L1 Beam Measurement Configuration for Lower-Layer Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing L1/2 inter-cell mobility in 5G/NR networks faces challenges with high signaling overhead and mobility failures due to inadequate synchronization signal block (SSB) index updates, especially when multiple target cells are involved, which conventional methods struggle to address efficiently and reliably.
Innovation Solution
A network node, such as a CU-CP or L3 protocol, determines associations between target cell identifiers and shorter identifiers, transmitting configuration messages to UE for beam measurements without relying on SSB indices, allowing UE to decide on its own SSB indices for reporting, thereby reducing signaling overhead and improving mobility management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the network continuously updates the CSI-SSB-ResourceSet to include new SSB indices for L1/2 inter-cell mobility, then the measurement coverage is improved, but the signaling overhead increases
Solution Approach 1:
The patent extracts the essential identification function from the full SSB index list. Instead of transmitting the complete CSI-SSB-ResourceSet with all SSB indices, the network only transmits the cell identifier and a flag indicating that the UE should measure all SSB indices in the target cell. This extraction of critical information reduces signaling overhead while maintaining measurement coverage.
Solution Approach 2:
The patent enables the UE to autonomously determine which SSB indices to measure based on the received cell identifier and its local configuration. The UE uses its own capability information and the target cell's identifier to self-determine the measurement scope, eliminating the need for the network to explicitly list all SSB indices in the configuration messages.
2Speed
If the network updates the CSI-SSB-ResourceSet frequently to adapt to UE mobility, then the mobility responsiveness is improved, but the reliability of existing radio link decreases
Solution Approach 1:
The patent performs preliminary configuration of the UE with multiple target cells and their identifiers before actual mobility occurs. The UE stores this information locally and can immediately use it when mobility conditions arise, without requiring real-time updates. This pre-preparation enables fast response to mobility events while avoiding frequent signaling that could destabilize the current radio link.
3Measurement precision
If the UE measures all SSB indices in target cells for comprehensive beam management, then the measurement accuracy is improved, but the processing complexity increases
Solution Approach 1:
The patent segments the measurement task into two parts: (1) the network provides the cell identifier and measurement indication, and (2) the UE autonomously identifies and measures the relevant SSB indices based on its local configuration and the target cell's characteristics. This segmentation allows the UE to maintain comprehensive measurement capability while reducing the complexity of receiving and processing extensive network configurations.
Data Source
AI summary
Described herein is a first network node that supports at least one of central unit control plane (CU-CP) functionality or a layer 3 protocol of a radio access network, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first network node at least to: determine to prepare a target cell of a third network node for lower layer mobility (LLM) with a source cell of a second network node, wherein each of the second network node and the third network node supports at least one of the distributed unit (DU) functionality or a layer 2 protocol of the radio access network; obtain an association between a cell identifier of the target cell and a first identifier; and transmit a configuration message comprising information indicative of the association between the cell identifier of the target cell and the first identifier to a user equipment (UE) served by the source cell.