Recursive Polar Code Bit Allocation for Puncturing and Repetition
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Solution Overview
Problem
Conventional polar coding schemes face challenges in accommodating puncturing and bit repetition, leading to reduced throughput in wireless communications systems, as they do not adequately account for capacity differences in unpolarized bit-channels due to punctured bits, resulting in inefficient allocation of information bits.
Innovation Solution
The proposed solution involves a mutual-information based recursive polar code construction that adjusts initial target mutual information and recursively partitions bit-channels to account for punctured bits, ensuring information bits are allocated to the most reliable channels, using a method that identifies repeated and punctured bit locations and employs a mutual information transfer function based on binary erasure channel (BEC) and correction terms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polar coding schemes are used without adjustment for puncturing, then the encoding process is simple, but the throughput and reliability deteriorate due to inefficient bit allocation
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing mutual information values for different bit-channel partitions in lookup tables before actual encoding. This allows the encoder to quickly retrieve and use pre-computed mutual information values during encoding, avoiding complex real-time calculations while maintaining optimal bit allocation for punctured codes
Solution Approach 2:
The patent replaces complex real-time mutual information calculations with a lookup table-based system. Instead of performing mechanical computational operations during encoding, the system substitutes these with memory retrieval operations, significantly reducing computational complexity while preserving the ability to optimize bit allocation according to channel capacities
2Reliability
If conventional polar coding schemes are used without adjustment for puncturing, then the implementation is straightforward, but data transmission reliability deteriorates due to inefficient information bit allocation
Solution Approach 1:
The patent applies segmentation by dividing the code into different bit-channel partitions and separately determining mutual information for each partition. This allows the system to identify which partitions contain punctured bits and allocate information bits accordingly, ensuring that information bits are placed in reliable channels while frozen bits occupy unreliable or punctured positions
Solution Approach 2:
The patent changes the parameter of mutual information calculation by developing specific formulas that account for punctured bit positions. The mutual information values are adjusted based on the presence and position of punctured bits, allowing the bit allocation to adapt to the reduced channel capacity caused by puncturing
3Measurement precision
If mutual information calculations are performed for each punctured bit scenario, then bit allocation accuracy improves, but computational complexity increases
Solution Approach 1:
The patent pre-calculates mutual information values for various puncturing scenarios and stores them in lookup tables. This preliminary computation allows the system to achieve high measurement precision for channel capacities without performing complex calculations during actual encoding, as all necessary values are retrieved from pre-computed tables
Solution Approach 2:
The patent creates copies of mutual information calculation results for different puncturing patterns and stores them in lookup tables. Instead of recalculating mutual information for each encoding operation, the system copies and reuses pre-computed values, maintaining high measurement accuracy while minimizing computational complexity during runtime
Data Source
AI summary
Decoding and encoding methods, systems, and devices for wireless communication are described. One method may include receiving a codeword over a wireless channel, the codeword being encoded using a polar code, identifying a set of repeated bit locations in the received codeword, and identifying a set of bit locations of the polar code used for information bits for the encoding. The set of bit locations may be determined based at least in part on recursively partitioning bit-channels of the polar code for each stage of polarization and assigning portions of a number of the information bits to bit-channel partitions of each stage of polarization based on a mutual information transfer function of respective aggregate capacities of the bit-channel partitions. The method may also include decoding the received codeword according to the polar code to obtain an information bit vector at the set of bit locations, and other aspects and features.