LDPC Parity Check Matrix for Negative-SNR Cloud Broadcast
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Solution Overview
Problem
Current terrestrial TV broadcasting systems face co-channel interference, leading to inefficient spectrum reuse and the occurrence of 'white spaces,' which necessitate a robust error correction method capable of operating in negative Signal to Noise Ratio (SNR) environments, especially for terrestrial cloud broadcast systems.
Innovation Solution
The development of an LDPC encoder and decoder that utilizes a parity check matrix structure combining a first parity check matrix for a higher code rate with a second parity check matrix for a lower code rate, incorporating zero, identity, and dual diagonal matrices, to encode and decode input information efficiently in negative SNR conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error correction codes are used in terrestrial TV broadcasting, then the system can operate with standard coding schemes, but the system cannot achieve reliable communication in negative SNR environments and cannot enable frequency reuse within three times service coverage
Solution Approach 1:
The patent changes the fundamental parameters of the error correction code by using LDPC codes with specifically designed parity check matrices that have different structures (cyclic, quasi-cyclic, and non-cyclic) optimized for negative SNR environments. The code rate and block length are also adjusted to achieve reliable communication where conventional codes fail
2Productivity
If frequency reuse is implemented within three times service coverage, then spectrum efficiency is improved, but co-channel interference causes communication reliability to deteriorate
Solution Approach 1:
The patent converts the harmful effect of co-channel interference into a beneficial outcome by designing LDPC codes that can actually improve performance in the presence of interference. The specially structured parity check matrices are designed to handle the interference patterns that arise from frequency reuse, turning the previously harmful interference into a manageable condition that enables spectrum efficiency improvement
3Reliability
If existing LDPC codes are used for terrestrial cloud broadcast, then the system can provide error correction, but the codes cannot operate effectively in negative SNR environments required for cloud broadcast
Solution Approach 1:
The patent applies local quality by designing parity check matrices with specific local structures (cyclic, quasi-cyclic, non-cyclic) that are optimized for the particular conditions of terrestrial cloud broadcast. Each matrix type has specific properties that make it suitable for certain aspects of negative SNR operation, allowing the system to maintain error correction functionality where existing codes fail
4Adaptability or versatility
If robust error correction is implemented for negative SNR operation, then adaptability to harsh environments is improved, but code complexity increases
Solution Approach 1:
The patent segments the error correction function into different LDPC code structures (cyclic, quasi-cyclic, non-cyclic) with specific parity check matrices for different code rates. This segmentation allows the system to select the appropriate code structure for the specific operating conditions, achieving robust negative SNR operation without unnecessarily increasing complexity for all cases
Data Source
AI summary
Provided is an LDPC (Low Density Parity Check) code for terrestrial cloud broadcast. A method of encoding input information based on an LDPC (Low Density Parity Check) includes receiving information and encoding the input information with an LDPC codeword using a parity check matrix, wherein the parity check matrix may have a structure obtained by combining a first parity check matrix for an LDPC code having a higher code rate than a reference value with a second parity check matrix for an LDPC code having a lower code rate than the reference value.