Polar Code Sub-Channel Selection for Low-Complexity 5G Encoding
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Solution Overview
Problem
Polar codes for 5G wireless communications face challenges in efficiently selecting sub-channels for encoding and decoding, particularly in achieving optimal error correction performance due to the impracticality of long code lengths and the complexity of existing sub-channel reliability computation methods.
Innovation Solution
A method for determining and selecting sub-channels based on their reliabilities, using a processor-readable medium and apparatus with a sub-channel processing module to identify the most suitable sub-channels for encoding, allowing for efficient sub-channel selection and encoding without requiring complex online computations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long code lengths are used to achieve optimal error correction performance, then reliability is improved, but device complexity and computational burden increase making it impractical
Solution Approach 1:
The patent segments the code into multiple sub-channels with different reliability characteristics. By dividing the coding process into sub-channels, the system can achieve good error correction performance without requiring excessively long code lengths, thus reducing overall computational complexity while maintaining reliability.
Solution Approach 2:
The patent changes the parameter of code length by using shorter code lengths in conjunction with sub-channel selection. Instead of relying on very long codes to achieve reliability, the system adjusts the code length parameter downward and compensates through intelligent sub-channel selection, thereby reducing computational burden while maintaining error correction performance.
2Reliability
If sub-channel reliability computation is performed online to achieve optimal sub-channel selection, then reliability is improved, but device complexity and processing time increase
Solution Approach 1:
The patent applies preliminary action by pre-computing sub-channel reliability values before the actual encoding process. The base station determines sub-channel reliabilities in advance based on channel conditions, allowing optimal sub-channel selection without performing complex computations during online operation, thus reducing real-time processing complexity while maintaining selection accuracy.
Solution Approach 2:
The patent uses copying by having the base station and user equipment both store and use the same sub-channel reliability information. The base station computes reliabilities and communicates this information to the user equipment, allowing both ends to make consistent sub-channel selection decisions without duplicating complex computation at both ends, reducing overall system complexity.
3Productivity
If more sub-channels are selected to carry encoded bits, then productivity is improved, but reliability decreases due to selection of lower quality sub-channels
Solution Approach 1:
The patent applies local quality by assigning different quality levels to different sub-channels based on their reliability characteristics. Higher reliability sub-channels are selected to carry encoded bits, while lower reliability sub-channels are used for other purposes or left unused. This ensures that as more sub-channels are utilized for productivity, the system maintains reliability by preferentially using high-quality sub-channels.
Data Source
AI summary
Coding sub-channel selection involves, in an embodiment, determining, from sub-channels that are defined by a code and that have associated reliabilities for input bits at input bit positions, a first number of the sub-channels to carry bits that are to be encoded. A second number of the sub-channels, greater than the first number, are selected. The second number of sub-channels are selected to provide exactly the first number sub-channels to be available to carry the bits that are to be encoded.