64800-Bit LDPC Encoder Using PCM Segmentation for Robust Reception
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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 7/15 is developed, utilizing an LDPC encoding technique that efficiently performs encoding using a sequence derived from a parity check matrix, specifically dividing the systematic and parity parts by a circulant permutation matrix size of 360, to facilitate robust reception and frequency reuse in wireless channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a new LDPC codeword with length 64800 and code rate 7/15 is designed, then reception robustness and spectrum efficiency are improved, but device complexity and encoding complexity increase
Solution Approach 1:
The LDPC codeword is divided into a systematic part (30240 bits) and a parity part (33480 bits). The parity check matrix is segmented into multiple blocks, with different structures applied to different segments. This segmentation allows the encoder to handle large-scale coding through modular operations, reducing implementation complexity while maintaining the specified code rate of 7/15 and length of 64800.
Solution Approach 2:
The invention employs a specific parity check matrix structure with carefully selected parameters: code length N=64800, information length K=30240, giving code rate R=K/N=7/15. The girth parameter is set to 6, and the matrix is constructed with specific circulant permutation patterns. These parameter optimizations ensure reception robustness approaches the Shannon limit while enabling efficient encoding implementation.
2Loss of energy
If frequency reuse is enabled to eliminate white spaces, then spectrum efficiency is improved, but co-channel interference increases
Solution Approach 1:
The invention uses a specifically designed LDPC code with rate 7/15 that provides strong error correction capability against co-channel interference. The code structure with girth 6 and optimized parity check matrix enables reliable reception in interference environments, allowing aggressive frequency reuse patterns that eliminate white spaces. The code acts as a robust protector that enables spectrum efficiency improvement despite the presence of co-channel interference.
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 7/15. 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).