L1/L2 Mobility Preparation for Intra-Base Station CU-UP Relocation
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Solution Overview
Problem
Current cellular networks experience longer latency and interruption times due to layer 3-triggered mobility for intra-base station centralized unit user plane (CU-UP) relocation, leading to inefficiencies in UE service continuity.
Innovation Solution
Implementing layer 1/layer 2 triggered mobility (LTM) for intra-base station CU-UP relocation by preparing a target CU-UP and DU, including security key fetching and data forwarding, to enable seamless UE relocation between CU-UPs within a base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If layer 3-triggered mobility is used for intra-base station CU-UP relocation, then service continuity is maintained, but latency and interruption time increase
Solution Approach 1:
The patent applies preliminary action by preparing the target CU-UP and DU in advance before actual UE relocation occurs. The target resources are pre-configured with necessary security keys and contextual information, so that when relocation is triggered, the UE can switch immediately without waiting for resource setup, thus reducing latency while maintaining service continuity
Solution Approach 2:
The patent segments the mobility management process into distinct phases: resource preparation phase (where target CU-UP and DU are pre-configured) and execution phase (where actual handover occurs). This segmentation allows the time-consuming preparation work to be done in advance, separating it from the critical path of actual relocation, thereby reducing interruption time
2Reliability
If layer 3-triggered mobility is used for CU-UP relocation, then UE service continuity is maintained, but overhead increases
Solution Approach 1:
The patent extracts the resource preparation activities from the main handover signaling path. By preparing target CU-UP and DU resources separately in advance through internal base station interfaces, the patent removes the need for extensive layer 3 signaling exchanges during actual relocation, thereby reducing protocol overhead while maintaining service continuity
Data Source
AI summary
In general, the current subject matter relates to layer 1/layer 2 (L1/L2) triggered mobility (LTM) for intra-base station centralized unit user plane (CU-UP) relocation. In some implementations, a target distributed unit (DU) of a base station to serve a user equipment (UE) can be determined to be served by a target CU-UP of the base station. A serving CU-UP of the base station can serve a serving DU of the base station that is currently serving the UE. Using a centralized unit control plane (CU-CP) of the base station, the target CU-UP can be prepared for layer 1/layer 2 triggered mobility (LTM), and, using the CU-CP, the target DU can be prepared for LTM.