LDPC Bit Interleaver Permutation for QPSK Burst Error Spreading

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

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 optimized for an LDPC coder with a length of 64800 and code rate of 3/15, using a specific permutation order for bit group-based interleaving, is designed to effectively distribute burst errors, compatible with QPSK modulation for next-generation broadcasting systems like ATSC 3.0.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional bit interleaver is used in BICM systems, then the system structure remains simple, but burst errors in digital broadcast channels cause rapid performance degradation

Engineering Contradiction:

Improvesystem performanceVSAvoidburst errors

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The bit interleaver divides the codeword into multiple bit groups and applies different permutation patterns to different segments. This segmentation allows burst errors to be distributed across multiple code blocks rather than concentrated in one location, thereby improving error distribution and system reliability under burst error conditions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The interleaver uses dynamic permutation patterns that adapt to different modulation orders and code rates. By dynamically adjusting the interleaving strategy based on channel conditions and system parameters, the system maintains optimal performance while defending against burst errors without requiring a completely complex structure

Inventive Principle:

Principle #15Dynamics

2Reliability

If the bit interleaver is optimized for specific modulation order and code rate parameters, then performance is improved, but the device complexity increases

Engineering Contradiction:

ImproveperformanceVSAvoidinterleaver design complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interleaver design changes key parameters such as bit group size, permutation pattern length, and interleaving depth to match specific modulation orders and code rates. By adjusting these parameters rather than redesigning the entire interleaver structure, the system achieves optimized performance for specific configurations while controlling design complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The interleaver is designed with a universal structure that can handle multiple modulation orders and code rates by configuring different permutation patterns. This multi-functional design allows a single interleaver architecture to serve various BICM configurations, improving performance across different scenarios without proportionally increasing device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10333556B2Bit interleaver for low-density parity check codeword having length of 64800 and code rate of 3/15 and quadrature phase shift keying, and bit interleaving method using same

Publication Date: 2019.06.25 ELECTRONICS & TELECOMM RES INST

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 3/15. 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.