Symbol Mapping for Repetition Channel Coding Reliability
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Solution Overview
Problem
Current wireless communication systems, such as IEEE 802.16, face suboptimal decoding throughput due to uneven reliability of codeword bits when using repetition coding, particularly on control channels, as they lack a specific mapping order for codeword bits converted to channel symbols, leading to poor decoding performance.
Innovation Solution
A symbol mapping method that performs repetition coding on codeword bits and maps the repeated codeword symbols with subcarriers in localized or distributed resource blocks, maximizing the distance between subcarriers to ensure maximum reliability and improve decoding throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If repetition coding is performed on codeword bits without specific mapping order, then system coverage and throughput are improved, but decoding performance deteriorates due to uneven reliability of codeword bits
Solution Approach 1:
The patent applies local quality by differentiating the treatment of different codeword bits based on their reliability characteristics. Specifically, it identifies bits with low reliability (such as those at positions susceptible to fading) and applies special mapping or repetition strategies to these specific bits, rather than treating all bits uniformly. This allows the system to maintain high decoding throughput while ensuring that critical bits achieve the necessary reliability threshold.
Solution Approach 2:
The patent implements preliminary action by performing reliability assessment and selective mapping before the actual transmission process. The system pre-identifies which codeword bits will have low reliability based on channel characteristics and modulation scheme, then pre-arranges their mapping to subcarriers or applies repetition coding in advance. This preliminary preparation ensures that when transmission occurs, the most vulnerable bits are already protected through optimal positioning or redundancy, thereby improving decoding performance without sacrificing throughput.
2Device complexity
If codeword bits are mapped to subcarriers without considering channel variation, then mapping complexity is reduced, but decoding performance worsens due to deep fading affecting specific bits
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the mapping parameters (such as subcarrier index or resource block allocation) based on channel conditions. Instead of using a fixed mapping scheme, the system modifies mapping parameters according to identified low-reliability bits and current channel state. This allows the mapping process to adapt to channel variations without requiring complex real-time optimization, achieving improved reliability while maintaining manageable complexity through rule-based parameter adjustment.
Data Source
AI summary
A symbol mapping method for repetition coding is disclosed. The symbol mapping method comprises performing repetition coding on codeword to output repeated codeword symbols, and mapping the repeated codeword symbols with subcarriers located in different localized resource blocks. According to the embodiments of the present invention, it is possible to obtain maximum reliability in a receiving side by mapping codeword bits with subcarriers to reduce the number of bits having low reliability when a transmitting side uses repetition coding. Also, it is possible to improve decoding throughput and obtain channel diversity.