Polar Code Rate Matching With Unified Buffer-Based Length Adaptation
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Solution Overview
Problem
Polar codes in communication systems face limitations in code length flexibility and rate matching techniques, particularly in achieving optimal code lengths and adapting to varying channel conditions, which affects their performance in wireless communication networks.
Innovation Solution
The implementation of a method for polar code rate matching in communication devices that employs puncturing, shortening, or repetition techniques based on a unified scheme, using a rate matching controller to determine the appropriate polar code length and select the most reliable bit channels for information transmission, while adjusting the code length to match allocated transmission resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polar codes use fixed code lengths that are powers of two, then the encoding procedure is simple and well-defined, but the code length flexibility is limited and cannot adapt to varying transmission resource allocations
Solution Approach 1:
The patent applies dynamics by making the code length adaptable rather than fixed. The base polar code structure maintains fixed power-of-two lengths for simple encoding, while rate matching techniques dynamically adjust the effective code length to match transmission resource allocations. This allows the system to switch between fixed and variable length modes as needed.
Solution Approach 2:
The patent segments the code length adjustment into distinct rate matching operations (puncturing, shortening, repetition) that can be applied to the base polar code. Each technique divides the adjustment task into manageable operations that modify specific portions of the code while maintaining the overall structure.
2Adaptability or versatility
If rate matching techniques are implemented to achieve any code length, then code length flexibility improves, but the device complexity and implementation difficulty increase
Solution Approach 1:
The patent implements a unified rate matching framework that handles puncturing, shortening, and repetition through a common implementation structure. This universal approach allows the same base code structure to serve multiple rate matching functions, reducing overall implementation complexity despite the variety of techniques available.
Solution Approach 2:
The patent changes parameters such as code rate thresholds and rate matching technique selection based on channel conditions and transmission requirements. By dynamically adjusting these parameters, the system adapts code length to match resource allocations without requiring complete redesign of the encoding structure.
3Reliability
If puncturing or shortening is performed based on code rate comparison with threshold 1/2, then rate matching can be achieved, but the complexity increases and performance optimization is limited
Solution Approach 1:
The patent optimizes the code rate threshold parameter from the conventional 1/2 to a lower value better suited for control channel applications. This parameter change improves reliability by selecting more appropriate rate matching techniques for the specific use case, while the unified framework keeps the control complexity manageable.
Solution Approach 2:
The system uses feedback from channel conditions and transmission requirements to determine the optimal rate matching technique and threshold. This feedback mechanism allows the system to adapt to varying channel quality and resource allocations, improving reliability while maintaining reasonable control complexity through automated decision-making.
Data Source
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AI summary
Aspects of the disclosure provide polar code rate matching methods. A first method can include determining whether to puncture or shorten a mother polar code according to a mother code rate and/or a rate matched code rate, and selecting K positions in the sequence of N input bits for input of K information bits to a polar encoder according to an offline prepared index list ordered according to the reliabilities of respective synthesized channels. Frozen input bits caused by puncturing or shortening are skipped during the selection. A second method includes generating a mother polar code, rearranging code bits of the mother polar code to form a rearranged sequence that can be stored in a circular buffer, and performing, in a unified way, one of puncturing, shortening, or repetition on the rearranged sequence to obtain a rate matched code.