LDPC Bit Interleaver Layout for 1024-Symbol Burst Error Spreading
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Solution Overview
Problem
Bit-Interleaved Coded Modulation (BICM) systems face rapid performance degradation unless burst errors in digital broadcast channels are effectively distributed, requiring optimization of bit interleavers for specific modulation orders and error correction code lengths.
Innovation Solution
A bit interleaver optimized for an LDPC coder with a length of 64800 and code rate of 2/15, using 1024-symbol mapping, is designed to effectively distribute burst errors by interleaving the LDPC codeword on a bit group basis according to a specific permutation order, suitable for next-generation broadcasting systems like ATSC 3.0.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bit interleaver is optimized for specific modulation orders and code rates, then error correction performance is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by developing specific interleaving sequences tailored to different modulation orders (e.g., 1024-QAM) and code rates (e.g., 2/15). The interleaver uses optimized permutation sequences that adapt to the specific parameters of the communication system, thereby improving error correction performance for each configuration without requiring a completely different interleaver structure.
Solution Approach 2:
The interleaver divides the codeword into multiple bit groups and applies different interleaving sequences to different segments. This segmentation allows the system to handle burst errors more effectively by distributing them across different symbol groups, while maintaining a manageable interleaver structure that doesn't require complete redesign for different system parameters.
2Reliability
If burst errors are distributed through bit interleaving, then reliability is improved, but the processing time increases
Solution Approach 1:
The interleaving sequences are pre-calculated and stored in lookup tables. During transmission, the interleaver simply applies the pre-determined permutation to the bit groups, which significantly reduces processing time compared to calculating interleaving sequences in real-time. This preliminary preparation allows fast application of complex interleaving patterns.
Solution Approach 2:
The interleaver uses periodic interleaving patterns where bits are distributed at regular intervals across symbol groups. This periodic structure simplifies the interleaving operation while effectively spreading burst errors throughout the transmitted signal, reducing both processing complexity and time requirements.
Data Source
AI summary
A bit-interleaved coded modulation (BICM) reception device and a BICM reception method are disclosed herein. The BICM reception device includes a demodulator, a bit deinterleaver, and a decoder. The demodulator performs demodulation corresponding to 1024-symbol mapping. The bit deinterleaver performs group-unit deinterleaving on interleaved values. The interleaved values are generated after the demodulation. The decoder restores information bits by LDPC-decoding deinterleaved values generated based on the group-unit deinterleaving. The deinterleaved values corresponds to a LDPC codeword having a length of 64800 and a code rate of 2/15.