
If LDPC codes are designed to support variable packet sizes, then versatility is improved, but the description complexity and implementation overhead increase
Solution Approach 1:
The patent manages description complexity by systematically changing code parameters through standardized puncturing and shortening patterns. Rather than requiring complex descriptions for each possible packet size, the system uses a unified description of the base code combined with simple parameter adjustment rules that define how to modify the base code for different sizes, significantly reducing the overall description burden.
Data Source
AI summary
Techniques to support low density parity check (LDPC) encoding and decoding are described. An apparatus includes at least one processor and a memory coupled to the at least one processor. The at least one processor is configured to encode or decode a packet based on a base parity check matrix and a set of lifting values. In a particular embodiment, the set of lifting values is limited to lifting values that are each a different power of two. The memory is configured to store parameters associated with the base parity check matrix.