Polar Code Puncturing Selection for Variable Block Lengths
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Solution Overview
Problem
Existing wireless communication networks face challenges in achieving reliable and efficient information transfer due to limitations in block codes, particularly for future networks beyond LTE, where polar codes offer potential but require enhancements for variable block lengths.
Innovation Solution
The method involves generating polar codewords with variable block lengths using puncturing, where the puncturing scheme is selected based on log likelihood ratios (LLRs) to determine whether punctured bits are considered unknown or known, optimizing performance across different coding rates and signal-to-noise ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polar codes are used for future wireless networks beyond LTE, then improved performance and reliability are achieved, but limitations in supporting variable block lengths hinder deployment
Solution Approach 1:
The patent applies dynamics by making the puncturing pattern configurable and adaptable to different code lengths. The system dynamically selects between different puncturing schemes (first and second puncturing patterns) based on the desired code length and channel conditions, enabling polar codes to flexibly support variable block lengths while maintaining optimal performance across different transmission scenarios
Solution Approach 2:
The patent changes the parameter of puncturing pattern selection based on code length requirements and channel conditions. By adjusting which bits are punctured according to different patterns, the system adapts the polar code structure to support various block lengths while preserving the reliability benefits of polar coding
2Adaptability or versatility
If puncturing is applied to achieve variable codeword lengths, then flexibility in code length is improved, but performance degradation may occur due to suboptimal puncturing schemes
Solution Approach 1:
The patent implements dynamics by introducing adaptive selection between multiple puncturing schemes. The receiving device determines which puncturing pattern was used based on feedback or predefined agreements, and the transmitting and receiving devices dynamically adjust their puncturing/depuncturing operations based on channel conditions and code length requirements, thereby maintaining optimal decoding performance across variable code lengths
Solution Approach 2:
The patent employs feedback mechanisms where the receiving device sends feedback information to the transmitting device about channel conditions and decoding status. This feedback enables the transmitting device to adjust the puncturing pattern selection, ensuring that the most appropriate scheme is used for current channel conditions, thus preventing performance degradation
3Device complexity
If fixed puncturing schemes are used, then implementation complexity is reduced, but performance is suboptimal across different coding rates and SNRs
Solution Approach 1:
The patent achieves universality by designing a puncturing system that can operate with multiple different puncturing patterns within a single framework. The same basic puncturing mechanism can adapt to different code lengths, coding rates, and channel conditions by selecting from the first and second puncturing patterns, eliminating the need for separate fixed schemes for each scenario while maintaining implementation simplicity
Data Source
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AI summary
Polar codes may be generated with a variable block length utilizing puncturing. Some puncturing schemes consider punctured bits as unknown bits, and set the log likelihood ratio (LLR) for those bits to zero; while other puncturing schemes consider punctured bits as known bits, and set the LLR for those bits to infinity. Each of these puncturing schemes has been observed to provide benefits over the other under different circumstances, especially corresponding to different coding rates or different signal to noise ratio (SNR). According to aspects of the present disclosure, both puncturing schemes are compared, and the puncturing scheme resulting in the better performance is utilized for transmission.