Polar Code Version Bit Mapping for Soft Combining in 5G
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Solution Overview
Problem
In 5G wireless communications, existing polar code technologies face challenges in explicitly indicating version information for transmitted payloads, leading to increased power consumption due to blind detection requirements, especially in scenarios like PBCH and HARQ transmissions.
Innovation Solution
A polar code encoding method that maps q bits to q positions of sub-channels to explicitly indicate the version of the encoded codeword, using a special frozen bit and performing polar encoding over an input vector with q bits and K-q information bits, allowing for soft combination without blind detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If blind detection is used to determine version information, then the receiver can identify transmitted payload versions, but power consumption increases significantly
Solution Approach 1:
The version information is pre-encoded into the codeword structure using q dedicated bits before transmission. This preliminary encoding allows the receiver to obtain version information directly from the received signal without performing multiple blind detection attempts, thereby significantly reducing power consumption while maintaining accurate version identification
Solution Approach 2:
The invention extracts q bits specifically dedicated to version information from the codeword structure. These q bits are separated from the information bits and frozen bits, allowing the receiver to directly read the version information without needing to perform blind detection across multiple hypotheses, thus reducing computational complexity and power consumption
2Use of energy by moving object
If version information is explicitly encoded, then power consumption is reduced by eliminating blind detection, but code structure complexity increases
Solution Approach 1:
The codeword is segmented into three distinct parts: q bits for version information, K-q information bits, and frozen bits. This segmentation allows the version information to be explicitly encoded in a dedicated space without interfering with the existing polar code structure, making the encoding process manageable and the structure organized rather than overly complex
Solution Approach 2:
The polar code structure is designed to serve multiple functions simultaneously: it encodes version information in q bits, transmits K-q information bits, and maintains frozen bits for channel polarization. This multi-functionality is achieved through a unified encoding framework that handles all these tasks within a single polar code structure, avoiding the need for separate complex systems
3Loss of information
If q bits are allocated for version information, then version indication capability is improved, but information bit capacity decreases
Solution Approach 1:
The code rate is adjusted as a parameter to compensate for the q bits allocated to version information. By changing the code rate, the system can maintain the desired information transmission capacity while incorporating the version information bits, effectively balancing the trade-off between version indication capability and information bit capacity
Data Source
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AI summary
A method to explicitly indicate the version information while still supporting soft combining is disclosed. A polar code encoder maps q bits to q positions of q sub-channels, q is a positive integer; wherein the q bits are used to indicate a version of encoded codeword; map 1 to a special frozen bit corresponding to the q bits; map K-q information bits to K-q positions for the K-q information bits, K is an integer, K>q; and perform polar encoding over an input vector u0 N-1, comprising the q bits, the special frozen bit and the K-q information bits, with the length of N, N is an integer, N>＝K. With this method, there is no need to make blind detection to achieve the version information of transmitted payload, which reduces power consumption for a receiver.