User Equipment SpCell Activation via MAC Signaling for Mobility
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Solution Overview
Problem
Existing 5G NR specifications do not support inter-cell beam switching without RRC signaling, limiting the ability to efficiently manage SpCells and reducing mobility interruptions.
Innovation Solution
A method for configuring User Equipment (UE) with a set of SpCell configurations and using lower layer signaling, such as MAC CEs, to activate or deactivate SpCells, allowing inter-cell mobility without RRC involvement, by associating TCI states to different SpCells and using cell indexes for efficient signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RRC signaling is used for inter-cell beam switching, then reliability of connection is improved, but signaling delays and mobility interruptions increase
Solution Approach 1:
The patent segments the mobility management function by introducing a new MAC CE command structure that operates independently from RRC signaling. The MAC CE Layer 2 control element handles beam switching at the MAC layer, separating this function from the higher-layer RRC protocol, thereby reducing signaling delays while maintaining connection reliability through layered protocol design
Solution Approach 2:
The patent introduces an intermediary MAC CE command as a mediator between the physical layer beam management and the RRC layer. This MAC CE acts as an intermediate control mechanism that enables fast beam switching without requiring full RRC reconfiguration, thus reducing signaling delays while preserving connection integrity through the intermediary control plane
2Manufacturing precision
If RRC signaling is used for SpCell configuration, then configuration accuracy is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent extracts the SpCell activation/deactivation function from the complex RRC signaling framework and implements it as a dedicated MAC CE command. This extraction removes the burden of extensive RRC message exchange for routine SpCell management, reducing signaling overhead and device complexity while maintaining configuration accuracy through the specialized MAC layer command structure
Solution Approach 2:
The patent changes the parameter representation by introducing a compact MAC CE format with specific bit fields for SpCell identification and activation status. This parameter encoding scheme reduces the signaling payload size compared to RRC messages while preserving all necessary configuration information, thereby reducing device complexity and signaling overhead without sacrificing configuration accuracy
3Loss of time
If lower layer signaling is used for inter-cell mobility, then signaling delays are reduced, but reliability of SpCell management may worsen
Solution Approach 1:
The patent applies preliminary action by pre-configuring SpCell parameters and MAC CE command structures during initial connection setup or RRC reconfiguration. This advance configuration ensures that when fast beam switching is needed, the MAC layer already has the necessary parameters ready, enabling rapid execution without compromising the reliability of SpCell management through pre-validated configurations
Solution Approach 2:
The patent incorporates feedback mechanisms where the network monitors the execution of MAC CE commands and can trigger RRC reconfiguration if anomalies are detected. This feedback loop ensures that the simplified MAC layer operations maintain reliability by falling back to more robust RRC management when needed, thus balancing speed and reliability in SpCell management
Data Source
AI summary
A method performed by a User Equipment (UE) is provided. The UE receives from a network node, a higher layer configuration comprising a set of SpCell configurations, to be configured in the UE. While being in connected state, the UE receives a lower layer signaling from a network node. The lower layer signaling comprises an indication. The indication indicates one or more SpCells comprised in the set of SpCell configurations, to be any one or more out of: activated or deactivated.