Physical Broadcast Channel Extension for Reduced-Capability UE Coverage

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Solution Overview

Problem

Reduced capability UEs in wireless communication networks face challenges in obtaining system information due to coverage limitations, particularly in cellular networks like 5G NR, leading to connectivity issues.

Innovation Solution

The introduction of an extended physical broadcast channel (EPBCH) with repeated transmissions during an extension window, allowing for flexible scheduling and mapping to resources within the channel to enhance coverage and reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If legacy PBCH transmission is used, then device compatibility is maintained, but coverage is limited for reduced capability UEs

Engineering Contradiction:

Improveconnectivity reliabilityVSAvoidcoverage limitation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The PBCH transmission is segmented into legacy PBCH blocks and extended PBCH blocks, where legacy blocks maintain compatibility with existing UEs while extended blocks provide enhanced coverage for reduced capability UEs. The extension window contains additional PBCH blocks that repeat or supplement the legacy transmission, allowing UEs to accumulate signals from multiple blocks to improve reception reliability in coverage-limited scenarios.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The extended PBCH transmission employs periodic repetition of system information across multiple PBCH blocks within an extension window. This periodic action allows reduced capability UEs to receive and decode system information through cumulative signal accumulation over multiple transmission instances, effectively extending coverage while maintaining compatibility with legacy UEs that can still decode the original legacy PBCH blocks.

Inventive Principle:

Principle #19Periodic action

2Reliability

If PBCH repetition number is increased to extend coverage, then coverage is improved, but transmission time and resource consumption increase

Engineering Contradiction:

ImprovecoverageVSAvoidtransmission time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system dynamically configures the extension window size and PBCH repetition number based on network conditions and UE capabilities. The extension window can be adaptively adjusted to provide just enough repeated transmissions for reduced capability UEs to decode system information, avoiding unnecessary time consumption for UEs that do not require extended coverage. This dynamic approach balances coverage extension with transmission efficiency.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12439432B2Physical broadcast channel extension in wireless communications

Publication Date: 2025.10.07 APPLE INC

AI summary

To extend a physical broadcast channel (PBCH) in wireless communications, an extended physical broadcast channel (EPBCH) transmission is generated with one or more legacy PBCH blocks and one or more EPBCH blocks within an extension window. A size of the extension window is determined based at least in part on a PBCH repetition number and a number of the legacy PBCH blocks relative to a number of the EPBCH blocks. The EPBCH transmission is transmitted by a base station (BS) to one or more user equipment (UE).