LDPC Encoder Sequence Design for Co-Channel Robust 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 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 a circulant permutation matrix, to facilitate robust reception and frequency reuse in wireless channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDPC codes are used for terrestrial broadcasting, then implementation is straightforward with existing standards, but co-channel interference causes white spaces and deteriorated spectrum efficiency
Solution Approach 1:
The patent applies parameter changes by designing an LDPC code with specific parameters (code length 64800, code rate 7/15, and a specifically constructed parity check matrix) that optimizes performance for terrestrial cloud transmission. The parity check matrix is constructed with particular structural properties that enhance reception robustness in co-channel interference environments, resolving the contradiction between reliability and adaptability.
2Adaptability or versatility
If frequency reuse is implemented to improve spectrum efficiency, then co-channel interference increases, making signal demodulation difficult without guaranteed synchronization
Solution Approach 1:
The patent converts the harmful effect of co-channel interference into a beneficial outcome by designing an LDPC code that specifically targets and mitigates interference patterns. The constructed parity check matrix creates codewords with properties that enable reliable demodulation even when multiple transmitters operate on the same frequency, thus converting the interference scenario into an opportunity for frequency reuse.
Solution Approach 2:
The patent applies beforehand cushioning by pre-designing the LDPC code structure to provide protection against co-channel interference before the interference actually affects reception. The specific parity check matrix construction creates inherent robustness that cushions the received signal against interference effects, enabling successful demodulation without requiring perfect synchronization.
3Adaptability or versatility
If an LDPC code with length 64800 and rate 7/15 is designed for general purposes, then versatility is improved, but encoding complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the 64800-length codeword into structured components with a specifically designed parity check matrix that has block structure. This segmentation allows the encoder to process the code in manageable sections rather than as a monolithic block, reducing encoding complexity while maintaining the versatility of the 64800-length code for general purposes.
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).