Polar Code Rate Matching via Forced Frozen Bit Indexing
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Solution Overview
Problem
Existing Polar code rate matching methods face inefficiencies due to a large search space for determining shortened or punctured locations in the codeword field, leading to low search efficiency.
Innovation Solution
The proposed method reduces the search space by determining a set of indexes for sub-channels with forced frozen bits in the U domain, which then dictates the shortened or punctured locations in the X domain, thereby streamlining the rate matching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shortened or punctured locations are determined by searching in the X domain, then rate matching can be performed, but the search space becomes large and search efficiency decreases
Solution Approach 1:
Instead of determining shortened or punctured locations by searching in the X domain (codeword space), the patent inverts the approach by first determining the location of forced frozen bits in the U domain (information bit space), and then deriving the shortened or punctured locations in the X domain based on this determination. This inversion significantly reduces the search space and improves search efficiency while maintaining rate matching performance.
2Reliability
If a large quantity of shortened or punctured locations are searched in the X domain, then better rate matching performance may be obtained, but the complexity of the process increases
Solution Approach 1:
The patent applies preliminary action by first determining the location of forced frozen bits in the U domain before proceeding to determine shortened or punctured locations in the X domain. This preliminary determination provides a constrained starting point that reduces the subsequent search space and simplifies the overall process complexity while still achieving optimal rate matching performance.
Data Source
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AI summary
This application provides a Polar code rate matching method and apparatus, so that a search space of a codeword field can be reduced when a Polar code rate matching solution is selected. The method includes: determining a first index set corresponding to N to-be-encoded bits, where the first index set includes indexes of Z polarized channels on which forced frozen bits are placed, the Z polarized channels are a subset of N polarized channels corresponding to the N to-be-encoded bits, N=2n, Z<N, and n and Z are positive integers; obtaining a first codeword with a length of N, where the first codeword is obtained by performing Polar coding on the N to-be-encoded bits; performing rate matching on the first codeword based on the first index set, to obtain a second codeword with a length of M, where M<N and M is a positive integer; and sending the second codeword with a length of M.