NR PBCH Bit Ordering for Lower-Latency Polar Decoding

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Solution Overview

Problem

Existing polar code implementations for NR PBCH in 5G wireless communication systems do not effectively exploit known or partially known bits, leading to suboptimal decoding performance and increased latency.

Innovation Solution

Strategically position known or partially known bits and introduce parity check bits in the Polar encoder to enhance decoding efficiency, using a known-bit interleaver and parity check bit generation methods to improve error performance and enable early termination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If known or partially known bits are not strategically positioned in the Polar encoder, then the decoding process must process all bits equally, but this leads to suboptimal decoding performance and increased latency

Engineering Contradiction:

Improvedecoding performanceVSAvoiddecoding latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by strategically positioning known or partially known bits at specific locations in the Polar encoder before decoding occurs. The known-bit interleaver pre-arranges these bits at positions that enable the decoder to exploit their known values during the decoding process, allowing for early termination and improved performance without increasing complexity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by treating known bits differently from unknown bits through the known-bit interleaver. Instead of uniform processing, the system identifies specific locations where known bits are placed and designs the decoding process to exploit this local knowledge, creating different processing paths for different bit positions based on their reliability characteristics

Inventive Principle:

Principle #3Local quality

2Reliability

If standard Polar coding is used without parity check bits, then the encoder structure remains simple, but error performance is suboptimal

Engineering Contradiction:

Improveerror performanceVSAvoidencoder structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the encoded bit sequence into information bits and parity check bits. The parity check bits are generated separately based on the information bits and then concatenated to form the final encoded sequence. This segmentation allows the system to maintain the simplicity of Polar coding while adding error detection capabilities through the separate parity check bit generation process

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250300764A1Bit Order of NR PBCH Payload to Enhance Polar Code Performance

Publication Date: 2025.09.25 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Systems and methods are described herein that allow information carrying bits of a transmission block to be placed at higher-reliability positions prior to transmission. An exemplary method includes generating a set of payload bits to be encoded for transmission, wherein the set of payload bits includes at least one known bit, interleaving the set of payload bits to generate an interleaved set of payload bits, wherein the interleaved set includes the at least one known bit in a predetermined position in the interleaved set, providing the interleaved set to a cyclic redundancy check (CRC) encoder to generate CRC-interleaved set of payload bits, wherein the CRC-interleaved set includes the at least one known bit in a predetermined position within the CRC-interleaved set, and encoding the CRC-interleaved set for transmission to a wireless device. Associated network nodes and wireless devices are included.