Path-loss Reference Signal Activation for Uplink Power Control
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Solution Overview
Problem
In wireless communications, existing systems face challenges in accurately estimating path-loss for uplink transmissions, especially in scenarios with frequent channel changes due to beamforming techniques, where tracking path-loss estimates for all possible beam pairs is impractical due to channel overhead and processing capacity limitations.
Innovation Solution
The method involves activating and deactivating specific path-loss reference signals for estimation, using MAC-CE messages to update these signals, and performing layer 3 filtering on measured path-loss values to determine accurate estimates, allowing for efficient uplink transmit power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If path-loss reference signals are activated and deactivated dynamically, then path-loss estimation accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent extracts only the necessary reference signals for path-loss estimation from the complete set of configured reference signals. By identifying and activating only those reference signals that are currently needed for accurate path-loss measurement, the system avoids processing unnecessary signals, thereby reducing signaling overhead while maintaining estimation accuracy.
Solution Approach 2:
The patent implements dynamic activation and deactivation of reference signals based on current channel conditions and beamforming configurations. This dynamic approach allows the system to adaptively adjust which reference signals are active, ensuring accurate path-loss estimation follows channel changes while minimizing the number of active signals to reduce overhead.
2Measurement precision
If all beam pair path-loss estimates are tracked, then path-loss estimation accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent extracts and processes only the path-loss estimates for currently active beam pairs rather than maintaining estimates for all possible beam pairs. This selective approach reduces the processing burden while ensuring that path-loss information is available for all active transmissions.
Solution Approach 2:
The patent applies different processing quality levels to different beam pairs based on their current activity status. Active beam pairs receive full path-loss estimation processing, while inactive beam pairs do not require continuous estimation. This local differentiation reduces overall processing complexity while maintaining accuracy where needed.
3Adaptability or versatility
If reference signals are updated frequently, then adaptability to channel changes is improved, but latency increases
Solution Approach 1:
The patent performs preliminary path-loss estimation using already-received reference signals before channel changes occur. By having path-loss estimates ready in advance based on previously received reference signals, the system can quickly adapt to channel changes without waiting for new reference signal transmissions, thereby reducing latency while maintaining adaptability.
Solution Approach 2:
The patent implements dynamic reference signal activation that responds to channel changes only when necessary. Rather than updating reference signals at fixed high frequency, the system monitors channel conditions and activates updated reference signals only when actual channel changes are detected, reducing unnecessary updates and associated latency.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. In some systems, a user equipment (UE) may perform path-loss estimation to support uplink transmit power control. The UE may perform path-loss estimations on path-loss reference signals configured by a base station. In some cases, the base station may update (e.g., activate, deactivate, or both) particular path-loss reference signals using a medium access control (MAC) control element (CE). The UE may determine which path-loss reference signal or signals to use for path-loss estimation based on one or more techniques. For example, the UE may filter path-loss measurements over a time duration or may use a single, unfiltered path-loss measurement for path-loss estimation. Additionally or alternatively, the UE may receive deactivated path-loss reference signals (e.g., for a set amount of time or for any amount of time) or may refrain from receiving deactivated path-loss reference signals.