Polar Code Known-Bit Mapping for Early Termination and BLER

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Solution Overview

Problem

In 5G NR communication systems, the placement of known or partially known bits in polar codes for the new radio physical broadcast channel (NR-PBCH) does not effectively optimize both early decoding termination and block error rate, as existing solutions fail to balance competing performance criteria such as minimizing block error rate and decoding latency.

Innovation Solution

A method is introduced to identify and place subsets of known payload bits in polar encoding to optimize early decoding termination and error performance, using a known-bit interleaver or mapper to position bits in the earliest and least reliable decoding positions, respectively, within the polar encoder, thereby enhancing the performance criteria.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If known bits are placed in the earliest decoding positions to improve early termination gain, then decoding latency is reduced, but block error rate performance deteriorates

Engineering Contradiction:

Improvedecoding latencyVSAvoidblock error rate

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The known bits are segmented into two distinct subsets: a first subset placed in earliest decoding positions to improve early termination, and a second subset placed in least reliable positions to improve block error rate. This segmentation allows each subset to serve different performance objectives simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different placement strategies are applied to different subsets of known bits based on their local optimization goals. The first subset receives early decoding position placement while the second subset receives least reliable position placement, allowing local optimization for both early termination and block error rate without compromising the other.

Inventive Principle:

Principle #3Local quality

2Reliability

If known bits are placed in least reliable decoding positions to improve block error rate, then error performance is enhanced, but early decoding termination performance deteriorates

Engineering Contradiction:

Improveblock error rateVSAvoiddecoding latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The known bits are divided into two subsets with distinct placement optimizations. The second subset is specifically placed in least reliable positions to enhance block error rate performance, while the first subset handles early termination optimization, preventing degradation of latency performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different placement strategies are applied locally to different subsets of known bits. The second subset receives specialized placement in least reliable positions for block error rate optimization, while the first subset maintains early termination benefits, achieving local optimization for both objectives.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If a single placement strategy is used for all known bits, then implementation is simple, but both early termination and block error rate cannot be optimized simultaneously

Engineering Contradiction:

Improveimplementation simplicityVSAvoidoverall performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The known bits are segmented into two subsets with distinct placement criteria. This segmentation enables simultaneous optimization of early termination and block error rate performance, achieving superior overall performance despite increased implementation complexity compared to single-strategy approaches.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different placement strategies are applied to different subsets of known bits based on their specific optimization goals. This local quality approach allows the system to achieve both early termination gain and improved block error rate performance simultaneously, optimizing overall performance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10944511B2Information bits for polar codes with mixed criteria

Publication Date: 2021.03.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

According to some embodiments, a method performed by a wireless device for polar encoding payload bits comprises: identifying payload bits of a data channel that have known values; placing a first subset of the known payload bits at input positions of a polar encoder that correspond to the earliest decoding bit positions of the polar encoder; placing a second subset of the known payload bits at input positions of the polar encoder that correspond to the least reliable decoding bit positions of the polar encoder after placement of the first subset of the known payload bits; and transmitting the polar encoded payload bits to a wireless receiver. The first subset of the known payload bits are placed in earliest decoding bit positions to improve early termination gain. The second subset of the known payload bits are placed in least reliable decoding bit positions to enhance error performance.