Conditional PCell Mobility for MCG Failure Recovery
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Solution Overview
Problem
In wireless communication systems, handling master cell group (MCG) failures during dual connectivity is inefficient, leading to time and resource wastage due to late inter-node signaling between old and new primary cells, preventing the user equipment (UE) from transmitting new data.
Innovation Solution
A method and apparatus for handling MCG failure by receiving a conditional mobility command, starting a timer for MCG failure recovery, transmitting MCG failure information to a secondary cell, and performing a random access to a target primary cell upon satisfaction of mobility conditions, thereby reducing data interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transmits MCG failure information to the PSCell after detecting RLF on the source PCell, then the MCG failure is reported to the network, but inter-node signaling between old and new primary cells is delayed, causing data interruption
Solution Approach 1:
The UE performs mobility to the target PCell in advance based on a conditional mobility command before the MCG failure is fully processed, so that when failure information is transmitted, the UE is already connected to the new cell, eliminating data interruption
Solution Approach 2:
The target PCell acts as an intermediary that receives data forwarding from the source PCell during the mobility transition, ensuring continuous data flow while the UE switches cells, thereby reducing data interruption time
2Reliability
If the UE waits for inter-node signaling completion before mobility, then network coordination is ensured, but resource utilization is reduced due to delayed data transmission
Solution Approach 1:
The UE executes mobility to the target PCell before inter-node signaling is complete, based on pre-configured conditional mobility commands, allowing data transmission to resume immediately while network coordination continues in the background
Solution Approach 2:
Data forwarding is established between source and target PCells during the mobility transition, ensuring continuous data flow and maintaining resource utilization while the UE switches cells
Data Source
AI summary
The present disclosure relates to handling a master cell group (MCG) failure in wireless communications. According to an embodiment of the present disclosure, a method performed by a wireless device in a wireless communication system comprises: receiving, from a source primary cell (PCell), a conditional mobility command including a mobility condition for a target PCell; starting a timer for a master cell group (MCG) failure recovery and transmitting MCG failure information related to the MCG failure recovery to a primary secondary cell (PSCell), based on detecting a radio link failure (RLF) on the source PCell; and based on that the mobility condition for the target PCell is satisfied while the timer is running: transmitting, to the PSCell, a new PCell indication informing a mobility from the source PCell to the target PCell; and performing a random access to the target PCell for the mobility.