LDPC Encoder Matrix Structure for Frequency-Reuse Broadcasting
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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 with a length of 64800 and a code rate of 7/15 is developed, using an LDPC encoding technique that efficiently performs encoding with a sequence derived from a parity check matrix, incorporating a systematic part, a dual diagonal matrix, and an identity matrix, optimized for terrestrial cloud transmission to mitigate co-channel interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current terrestrial TV broadcasting systems use conventional frequency allocation, then co-channel interference is avoided, but spectrum efficiency deteriorates due to white spaces where frequency reuse is not possible
Solution Approach 1:
The patent converts the harmful effect of co-channel interference into a beneficial feature by designing LDPC codes specifically optimized for cloud transmission scenarios where controlled interference and signal overlap are expected. The code structure transforms the previously harmful interference environment into an acceptable operating condition that enables frequency reuse.
Solution Approach 2:
The patent changes the parameters of the LDPC code (code length, code rate, parity check matrix structure) to optimize performance for cloud transmission. Specifically, it uses code length 64800 and code rate 7/15, with a specially designed parity check matrix that accounts for the interference characteristics of overlapping broadcast signals from different transmitters.
2Adaptability or versatility
If existing LDPC codes are used for terrestrial cloud transmission, then general encoding capability is maintained, but performance is not optimized for specific DVB broadcast standards and cloud transmission scenarios
Solution Approach 1:
The patent applies local quality by designing the parity check matrix with specific local structures (dual diagonal and identity matrix components) that are optimized for the particular requirements of DVB broadcast standards and cloud transmission. Rather than using a generic uniform structure, the matrix has specialized regions that address specific challenges of the transmission environment.
Solution Approach 2:
The LDPC codeword is segmented into a systematic part and a parity part, with the parity part further structured according to the parity check matrix composition. This segmentation allows different portions of the code to serve different functions: the systematic part carries information while the structured parity part provides error correction optimized for cloud transmission conditions.
3Productivity
If frequency reuse is implemented in terrestrial broadcasting, then spectrum efficiency improves, but co-channel interference increases requiring advanced error correction
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a robust LDPC code structure with specific parity check matrix design that anticipates and prepares for the expected level of co-channel interference in cloud transmission. The code is designed in advance to withstand the interference that will occur when frequencies are reused across overlapping broadcast areas.
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).