Polar Code Rate Matching with Bit-Channel Preallocation
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Solution Overview
Problem
Polar code processing is computationally intensive, and existing rate matching techniques may compromise the gains associated with using polar codes, leading to reduced throughput in wireless communications systems.
Innovation Solution
Implement rate matching schemes such as puncturing, shortening, or repetition, and use lookup tables or interpolation functions to determine bit channel locations based on transmission capacity factors, allowing for efficient encoding and decoding of polar codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polar code processing is used to achieve error correction capability approaching theoretical channel capacity, then reliability is improved, but computational complexity increases
Solution Approach 1:
The patent segments the polar code processing into distinct stages: channel polarization transformation, bit channel capacity calculation, information bit allocation to specific bit channels, and rate matching. This segmentation allows each stage to be optimized independently, reducing overall computational complexity while maintaining the theoretical error correction capabilities of polar codes
Solution Approach 2:
The patent performs preliminary calculations of bit channel capacities and determines optimal information bit allocations before actual encoding. By pre-calculating which bit channels should carry information bits based on their capacities, the system avoids complex real-time decisions during encoding, thereby reducing computational complexity while preserving reliability
2Adaptability or versatility
If rate matching is applied to achieve given code rate or codeword size, then adaptability is improved, but throughput is reduced
Solution Approach 1:
The patent determines the optimal set of bit locations for information bits before rate matching is applied. By pre-calculating which bit channels should carry information based on the target code rate and channel conditions, the system minimizes the impact of rate matching on throughput while achieving the required adaptability to different code rates
Solution Approach 2:
The patent changes the allocation of information bits to different bit channels based on calculated capacities and rate matching requirements. By dynamically adjusting which bit channels carry information bits according to channel conditions and target code rates, the system achieves adaptability without significant throughput loss
3Ease of operation
If lookup tables are used to map transmission capacity factors to codeword length or transmitted bits, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent uses lookup tables that can be pre-computed and stored in memory, replacing complex real-time calculations with simple table lookups. The lookup tables contain pre-calculated mappings between transmission capacity factors and optimal bit channel allocations, making the encoding process much simpler to operate while the memory overhead is acceptable for the performance gain
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described for polar coding with rate matching. A transmitter may construct input channels into a polar encoder to provide an information bit vector that does not include punctured or shortened bits. One or more transmission capacity factors may be used in identifying the information bit vector, which may be mapped to one or more of a codeword length of the polar code or a number of transmitted bits in each codeword. A number of different rate matching schemes may be available for transmissions, and may be selected based on one or more polar coding parameters. In some cases, mapping techniques may be used in two or more different rate matching schemes.