LDPC Parity Check Matrix Structure for Negative-SNR 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 space,' which necessitates a transmission technology that can operate in negative Signal to Noise Ratio (SNR) environments and improve error correction for terrestrial cloud broadcast signals.
Innovation Solution
The development of an LDPC encoder and decoder using 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 a dual diagonal matrix, identity matrix, and zero matrix to encode and decode input information efficiently in a negative SNR environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terrestrial TV broadcasting uses conventional frequency allocation, then service coverage is provided, but co-channel interference occurs and spectrum efficiency deteriorates due to white space
Solution Approach 1:
The patent segments the frequency usage by implementing a single frequency network where multiple transmitters use the same frequency but are coordinated through centralized control. This segmentation allows frequency reuse across different geographic areas while maintaining service coverage, eliminating white space and improving spectrum efficiency without causing co-channel interference.
2Productivity
If terrestrial cloud broadcast operates in overlapping signal areas, then frequency reuse is improved, but signal demodulation becomes difficult due to co-channel interference
Solution Approach 1:
The patent implements feedback mechanisms where the central controller receives signal quality information from receivers in overlapping areas and adjusts transmission parameters accordingly. This feedback loop enables the system to maintain reliable signal demodulation while operating in frequency-reused environments with co-channel interference, allowing effective terrestrial cloud broadcast operation.
3Productivity
If LDPC code uses higher code rate, then transmission capacity increases, but error correction performance deteriorates in negative SNR environment
Solution Approach 1:
The patent employs dynamic code rate adaptation where the LDPC code rate is adjusted based on channel conditions. In negative SNR environments, the system dynamically selects lower code rates to maintain error correction performance, while transitioning to higher code rates when channel conditions improve, thus optimizing both transmission capacity and reliability adaptively.
Solution Approach 2:
The patent changes key parameters of the LDPC code including code rate, block length, and parity check matrix structure to optimize performance for terrestrial cloud broadcast in negative SNR environments. These parameter adjustments enable the system to achieve reliable error correction while maintaining adequate transmission capacity for the specific broadcast application.
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.