MAC-CE Uplink Power Control for High-Mobility NR
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Solution Overview
Problem
In high mobility scenarios of NR wireless communications, frequent RRC messaging for power control updates consumes significant communication resources, affecting latency and reliability due to large transmission payloads.
Innovation Solution
Implementing power control configuration via MAC-CE messaging, which includes a smaller payload than RRC messages, allowing the UE to update path loss reference signals and adjust power based on received MAC-CE messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent RRC messaging is used for power control updates in high mobility scenarios, then power control accuracy is improved, but signaling overhead increases and communication resources are consumed
Solution Approach 1:
The power control configuration is segmented into two parts: (1) RRC messaging that configures multiple power control configuration indexes and their associated parameters, and (2) MAC-CE messaging that selectively activates specific configuration indexes. This segmentation allows the system to pre-configure multiple power control options via RRC but only transmit activation indicators via MAC-CE, thereby reducing frequent RRC messaging overhead while maintaining power control accuracy in high mobility scenarios
Solution Approach 2:
The system performs preliminary configuration by pre-defining multiple power control configuration indexes with their associated parameters through RRC messaging before high mobility scenarios occur. When the UE enters high mobility mode, it can quickly switch between pre-configured indexes using MAC-CE activation without requiring full RRC reconfiguration, thus maintaining responsiveness while reducing signaling overhead
2Reliability
If frequent RRC messaging is used for power control updates, then power control reliability is improved, but transmission latency increases due to large payload sizes
Solution Approach 1:
The invention extracts only the essential activation indicator from the full power control configuration and transmits it via MAC-CE messaging, while the detailed configuration parameters remain pre-configured in the UE. This extraction approach maintains power control reliability by ensuring accurate configuration is always available in the UE, while dramatically reducing transmission latency by sending only brief activation indicators rather than complete configuration payloads
3Quantity of substance
If MAC-CE messaging is used for power control updates, then signaling overhead is reduced, but configuration flexibility may be limited
Solution Approach 1:
The system implements dynamic configuration where the UE is pre-configured with multiple power control configuration indexes through RRC messaging, each representing different power control parameters suitable for various mobility scenarios. The MAC-CE messaging dynamically activates the appropriate index based on current conditions, providing both the reduced overhead of MAC-CE and the flexibility of multiple pre-configured options adaptable to different scenarios
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. Techniques described herein may provide power control configuration parameters using MAC-CE messaging. A base station may transmit a MAC-CE message that includes a power control configuration identifier. The UE may identify a power control configuration according to the power control configuration identifier. The power control configuration may include one or more power control parameters and a path loss reference signal identifier. The UE may update the path loss reference signal for an uplink transmission based on the received MAC-CE message and adjust power for performance of the uplink transmission according to one or more measurements of the updated path loss reference signal.