RedCap UE Scheduling With Split DCI for Lower PDCCH Latency

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Solution Overview

Problem

Existing 5G NR networks face challenges in efficiently managing reduced capability (RedCap) UEs due to increased PDCCH blocking probability and latency issues resulting from reduced monitoring of the Physical Downlink Control Channel, which are exacerbated by smaller form factors and battery constraints in devices like wearables and industrial sensors.

Innovation Solution

The downlink and uplink scheduling information is divided into a common DCI portion and a UE-specific DCI portion, transmitted on different physical channels, with separate encoding and CRC attachments, using group-common RNTIs for RedCap devices to reduce power consumption and latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If RedCap UEs reduce monitoring of PDCCH to save power, then power consumption is reduced, but latency increases and scheduling efficiency deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidlatency

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The scheduling information is segmented into two parts: common scheduling information transmitted via group-common PDCCH that multiple RedCap UEs can monitor efficiently, and UE-specific scheduling information transmitted via dedicated PDCCH. This segmentation allows RedCap UEs to monitor the common channel with reduced power while still receiving timely scheduling assignments through the dedicated channel when needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

RedCap UEs perform periodic monitoring of the group-common PDCCH at configured intervals rather than continuously monitoring all PDCCH opportunities. This periodic monitoring approach reduces power consumption while maintaining acceptable latency performance by balancing the monitoring frequency with the traffic patterns and QoS requirements.

Inventive Principle:

Principle #19Periodic action

2Volume of moving object

If RedCap UEs use smaller form factors and reduced capabilities, then device size and cost are reduced, but PDCCH blocking probability increases

Engineering Contradiction:

Improvedevice sizeVSAvoidPDCCH blocking probability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The control channel resources are segmented into group-common PDCCH resources shared by multiple RedCap UEs and UE-specific PDCCH resources dedicated to individual UEs. This segmentation reduces PDCCH blocking probability for RedCap UEs by providing alternative scheduling paths - if dedicated resources are blocked, the UE can still receive scheduling information through the group-common channel.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The group-common PDCCH serves multiple functions: it provides scheduling information for multiple RedCap UEs simultaneously, acts as a fallback when UE-specific PDCCH is blocked, and enables efficient resource utilization by allowing one PDCCH transmission to serve multiple UEs. This multi-functionality improves reliability without requiring larger device form factors.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If scheduling information is transmitted using traditional UE-specific DCI only, then scheduling accuracy is maintained, but power consumption and latency increase for RedCap UEs

Engineering Contradiction:

Improvescheduling accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Scheduling information is segmented into common parameters (e.g., resource allocation, modulation scheme) transmitted via group-common DCI that apply to multiple UEs, and UE-specific parameters (e.g., HARQ process, redundancy version) transmitted via UE-specific DCI. This segmentation allows RedCap UEs to efficiently decode the common part with reduced power while maintaining accurate scheduling through the UE-specific part.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges group-common DCI and UE-specific DCI into a unified scheduling framework where both parts work together to provide complete scheduling information. The group-common DCI provides the bulk of scheduling parameters that can be shared, while the UE-specific DCI provides the final customization needed for accurate scheduling, achieving both power efficiency and scheduling accuracy.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250280421A1Network Data Scheduling and Transmission for Reduced Capability UEs

Publication Date: 2025.09.04 APPLE INC

AI summary

A base station of a wireless network transmits scheduling information to a user equipment (UE). The base station divides scheduling information for the UE into a common downlink control information (DCI) portion and a UE-specific DCI portion, encodes the common DCI portion for transmission on a first physical resource, encodes the UE-specific DCI portion for transmission on a second physical resource, transmits the encoded common DCI portion on the first physical resource and transmits the encoded UE-specific DCI portion on the second physical resource.