Polar Code Information Sequences for Finite-Length Decoding
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Solution Overview
Problem
Polar codes, despite being provable to achieve symmetric capacity, have finite-length performance issues under Successive Cancellation decoding that makes them less competitive with LDPC and Turbo codes, and existing information sequences impose artificial relationships among bit channels, affecting decoding efficiency.
Innovation Solution
Optimized information sequences for specific code lengths, such as those provided for N=64 and N=128, are used to improve polar encoding performance by mapping information bits to optimal bit locations, taking into account the performance of SC and SCL decoders at different Block Error Rates, thereby enhancing decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Polarization Weight sequences are used for polar encoding, then the coding scheme achieves symmetric capacity under low-complexity Successive Cancellation decoding, but the finite-length performance is not competitive compared to LDPC and Turbo codes
Solution Approach 1:
The patent applies parameter changes by optimizing the information sequence specifically for code length N=64, rather than using general Polarization Weight sequences. This involves determining bit channel reliabilities through actual decoding operations and arranging information bits according to these specific reliability values, thereby improving finite-length performance while maintaining the Successive Cancellation decoding structure.
2Ease of operation
If information bits are mapped to bit channel locations based on general Polarization Weight sequences, then the encoding process is simplified, but artificial relationships among bit channels are imposed, affecting decoding efficiency
Solution Approach 1:
The patent applies local quality by determining bit channel reliabilities specifically for each code length (e.g., N=64) through actual decoding operations. Instead of using a universal mapping rule, the information sequence is locally optimized for each specific code length, allowing the system to adapt to the specific characteristics of different code lengths and improve decoding efficiency without complicating the encoding process.
3Adaptability or versatility
If the same information sequence is used for all code lengths, then the system design is simplified, but the performance does not account for specific code length characteristics
Solution Approach 1:
The patent applies segmentation by dividing the information sequence design into separate optimized sequences for different code lengths (e.g., S64 for N=64, S128 for N=128). Each sequence is independently determined based on the specific characteristics of its code length, allowing the system to achieve better performance for each specific length while maintaining a systematic approach through the use of Successive Cancellation and SCL decoding methods.
Data Source
AI summary
Systems and methods are disclosed for performing polar encoding of a number of information bits for transmission in a wireless communication system in a manner that is optimized for a specific code length. In some embodiments, a method of operation of a transmit node in a wireless communication system comprises performing polar encoding of a set of K information bits to thereby generate a set of polar-encoded information bits where the K information bits are mapped to the first K information bit locations specified in an information sequence SN which is a ranked sequence of N information bit locations among a plurality of input bits for the polar encoding where N is equivalent to a code length, a size of the information sequence SN is greater than or equal to K, and the information sequence SN is optimized for a specific value of the code length N.