Nested Polar Code Construction Using a Density-Evolution Master Sequence
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently generating polar codewords for reliable information transfer, particularly in noisy channels, as existing methods like turbo codes and LDPC codes have limitations in error correction and complexity for future wireless networks beyond LTE.
Innovation Solution
The generation of polar codewords using a single master sequence constructed via density evolution with a nested structure, which identifies frozen and information bit locations, allowing for flexible codeword lengths and code rates, enhancing reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional methods (turbo codes, LDPC codes) are used for error correction in wireless communication, then error correction capability is provided, but complexity increases and performance is limited for future networks beyond LTE
Solution Approach 1:
The patent changes the fundamental parameters of polar code construction by using density evolution to calculate bit error probabilities and determine optimal frozen bit positions. This transforms the code construction process from fixed patterns to dynamically optimized parameters, achieving better error correction performance with controlled complexity
Solution Approach 2:
The patent segments the polar code construction into distinct phases: density evolution calculation, frozen bit position identification, and codeword generation. This segmentation allows each phase to be optimized independently, managing overall system complexity while improving reliability
2Reliability
If polar codes are used for reliable information transfer, then performance is improved, but generation complexity increases for identifying frozen and information bit locations
Solution Approach 1:
The patent performs preliminary density evolution calculations to pre-determine the optimal frozen bit positions before actual code generation. This preliminary action creates a lookup table or predefined sequence that simplifies the bit location identification process during runtime, reducing operational complexity while maintaining high reliability
Solution Approach 2:
The patent introduces density evolution as an intermediary process that bridges the gap between theoretical polar code construction and practical implementation. This intermediary calculates bit error probabilities and translates them into concrete frozen bit position selections, simplifying the overall system architecture
3Ease of manufacture
If fixed codeword lengths are used for polar codes, then construction is simplified, but adaptability to different code rates and lengths is reduced
Solution Approach 1:
The patent creates a universal frozen bit position sequence that can be applied across multiple codeword lengths and code rates. The density evolution-based construction produces a master sequence from which subsets can be derived for different configurations, enabling one system to serve multiple functions and adapt to various requirements without redesign
Data Source
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AI summary
Aspects of the disclosure relate to wireless communication devices configured to generate polar codewords utilizing a single master sequence constructed using density evolution with a nested structure for identifying the frozen bit locations and information bit locations. This single master sequence may be used for any codeword length N up to a maximum codeword length Nmax, and may further be utilized for any code rate R. For example, from the master sequence of length Nmax, a bit location sequence S with codeword length N (where N ＜ Nmax) may be obtained by selecting the bit locations (indexes) in the master sequence corresponding to each bit location in S in the order provided in the master sequence.