Nested Polar Code Construction for Flexible Error Correction
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Solution Overview
Problem
Current wireless communication networks face challenges in achieving reliable and efficient information transfer due to noise in communication channels, particularly for future networks beyond LTE, where existing block codes like turbo codes and LDPC codes have limitations in error correction performance.
Innovation Solution
The use of polar codes generated using a single master sequence constructed via density evolution with a nested structure to identify frozen and information bit locations, enabling efficient error correction across varying channel conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing block codes (turbo codes, LDPC codes) are used for error correction in wireless communication channels, then implementation is straightforward with established standards, but error correction performance is insufficient for future networks beyond LTE
Solution Approach 1:
The patent applies parameter changes by modifying the code construction parameters of polar codes. Specifically, it uses density evolution to calculate bit reliability parameters and determines optimal code rates and block lengths. The nested structure allows dynamic adjustment of code parameters (code rate, block length) to adapt to different channel conditions and future network requirements, thereby improving error correction performance while maintaining versatility.
2Reliability
If polar codes are constructed with optimized error correction performance for specific code rates and block lengths, then error correction capability improves, but the system becomes less flexible for varying channel conditions
Solution Approach 1:
The patent implements universality through the nested structure of polar codes. The master sequence generated by density evolution serves as a universal foundation from which multiple code rates and block lengths can be derived. This allows a single master sequence to support multiple code configurations (e.g., different code rates R and block lengths N), enabling the system to adapt to varying channel conditions while maintaining optimized error correction performance across different scenarios.
Solution Approach 2:
The patent applies dynamics by enabling dynamic selection of code parameters based on channel conditions. The nested structure allows the system to dynamically adjust code rate and block length according to the signal-to-noise ratio and channel quality. This dynamic adaptation ensures optimal error correction capability is maintained across varying channel conditions without requiring separate fixed-parameter code constructions.
3Reliability
If multiple master sequences are constructed for different code rates and block lengths, then optimal performance is achieved for each specific configuration, but system complexity and storage requirements increase
Solution Approach 1:
The patent applies the nested doll principle by creating a hierarchical nested structure where a single master sequence contains within it the information needed to generate multiple code configurations. The master sequence is nested over a code rate vector, allowing different code rates and block lengths to be derived from the same foundational sequence. This eliminates the need to store and process multiple separate master sequences, thereby reducing system complexity and storage requirements while maintaining optimal performance for each configuration.
4Reliability
If traditional code construction methods are used, then implementation is simple with well-established algorithms, but performance is limited compared to density evolution-based construction
Solution Approach 1:
The patent applies preliminary action by pre-calculating the master sequence using density evolution before actual code transmission. The density evolution process computes bit reliability parameters and determines the optimal master sequence in advance, based on expected channel conditions and code rate requirements. This preliminary construction phase, while computationally intensive, is performed offline or during system initialization, allowing the actual encoding and decoding operations to use the pre-optimized master sequence, thereby achieving high performance without excessive real-time complexity.
Data Source
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.