SCG Downlink Synchronization for Fast Dual-Connectivity Activation
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Solution Overview
Problem
In 5G networks with dual connectivity, the activation delay of a deactivated secondary cell group (SCG) is significant due to the need for re-establishing downlink synchronization, leading to increased power consumption and latency.
Innovation Solution
The UE maintains downlink synchronization with the SCG by tracking synchronization signals and frame timing, allowing immediate activation upon command, thereby reducing the need for re-synchronization during activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the SCG is deactivated to save power, then power consumption is reduced, but activation delay increases due to re-synchronization requirements
Solution Approach 1:
The patent applies preliminary action by having the UE maintain downlink synchronization with the SCG in advance while it is deactivated. The UE continues to track synchronization signals and frame timing information even when the SCG is inactive, so that when activation is needed, the UE is already synchronized and can immediately communicate without requiring re-synchronization. This preliminary maintenance of synchronization state resolves the contradiction by enabling fast activation while preserving power savings during deactivated periods.
2Loss of time
If the SCG is kept activated to maintain synchronization, then activation delay is reduced, but power consumption increases
Solution Approach 1:
Instead of keeping the SCG continuously activated, the patent uses preliminary action by maintaining synchronization information in advance during deactivated periods. The UE tracks synchronization signals and timing while the SCG is deactivated, preparing the synchronization state ahead of time. This allows the SCG to be quickly activated without requiring continuous active maintenance, thus reducing power consumption while still achieving fast activation when needed.
3Reliability
If full re-synchronization is performed during SCG activation, then synchronization reliability is ensured, but activation time increases
Solution Approach 1:
The patent applies preliminary action by maintaining synchronization state in advance while the SCG is deactivated. The UE continues to track synchronization signals and frame timing information, so that when activation occurs, the UE is already synchronized. This eliminates the need for full re-synchronization during activation, ensuring both synchronization reliability and fast activation time.
Solution Approach 2:
The patent applies continuity of useful action by having the UE continuously track synchronization signals and maintain timing information even when the SCG is deactivated. This continuous maintenance of synchronization state ensures that synchronization reliability is preserved without requiring repeated re-synchronization operations during activation, thus avoiding time loss.
Data Source
AI summary
A communication device can be configured to operate in dual connectivity (DC) with a first node via a first cell group and at least one second node via a second cell group. The communication device can synchronize with the second cell group while the second cell group is in a power saving mode of operation. The communication device can determine that the second cell group is switching to an activated mode of operation. Responsive to determining that the second cell group is switching to the activated mode of operation, the communication device can transmit a message to the second node via the second cell group at a next available transmission occasion.