Convolutional Turbo Coding With Reliability-Based Bit Mapping
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Solution Overview
Problem
In Convolutional Turbo Coding (CTC) methods for wireless mobile communication systems, bit reliability is not considered during high order modulation, leading to unequal error protection and reduced reliability of bits in high order modulation schemes.
Innovation Solution
The proposed method involves encoding information bits A and B using a constituent encoder to generate parity sequences, interleaving these sequences, and alternately mapping bits from bit groups to constellation points with high and low reliability to improve coding reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high order modulation is used to increase data transmission rate, then productivity is improved, but reliability deteriorates due to unequal error protection of bits
Solution Approach 1:
The patent applies local quality by differentiating the treatment of bits based on their reliability characteristics. Bits are divided into groups according to their reliability (e.g., most reliable, reliable, least reliable), and different mapping strategies are applied to different groups. This allows the system to optimize for both high transmission rate and improved reliability by treating different bits differently rather than uniformly.
Solution Approach 2:
The patent changes the mapping parameter by introducing reliability-based mapping where the mapping relationship between bits and constellation points is adjusted according to bit reliability. Instead of fixed mapping, the system dynamically assigns bits to constellation points based on their reliability characteristics, thereby improving overall system reliability while maintaining high data transmission rates.
2Reliability
If conventional CTC encoding is used, then device complexity is maintained at acceptable levels, but reliability is insufficient due to lack of bit reliability consideration
Solution Approach 1:
The patent segments the bit stream into multiple groups based on reliability characteristics before encoding. By dividing bits into distinct reliability groups (e.g., first group with highest reliability, second group with medium reliability, third group with lowest reliability), the system can apply different encoding and mapping strategies to each segment, improving overall reliability without substantially increasing complexity.
Solution Approach 2:
The patent performs preliminary classification of bits into reliability groups before the actual encoding process. This preliminary action of grouping bits according to their reliability allows subsequent encoding stages to be optimized for each group, improving coding reliability while keeping the additional complexity manageable through structured pre-processing.
Data Source
AI summary
A method and apparatus for Convolutional Turbo Coding (CTC), and an apparatus for a turbo encoder are provided. The method for CTC includes the steps of encoding information bits A and B using a constituent encoder, and outputting parity sequences Y1 and W1, interleaving the information bits A and B using a CTC interleaver to obtain information bits C and D, and encoding the interleaved information bits C and D using the constituent encoder to obtain parity sequences Y2 and W2, interleaving the information bits A and B, the parity sequences Y1 and W1 and the parity sequences Y2 and W2, respectively, wherein the bits in at least one of a bit group constituted of the information bits A and B, a bit group constituted of the sequences Y1 and W1, and a bit group constituted of the sequences Y2 and W2 are alternately mapped to bits of constellation points with high reliability and low reliability and puncturing the interleaving result to obtain the encoded bit sequences.