Polar Code Rate Matching With Adjusted M Bit Allocation
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Solution Overview
Problem
Traditional rate matching schemes for polar codes in wireless communication systems, such as those used in new radio (NR) technology, can lead to performance losses due to improper bit allocation during block puncturing and shortening, especially when the number of encoded bits (M) is slightly larger than half of the code size (N/2), causing inefficiencies in successive cancellation decoding.
Innovation Solution
The method involves iteratively determining a new parameter, Madj, based on parameters α and β, to adjust the information bit allocation between the upper and lower parts of the polar code, thereby optimizing the number of encoded bits (M) for improved decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rate matching schemes are used for polar codes, then the encoding process is simple, but decoding performance deteriorates due to improper bit allocation during block puncturing and shortening
Solution Approach 1:
The patent changes the parameter M (number of encoded bits) used in rate matching calculations to Madj (adjusted number of encoded bits). This parameter adjustment resolves the bit allocation problem during block puncturing and shortening, improving successive cancellation decoding performance while maintaining manageable complexity through a controlled iterative process with parameters alpha and beta.
Solution Approach 2:
The patent introduces a dynamic adjustment mechanism where Madj is determined iteratively based on parameters alpha and beta. This dynamic approach adapts the rate matching process to different coding scenarios, optimizing bit allocation for both block puncturing and shortening operations rather than using a static traditional scheme.
2Productivity
If the number of encoded bits M is slightly larger than N/2, then the code rate is improved, but performance spikes occur due to heavily-punctured subblocks
Solution Approach 1:
The patent applies preliminary anti-action by adjusting M to Madj before the rate matching process. This pre-adjustment prevents the formation of heavily-punctured subblocks that would cause performance spikes, allowing the system to achieve higher code rates (M slightly larger than N/2) without the associated performance degradation.
3Measurement precision
If iterative determination of Madj is performed, then bit allocation accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent implements a feedback-controlled iterative process where Madj is determined through successive approximations using parameters alpha and beta. The iteration incorporates feedback from previous calculations to refine the bit allocation accuracy while converging to a stable solution, balancing precision with computational feasibility.
Data Source
AI summary
Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to methods and apparatus for adjusting a number of encoded bits, M, in block puncturing and/or shortening calculations to improve encoding performance. An exemplary method that may be performed by a wireless device generally includes iteratively determining a parameter, Madj, for construction of a polar code of size N for use in encoding K information bits, based on: at least two parameters, α and β, related to how many iterations to use in determining Madj, and a number of encoded bits, M; performing information adjustment allocation of the K information bits to an upper part and a lower part of the polar code based on Madj; and transmitting the upper part and the lower part of the polar code via a wireless medium.