Conditional Handover Execution with Network Feedback Control

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Solution Overview

Problem

Conditional handover procedures in wireless communication networks face challenges such as increased signaling overhead, radio resource waste, and unpredictable user equipment (UE) behaviors, leading to service interruptions and loss of network control due to rapid serving cell quality degradation and blockages, especially in 5G networks with massive antenna beamforming.

Innovation Solution

A method where user equipment (UE) receives and stores conditional handover (CHO) commands from a source base station, evaluates triggering conditions, and transmits notifications to the source base station, allowing for controlled execution of CHO commands, including options to wait for confirmation or execute based on a response timer, thereby reducing service interruptions and maintaining network controllability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the UE autonomously executes CHO commands without network notification, then handover execution speed is improved, but network controllability deteriorates

Engineering Contradiction:
Improvehandover execution speedVSAvoidnetwork controllability
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism where the UE sends a CHO notification message to the network when triggering conditions are met. The network responds with confirmation or cancellation instructions, creating a closed-loop control system that maintains network controllability while enabling fast autonomous execution upon approval.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent establishes preliminary agreements between the network and UE regarding CHO execution protocols. The network pre-configures measurement thresholds and CHO commands, and pre-establishes the notification-feedback mechanism, allowing the UE to execute handovers autonomously when conditions are met without real-time network intervention.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the UE sends measurement reports early for CHO preparation, then handover readiness is improved, but signaling overhead increases

Engineering Contradiction:
Improvehandover readinessVSAvoidsignaling overhead
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent changes the triggering parameters for measurement reports by using relaxed thresholds specifically for CHO preparation purposes. This allows earlier detection of potential target cells with reduced signaling frequency compared to conventional handover reporting, balancing readiness preparation with overhead reduction.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the network reserves resources for multiple potential target cells, then handover success rate is improved, but radio resource waste increases

Engineering Contradiction:
Improvehandover success rateVSAvoidradio resource waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by reserving radio resources selectively only for specific target cells that have been identified as potential handover destinations based on UE measurement reports and relaxed thresholds. Resources are allocated locally to relevant target cells rather than universally across all possible targets, reducing overall resource waste while maintaining handover success rate.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3738347B1Conditional handover procedures
Publication Date: 2023.12.20 FG INNOVATION CO LTD
  • EP3738347B1 patent drawingFigure 1
  • EP3738347B1 patent drawingFigure 2
  • EP3738347B1 patent drawingFigure 3

AI summary

A method for a conditional handover (CHO) is disclosed. The method may receive from a source base station (e. g., a gNB or an eNB) one or more CHO commands that each is associated with one or more triggering conditions for a CHO to a target cell associated with a target base station (e. g., a target gNB or a target eNB). The method may continuously evaluate the triggering condition (s) associated with each received (and valid) CHO command. When the method determines that at least one of the triggering conditions has been fulfilled, the method may execute the CHO command that is associated with the triggering condition in order to connect to one or more candidate target cells associated with the CHO command.