Network Node Mobility Criterion Based on UL-DL Propagation Imbalance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current wireless communications networks face performance degradation due to large deviations in uplink and downlink link performance caused by path loss imbalances, leading to unnecessary mobility measures and potential handovers to lower-performing networks.

Innovation Solution

A network node determines a mobility criterion based on the imbalance between uplink and downlink propagation conditions, using information such as power control commands and UL Block Error Rate to adjust thresholds and prevent unnecessary handovers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mobility criteria are set conservatively to ensure good connectivity for all wireless communications devices, then reliability of connectivity is improved, but unnecessary mobility measures are triggered leading to performance degradation

Engineering Contradiction:
Improveconnectivity reliabilityVSAvoidnetwork performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the parameters used for mobility criteria from downlink-only measurements to a combination of downlink and uplink measurements. By introducing uplink measurements (UL BLER, power control commands) as new parameters, the system can more accurately assess actual link conditions and set appropriate mobility thresholds, reducing unnecessary handovers while maintaining connectivity reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback mechanisms where uplink performance measurements (UL BLER, power control adjustments) are continuously monitored and fed back to adjust mobility criteria. This closed-loop feedback allows the system to adapt mobility thresholds based on actual uplink conditions, preventing both unnecessary handovers and connectivity failures.

Inventive Principle:
Principle #23Feedback

2Device complexity

If downlink-only measurements are used for mobility criteria, then device complexity is reduced, but accuracy of mobility decision-making deteriorates due to path loss imbalances

Engineering Contradiction:
Improvemeasurement complexityVSAvoidmobility criterion accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges downlink and uplink measurements into a unified mobility assessment framework. By combining DL RSRP with UL BLER and power control command information, the system achieves more accurate mobility decisions that account for both directions of communication, resolving the issue of path loss imbalances that affect uplink but not downlink.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal mobility criterion that works for both symmetric and asymmetric link conditions. The multi-functional measurement approach can handle cases where downlink and uplink path losses differ, making the mobility decision-making accurate across various deployment scenarios without requiring separate criteria for different conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3266245B1A network node and a method therein for determining a mobility criterion
Publication Date: 2020.10.21 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3266245B1 patent drawingFigure 1
  • EP3266245B1 patent drawingFigure 2
  • EP3266245B1 patent drawingFigure 3

AI summary

A method performed by a network node for determining a mobility criterion related to a wireless communications device in a wireless communications network. The network node obtains (302) an information related to an UL propagation condition associated to the wireless communications device. The network node determines (303) a measure of imbalance between the UL propagation condition and a DL propagation condition associated to the wireless communications device. The measure of imbalance is based on the information related to the UL propagation condition. The network node determines (304) the mobility criterion based on the measure of imbalance between the UL propagation condition and the DL propagation condition.