LDPC Encoder Structure for 64800-Length Broadcast Codewords
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Solution Overview
Problem
Current terrestrial TV broadcasting systems face co-channel interference issues, leading to white spaces where frequency reuse is not possible, resulting in deteriorated spectrum efficiency, and existing LDPC codes are not optimized for the DVB broadcast standard or specific LDPC encoding methods.
Innovation Solution
A new LDPC codeword of length 64800 with a code rate of 5/15 is developed, utilizing an LDPC encoding technique that efficiently generates codewords using a sequence corresponding to a parity check matrix, specifically designed for terrestrial cloud transmission, incorporating a systematic part, first parity part, and second parity part, with a circulant permutation matrix size of 360, to enhance reception robustness and spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terrestrial TV broadcasting uses current frequency allocation, then broadcasting coverage is achieved, but co-channel interference occurs and spectrum efficiency deteriorates due to white spaces
Solution Approach 1:
The patent applies parameter changes by optimizing the LDPC code structure with specific code rate (5/15) and length (64800), and by designing a tailored parity check matrix with specific circulant permutation patterns. These parameter optimizations enable the system to achieve both reliable reception in co-channel interference environments and improved spectrum efficiency through frequency reuse.
2Reliability
If LDPC code length is increased to improve error correction, then reception robustness improves, but encoding complexity and memory requirements increase
Solution Approach 1:
The patent segments the LDPC codeword into systematic part and parity part with specific lengths (21600 and 43200 respectively), and divides the parity check matrix into circulant permutation matrices of size 360×360. This segmentation allows efficient encoding through structured matrix operations while maintaining strong error correction capability for the 64800-length codeword.
Solution Approach 2:
The patent optimizes the balance between code length and complexity by selecting specific parameters: code length 64800, circulant permutation matrix size 360×360, and code rate 5/15. These parameter choices enable efficient implementation with reduced memory requirements while maintaining robust error correction performance.
3Reliability
If LDPC code is optimized for specific code rate and length, then performance approaches Shannon limit, but adaptability to different broadcast standards decreases
Solution Approach 1:
The patent designs an LDPC code with code rate 5/15 and length 64800 that can be universally applied across different terrestrial broadcast standards including DVB-T2 and ATSC 3.0. The structured parity check matrix with circulant permutation matrices provides a flexible framework that maintains optimal performance near the Shannon limit while being adaptable to various broadcast requirements.
Data Source
AI summary
A low density parity check (LDPC) encoder, an LDPC decoder, and an LDPC encoding method are disclosed. The LDPC encoder includes first memory, second memory, and a processor. The first memory stores an LDPC codeword having a length of 64800 and a code rate of 5/15. The second memory is initialized to 0. The processor generates the LDPC codeword corresponding to information bits by performing accumulation with respect to the second memory using a sequence corresponding to a parity check matrix (PCM).