Second Cell Group Dormancy Control for Lower UE Power

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Solution Overview

Problem

Dual connectivity in 5G networks leads to increased UE power consumption due to continuous scanning of wide carriers, especially in frequency range 2 (FR2), which is inefficient and costly in terms of energy usage.

Innovation Solution

Implementing bandwidth part (BWP) management and dormant state transitions for secondary cells (SCells) to optimize power consumption by dynamically adjusting active BWPs and reducing unnecessary scanning, combined with UE assistance information for power-saving preferences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If dual connectivity is implemented with continuous scanning of wide carriers in FR2, then data rate and network coverage are improved, but UE power consumption increases significantly

Engineering Contradiction:

Improvedata rateVSAvoidUE power consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic BWP switching where the UE can transition between different BWPs (including dormant and non-dormant states) based on data activity and network conditions. This allows the system to adapt the scanning and monitoring behavior dynamically - using wide carriers when data transmission is active and reducing to narrower or dormant BWPs when idle, thereby resolving the contradiction between maintaining high data rates and reducing power consumption during continuous operation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent introduces periodic BWP inactivity timers that trigger transitions between active and dormant states. Instead of continuous wide carrier scanning, the UE performs scanning periodically or only when triggered by data arrival, allowing power savings during idle periods while maintaining the capability to quickly resume high-speed data transmission when needed, thus balancing data rate requirements with power consumption

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If bandwidth part (BWP) management and dormant state transitions are implemented, then UE power consumption is reduced, but system complexity increases

Engineering Contradiction:

ImproveUE power consumptionVSAvoidsystem complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent segments the carrier bandwidth into multiple BWPs with different characteristics (dormant, active, wide, narrow). Each BWP can be independently configured and activated based on specific conditions. This segmentation allows the system to manage complexity by handling smaller, discrete bandwidth portions separately rather than managing the entire wide carrier continuously, reducing the overall system complexity while enabling power savings

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes key parameters such as BWP bandwidth, subcarrier spacing, and cyclic prefix length based on operational state and traffic requirements. By dynamically adjusting these parameters through BWP switching, the system reduces complexity in maintaining continuous wide carrier monitoring while preserving the ability to achieve high data rates when needed, effectively managing the trade-off between power consumption and system complexity

Inventive Principle:

Principle #35Parameter changes

3Reliability

If continuous monitoring of all serving cells is performed, then connection reliability is improved, but power consumption increases

Engineering Contradiction:

Improveconnection reliabilityVSAvoidUE power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements partial monitoring where the UE monitors only a subset of serving cells or only specific BWPs within serving cells during dormant states, rather than continuously monitoring all cells at full detail. This partial action maintains sufficient connection reliability for critical functions while significantly reducing power consumption during idle periods, resolving the contradiction between reliability and power usage

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12507084B2UE triggered second cell group suspension/dormancy/deactivation/resumption

Publication Date: 2025.12.23 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method performed by a wireless terminal operating in Multi-Radio Dual Connectivity (MR-DC) and configured with a first cell group associated with a first network node and a second cell group associated with a second network node and a wireless terminal is provided. The method includes monitoring conditions and events for indicating that an operating mode of the second cell group should be modified. The method includes transmitting an indication to a network requesting a modification for the operating mode of the second cell group responsive to the monitoring indicating the operating mode of the second cell group should be modified. The method includes receiving a command from the network to change the operating mode of the second cell group. The method includes responsive to receiving the command, applying the command and start operating the second cell group in the indicated operating mode.