LDPC Bit Interleaving Scheme for QPSK Burst Error Resilience
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Solution Overview
Problem
Bit-Interleaved Coded Modulation (BICM) systems suffer from rapid performance degradation due to burst errors in digital broadcast channels, necessitating an optimized bit interleaver design for modulation order and error correction code parameters.
Innovation Solution
A bit interleaver is designed for an LDPC coder with a length of 64800 and code rate of 7/15, using a specific permutation order to interleave bit groups of 360 bits, optimized for QPSK modulation, effectively distributing burst errors and enhancing error correction performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a bit-by-bit interleaver is used in BICM systems, then the system can provide bandwidth-efficient transmission and flexibility in modulation order and code parameters, but the system suffers from rapid performance degradation due to burst errors in digital broadcast channels
Solution Approach 1:
The interleaver divides the LDPC codeword into multiple bit groups of equal size, where each bit group contains a specific number of bits. This segmentation allows the interleaver to process and distribute burst errors across different bit groups, preventing concentrated error patterns from overwhelming the error correction capability while maintaining the bandwidth efficiency of BICM systems.
2Reliability
If the bit interleaver is optimized for specific modulation order and code parameters, then error correction performance is improved, but the device complexity increases due to the need for optimized designs
Solution Approach 1:
The interleaver uses parameter-based design where the bit group size and permutation pattern are determined by mathematical parameters related to the LDPC code structure and modulation order. By changing these parameters according to different code rates and modulation schemes, the interleaver can be optimized for specific configurations without requiring completely different designs, thus improving error correction performance while controlling complexity through systematic parameter adjustment.
Data Source
AI summary
A bit interleaver, a bit-interleaved coded modulation (BICM) device and a bit interleaving method are disclosed herein. The bit interleaver includes a first memory, a processor, and a second memory. The first memory stores a low-density parity check (LDPC) codeword having a length of 64800 and a code rate of 7/15. The processor generates an interleaved codeword by interleaving the LDPC codeword on a bit group basis. The size of the bit group corresponds to a parallel factor of the LDPC codeword. The second memory provides the interleaved codeword to a modulator for quadrature phase shift keying (QPSK) modulation.