NB-IoT DRX Paging With UE-Specific Cycles for Lower Latency

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Solution Overview

Problem

Existing NB-loT systems struggle to provide reduced latency for devices in good coverage while maintaining compatibility with legacy systems and avoiding increased power consumption and resource congestion.

Innovation Solution

Introduction of UE-specific DRX cycles with shorter durations for devices in good coverage, along with separate carrier mappings and configurations to optimize resource allocation and minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a single long DRX cycle is used for all NB-loT devices, then energy efficiency is improved for devices in bad coverage, but latency increases for devices in good coverage requiring reduced latency services

Engineering Contradiction:
Improveenergy efficiencyVSAvoidlatency
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent segments the NB-loT device population into two groups: devices in bad coverage using a long DRX cycle for energy efficiency, and devices in good coverage using a short DRX cycle for reduced latency. This segmentation allows each group to operate with optimized DRX parameters suited to their specific requirements, resolving the contradiction between energy efficiency and latency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic DRX cycle configuration where the network can assign different DRX cycle lengths to different UEs based on their coverage conditions and service requirements. This dynamic adaptation allows the system to switch between long and short DRX cycles, enabling devices to transition between energy-saving mode and low-latency mode as needed.

Inventive Principle:
Principle #15Dynamics

2Loss of time

If UE-specific short DRX cycles are introduced for devices in good coverage, then latency is reduced, but system complexity increases due to multiple DRX configurations

Engineering Contradiction:
ImprovelatencyVSAvoidsystem complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing UE-specific DRX configurations only where needed (for devices in good coverage requiring reduced latency services), while maintaining the standard long DRX cycle for devices in bad coverage. This localized application of short DRX cycles minimizes the impact on overall system complexity while achieving latency reduction for specific device groups.

Inventive Principle:
Principle #3Local quality

3Productivity

If separate paging carriers are used for short DRX UEs, then resource allocation is optimized and interference is minimized, but device complexity increases

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces a new dimension for resource allocation by assigning different paging carriers to short DRX UEs versus standard UEs. This dimensional separation in the frequency domain allows the system to optimize resource allocation and minimize interference between the two device groups, while the complexity increase is managed through standardized carrier configuration procedures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3868153B1Discontinuous reception in internet of things applications
Publication Date: 2026.02.18 JRD COMM (SHENZHEN) LTD
  • EP3868153B1 patent drawingFigure 1
  • EP3868153B1 patent drawingFigure 2
  • EP3868153B1 patent drawingFigure 3

AI summary

NB-IoT offers a communication standard for IoT devices in a cellular network. Techniques for providing efficient spectrum management and timely paging of NB-IoT devices are disclosed, including specific DRX cycles for sets of devices in good coverage which require lower latency paging than provided by standard DRX cycles.