LDPC Codeword Interleaving for High-Order Modulation Mapping
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Solution Overview
Problem
In communication and broadcasting systems, high digital communication systems face challenges due to noise, fading, and inter-symbol interference, which affect data throughput and reliability, particularly in next-generation mobile communication and digital broadcasting. The performance of Low Density Parity Check (LDPC) codes is dependent on how codeword bits are mapped onto high-order modulation bits, requiring an effective method for bit mapping to achieve good performance.
Innovation Solution
A transmitting apparatus and signal processing method that includes an encoder for generating LDPC codewords, an interleaver for rearranging bit groups based on modulation order, and a modulator to generate modulation symbols. The interleaver divides the LDPC codeword into bit groups, rearranges their order, and maps them onto modulation symbols, using techniques like group and block interleaving to optimize bit placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC codeword bits are mapped onto high-order modulation bits using conventional methods, then the system complexity is reduced, but the communication reliability and throughput deteriorate due to noise and interference
Solution Approach 1:
The LDPC codeword is divided into multiple bit groups, and each bit group is further segmented into sub-bit groups. This segmentation allows for systematic interleaving and mapping operations that improve reliability while maintaining manageable complexity through structured processing.
Solution Approach 2:
The patent applies preliminary interleaving operations on bit groups and sub-bit groups before the actual modulation mapping. This preliminary rearrangement of bits optimizes the distribution of codeword bits across modulation symbols, enhancing robustness against noise and interference before the signal is transmitted.
2Productivity
If conventional bit mapping is used for high-order modulation, then the device complexity is low, but the data throughput and reliability deteriorate due to channel noises and fading
Solution Approach 1:
The interleaving process is segmented into multiple stages: first dividing the LDPC codeword into bit groups, then further dividing into sub-bit groups. This multi-level segmentation enables efficient throughput optimization while keeping each individual interleaving operation manageable in complexity.
Solution Approach 2:
The patent introduces a two-dimensional interleaving structure by first interleaving within bit groups and then interleaving across sub-bit groups. This dimensional approach to interleaving maximizes data throughput by optimizing bit distribution across multiple dimensions of the modulation signal.
3Reliability
If simple bit mapping is applied to LDPC codewords, then the system is easier to implement, but the performance deteriorates due to inter-symbol interference and fading
Solution Approach 1:
The patent performs preliminary interleaving operations on bit groups and sub-bit groups before modulation mapping. This preliminary action optimizes the bit distribution to combat inter-symbol interference and fading, achieving improved error correction performance while maintaining implementation feasibility through systematic processing.
Solution Approach 2:
The patent changes the mapping parameters by introducing group-based interleaving with specific group sizes and sub-group divisions. These parameter changes optimize the mapping to achieve better error correction performance while keeping the implementation complexity manageable through standardized parameter sets.
Data Source
AI summary
A transmitting apparatus and a receiving apparatus are provided. The transmitting apparatus includes an encoder configured to generate a low density parity check (LDPC) codeword by performing LDPC encoding, an interleaver configured to interleave the LDPC codeword, and a modulator configured to modulate the interleaved LDPC codeword according to a modulation method to generate a modulation symbol. The interleaver performs interleaving by dividing the LDPC codeword into a plurality of groups, rearranging an order of the plurality of groups in group units, and dividing the plurality of rearranged groups based on a modulation order according to the modulation method.