Inter-Cell MAC Messaging for Fast SCG Reactivation

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Solution Overview

Problem

In wireless communication networks, particularly in multi-connectivity scenarios, deactivating a secondary cell group (SCG) to reduce UE energy consumption leads to increased delays during subsequent activation due to the UE refraining from monitoring the physical downlink control channel (PDCCH) of the SCG.

Innovation Solution

The UE transmits and receives MAC messages for the deactivated SCG through an activated master cell group (MCG), allowing it to prepare for reactivation without excessive delay by performing operations related to the SCG based on encapsulated MAC messages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the UE refrains from monitoring the PDCCH of the deactivated SCG to reduce energy consumption, then energy consumption is reduced, but activation delay increases

Engineering Contradiction:

ImproveUE energy consumptionVSAvoidSCG activation delay

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the UE maintain readiness to receive and process MAC messages for the deactivated SCG through the MCG, so that when activation is needed, the UE can quickly process messages without requiring continuous PDCCH monitoring. The UE prepares in advance by keeping the SCG configuration and message processing capability active, even though full monitoring is suspended.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the MCG as an intermediary channel to transmit MAC messages related to the deactivated SCG. Instead of requiring direct PDCCH monitoring on the SCG, the network sends messages through the MCG which then delivers them to the UE for SCG processing. This intermediary mechanism allows the UE to stay informed about SCG status without continuously monitoring the SCG's control channel.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the UE stops monitoring PDCCH on the deactivated SCG, then energy consumption is reduced, but the ability to quickly reactivate SCG is compromised

Engineering Contradiction:

ImproveUE energy consumptionVSAvoidSCG reactivation readiness

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The UE performs preliminary actions by maintaining the SCG configuration and processing capability in a ready state, allowing immediate activation when needed. The UE prepares in advance by keeping the necessary software components and message handling structures active, so that when activation occurs, there is no delay for initialization.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The MCG serves as an intermediary that maintains communication continuity for the deactivated SCG. By sending MAC messages through the MCG, the network ensures the UE remains informed about SCG status and can quickly reactivate without losing readiness, thus maintaining reliability while reducing energy consumption.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of time

If the UE monitors PDCCH continuously on the SCG, then activation delay is minimized, but energy consumption increases

Engineering Contradiction:

ImproveSCG activation delayVSAvoidUE energy consumption

Core Design Contradiction:

Loss of timeVSUse of energy by moving object

Solution Approach 1:

Instead of continuous monitoring, the patent implements periodic or event-driven message reception through the MCG. The UE monitors for SCG-related messages at appropriate intervals or when triggered by network events, rather than continuously scanning the PDCCH. This periodic approach reduces energy consumption while maintaining adequate activation readiness.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The MCG acts as an intermediary that delivers SCG messages to the UE periodically or on-demand, eliminating the need for continuous PDCCH monitoring. This intermediary channel provides just enough information for quick activation without requiring constant monitoring, thus reducing energy consumption while maintaining low activation delay.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12549977B2Inter-cell group messages for user equipment operating in multi-connectivity

Publication Date: 2026.02.10 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Methods and apparatus for a user equipment, UE, configured for dual connectivity, DC, with a wireless network via a first node arranged to provide a first cell group and a second node arranged to provide a second cell group. Such methods and apparatuses include receiving (1620) a first medium access control, MAC, message from the first node by a first UE MAC entity associated with the first cell group, and determining (1630) that the first MAC message includes an encapsulated second MAC message for a second UE MAC entity associated with the second cell group, which is deactivated. Such methods and apparatuses also include performing (1640) one or more operations related to the second cell group based on the second MAC message.