Radio Link Monitoring Configuration for Wireless Devices

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Solution Overview

Problem

The existing design for radio link monitoring (RLM) in wireless communication networks, particularly in enhanced machine type communication (eMTC) and narrowband IoT (NB-IoT), tends to trigger unnecessary radio link failures (RLF) as devices move towards cell edges, leading to resource wastage and energy consumption, due to the use of a highest configured physical downlink control channel (PDCCH) repetition and aggregation level that may not be necessary for all locations within a cell.

Innovation Solution

The network informs user equipment (UE) about the maximal PDCCH/NPDCCH repetition and aggregation level supported in the cell, allowing the UE to use this configuration for RLM and RLF triggering, either always or conditionally, with the option to switch to the maximum level when data transmission is not active or after a specified inactivity timer expires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the highest configured PDCCH repetition and aggregation level is used for radio link monitoring, then the monitoring coverage is improved, but unnecessary radio link failures are triggered and resources are wasted

Engineering Contradiction:
Improveradio link monitoring coverageVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the PDCCH repetition and aggregation level configurable and switchable based on UE activity state. The network can dynamically adjust the monitoring level between highest configured level (for inactive UEs) and a lower level (for active UEs), allowing the system to adapt its behavior to current operational conditions rather than using a fixed high level always

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of PDCCH repetition and aggregation level from a fixed highest value to a variable parameter that can be adjusted based on UE activity. By introducing an activity-based configuration mechanism, the system can switch between different parameter sets (highest level vs. lower level) to optimize both reliability and energy consumption depending on whether the UE is active or inactive

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the highest configured PDCCH repetition and aggregation level is used for radio link monitoring, then the monitoring coverage is improved, but radio resources are wasted

Engineering Contradiction:
Improveradio link monitoring coverageVSAvoidradio resources
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent makes the resource consumption dynamic by adjusting the PDCCH monitoring level according to UE activity state. When UE is inactive, the highest configured level is used for comprehensive monitoring; when UE is active, a lower level is sufficient, thereby dynamically optimizing resource utilization rather than continuously consuming maximum resources

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the monitoring parameter from a constant highest level to a variable level that adapts to traffic conditions. This parameter adjustment mechanism allows the network to reduce radio resource consumption during active data transmission when lower monitoring levels are adequate, while maintaining high monitoring coverage during inactive periods

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a fixed highest PDCCH repetition level is used, then the configuration is simple, but it cannot adapt to different UE locations and activity states

Engineering Contradiction:
Improveconfiguration complexityVSAvoidadaptability to UE location and activity
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adaptability through activity-based configuration, where the PDCCH monitoring level automatically adjusts based on UE activity state detected by the network. This adds adaptability without significantly increasing complexity, as the adjustment logic is triggered by observable activity patterns rather than requiring complex location-based or prediction-based mechanisms

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements parameter adaptation by changing the PDCCH repetition and aggregation level based on UE activity state. The network monitors UE activity and switches between parameter sets (highest level for inactive, lower level for active), providing adaptability to different operational conditions while maintaining relatively simple configuration management

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3602880B1Enhanced radio link monitoring for user equipment
Publication Date: 2023.04.12 NOKIA TECHNOLOGIES OY
  • EP3602880B1 patent drawingFigure 1
  • EP3602880B1 patent drawingFigure 2a~2b
  • EP3602880B1 patent drawingFigure 3a

AI summary

Systems, methods, apparatuses, and computer program products for enhanced radio link monitoring (RLM) are provided. One method may include signaling, by a network node, information to at least one user equipment. The information may include an indication of a maximum number of physical downlink control channel repetition and aggregation level(s). The indication may be independent from the physical downlink control channel repetition and aggregation level that the at least one user equipment is configured to monitor for data transfer.