64800-Bit LDPC Encoding for Frequency Reuse Under Co-Channel Interference
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Solution Overview
Problem
Current terrestrial TV broadcasting systems face significant co-channel interference issues, leading to white spaces where frequency reuse is not possible, resulting in deteriorated spectrum efficiency, especially in areas where timing and frequency synchronization between signals are not guaranteed.
Innovation Solution
A new Low Density Parity Check (LDPC) code with a length of 64800 and a code rate of 4/15 is developed, utilizing an LDPC encoder and decoder that efficiently perform LDPC encoding and decoding using a specific sequence corresponding to a parity check matrix, allowing for robust signal reception and demodulation in overlapping areas with co-channel interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If terrestrial TV broadcasting uses conventional frequency allocation, then co-channel interference is reduced, but spectrum efficiency deteriorates due to white spaces where frequency cannot be reused
Solution Approach 1:
The patent applies parameter changes by optimizing the LDPC code rate (4/15) and code length (64800) to achieve superior error correction performance. This enables frequency reuse in overlapping areas while maintaining reception robustness, thereby eliminating white spaces and improving spectrum efficiency without sacrificing reliability
Solution Approach 2:
The patent converts the harmful effect of co-channel interference into a benefit by enabling frequency reuse. Through optimized LDPC encoding, the system can tolerate and correct errors from overlapping signals, transforming the previously harmful interference into an opportunity for improved spectrum utilization and elimination of white spaces
2Reliability
If LDPC code length is increased to improve error correction, then reception robustness improves, but encoding complexity increases
Solution Approach 1:
The patent segments the 64800-bit codeword into manageable blocks and uses a structured parity check matrix with specific patterns. This segmentation approach allows the encoder to process long codewords efficiently by breaking them into smaller operational units, reducing encoding complexity while maintaining the error correction capability provided by the long code length
Solution Approach 2:
The patent optimizes the balance between code length (64800) and code rate (4/15) to achieve the desired error correction performance. By carefully selecting these parameters and using an optimized encoding algorithm, the system achieves high reliability without excessive encoding complexity
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 4/15. 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).