LTM Configuration via RRC for Faster Inter-gNB Mobility Handover
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Solution Overview
Problem
Existing 5G wireless communication systems face challenges in managing increased communication traffic and efficiently handling mobility between different base stations, particularly in inter-gNB-CU scenarios, leading to increased interruption times due to the reliance on layer 3-based handovers.
Innovation Solution
A method and apparatus for configuring Layer 1/Layer 2 Triggered Mobility (LTM) that enables seamless handovers between different base stations by using unique LTM candidate cell identities and configurations, facilitated through radio resource control (RRC) messaging, to support efficient inter-gNB-CU mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If layer 3-based handovers are used for inter-gNB-CU mobility, then handover procedure is simplified, but handover interruption time increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring LTM candidate cells and their identities before actual handover occurs. The source gNB-CU requests and receives LTM candidate cell information from the target gNB-CU in advance, storing this configuration in the UE. This preparation eliminates the need for time-consuming layer 3 handover procedures while maintaining fast handover execution, thus reducing handover interruption time without complicating the overall procedure.
Solution Approach 2:
The patent changes the handover mechanism from layer 3-based to layer 1/layer 2-based by introducing LTM (Layer 1/2 Triggered Mobility). This parameter change involves using physical cell identities and LTM candidate cell configurations instead of traditional layer 3 handover signaling, enabling faster handover execution with reduced interruption time while maintaining operational simplicity through standardized RRC messaging.
2Productivity
If LTM is extended to inter-different base stations/gNB-CU, then mobility management efficiency improves, but system complexity increases
Solution Approach 1:
The patent applies universality by designing a unified LTM configuration mechanism that works across both intra-gNB-CU and inter-gNB-CU scenarios. The same RRC messaging and LTM candidate cell configuration process is used regardless of whether the handover is within the same base station or between different gNB-CUs, thereby improving mobility management efficiency without proportionally increasing system complexity.
Solution Approach 2:
The patent uses RRC (Radio Resource Control) messaging as an intermediary mechanism to manage LTM configuration between gNB-CUs and UEs. This standardized intermediary layer simplifies the interaction between different network elements, enabling efficient inter-gNB-CU mobility management while keeping the system architecture manageable through established protocol frameworks.
3Speed
If unique LTM candidate cell identities are used for inter-gNB-CU mobility, then handover speed increases, but configuration complexity increases
Solution Approach 1:
The patent changes the identification parameter from traditional layer 3 handover identifiers to physical cell identities and LTM candidate cell identities at the layer 1/layer 2 level. This parameter change enables faster handover execution by using more direct and compact identification mechanisms, while the configuration complexity is managed through standardized RRC messaging that handles the complexity automatically.
Data Source
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AI summary
Disclosed are a method and apparatus for configuring a layer 1 (L1)/layer 2 (L2) triggered mobility (LTM) in a wireless communication system. A source base station transmits a handover request message including an LTM information request to a target base station, receives a handover request acknowledge message including an LTM information response from the target base station, and transmits at least a portion of the received LTM information response to a UE through a radio resource control (RRC) message.