Polar Code Rate Matching with Forced Frozen Bit Selection
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Solution Overview
Problem
Conventional Polar code rate matching methods have a large search space for determining shortened or punctured locations, leading to low search efficiency due to equivalent performance across multiple locations.
Innovation Solution
The method involves determining a first index set for forced frozen bits in the U domain, selecting sub-channels with the highest reliability for information bits, and using the remaining sub-channels for frozen bits, thereby reducing the search space in the X domain for rate matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shortened location or punctured location is searched for in the X domain, then rate matching can be performed, but search space is large and search efficiency is low
Solution Approach 1:
The patent applies preliminary action by determining the forced frozen bit locations in the U domain before performing rate matching in the X domain. This pre-determination of critical bit positions allows the system to focus the search for shortened or punctured locations only in regions that will actually affect performance, rather than searching the entire X domain. The method calculates which U domain bit positions correspond to forced frozen bits, then uses this information to identify candidate locations for rate matching operations, significantly reducing the search space while maintaining optimal performance.
2Reliability
If conventional rate matching methods are used with large search space, then all possible locations can be evaluated, but the quantity of operations is large and complexity increases
Solution Approach 1:
The patent extracts the essential information needed for rate matching by identifying and isolating the forced frozen bit locations in the U domain. Instead of evaluating all possible shortened or punctured locations in the X domain, the method extracts only the critical positions determined by the forced frozen bits. This extraction process creates a reduced set of candidate locations that must be evaluated, thereby maintaining performance optimization while dramatically reducing the number of operations and system complexity.
3Reliability
If multiple shortened locations or punctured locations are searched, then optimal performance can be found, but performance at multiple locations is basically equivalent making search unnecessary
Solution Approach 1:
The patent applies preliminary action by pre-calculating the forced frozen bit locations in the U domain before rate matching. This preliminary determination provides direct guidance on which locations in the X domain are worth evaluating, eliminating the need to search through multiple locations with equivalent performance. The method uses the pre-determined forced frozen bit positions to directly identify the optimal shortened or punctured locations, achieving both optimal performance and high search efficiency without exhaustive searching.
Data Source
AI summary
Example Polar code rate matching methods and apparatus are described. One example method includes determining indexes of Z polarized channels on which forced frozen bits are placed, where the Z polarized channels are a subset of N polarized channels corresponding to N to-be-encoded bits, where N=2n, Z<N, and n and Z are positive integers. A first codeword with a length of N is obtained by performing Polar coding on the N to-be-encoded bits. Rate matching is performed on the first codeword to obtain a second codeword with a length of M, where M<N and M is a positive integer. The second codeword with a length of M is sent.