DRX Mobility Mode Switching for UE Power and Connectivity

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Solution Overview

Problem

In wireless network systems, user equipment (UE) in a long DRX mode within the CONNECTED state faces challenges with inaccurate mobility measurements and radio link failure detection, leading to potential handover failures and increased power consumption due to frequent receiver activations, which hinder battery preservation and data transmission.

Innovation Solution

The UE dynamically switches between network-controlled and UE-controlled mobility modes based on DRX parameter thresholds, adjusting measurement reporting frequencies to maintain connectivity and conserve power, allowing for longer sleep periods while ensuring accurate measurements and minimizing data outages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE frequently activates its receiver to perform measurements and provide measurement reports in long DRX mode, then measurement accuracy and mobility management are improved, but power consumption increases and battery preservation is compromised

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic switching between network-controlled mobility mode and UE-controlled mobility mode based on DRX parameter thresholds. When DRX parameters indicate long sleep periods, the UE switches to UE-controlled mode to reduce measurement frequency and power consumption. This dynamic adaptation resolves the contradiction by adjusting measurement behavior according to actual DRX configuration.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the mobility control parameter (network-controlled vs. UE-controlled mode) based on DRX parameter values. When DRX parameters exceed certain thresholds, the system transitions from network-controlled to UE-controlled mobility, thereby reducing measurement reporting frequency and power consumption while maintaining acceptable mobility performance.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If the UE switches to UE-controlled mobility mode to reduce power consumption, then battery preservation is improved, but connectivity reliability may deteriorate due to inaccurate mobility measurements

Engineering Contradiction:

Improvepower consumptionVSAvoidconnectivity reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The UE provides feedback to the network about its DRX parameters and mobility mode status. This feedback mechanism allows the network to understand the UE's power saving state and adjust network-controlled handover parameters accordingly, maintaining connectivity reliability even when UE-controlled mode is active.

Inventive Principle:

Principle #23Feedback

3Reliability

If the UE remains in network-controlled mobility mode to ensure accurate measurements, then connectivity reliability is improved, but the UE cannot achieve sufficient sleep periods and standby time is reduced

Engineering Contradiction:

Improveconnectivity reliabilityVSAvoidstandby time

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

4Measurement precision

If the UE provides frequent measurement reports to assist network-controlled handover, then handover accuracy is improved, but data transmission continuity is disrupted and outages increase

Engineering Contradiction:

Improvehandover accuracyVSAvoiddata outage time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies partial measurement reporting action by switching to UE-controlled mobility mode, where the UE performs measurements but does not provide frequent measurement reports to the network. This partial action is sufficient for UE-controlled cell reselection while reducing interruptions to data transmission and minimizing outages.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8688119B2Method, apparatus and system for mobility enhancement in DRX

Publication Date: 2014.04.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

When a user equipment (UE) is in a CONNECTED state with a base station of a wireless network and is also in a discontinuous reception (DRX) mode, a DRX parameter such as DRX period for the UE is compared with a threshold. If the DRX parameter is at or below the threshold, the UE applies a network controlled mobility mode with UE assist where the network controls handover of the UE to another cell. If the DRX parameter is above the threshold, the UE applies a UE controlled mobility mode in which the UE is free to select a best cell. In this way, DRX benefit of reduced power consumption is maintained while the time period in which the UE is unreachable is minimized.