SRS Power Control Across Multiple TRPs Using Path Loss Measurements
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Solution Overview
Problem
Existing wireless communications systems face challenges in configuring power control parameters for sounding reference signals (SRS) when a user equipment (UE) communicates with multiple transmission/reception points (TRPs), as channel conditions vary and clear methods for power control are lacking.
Innovation Solution
The UE receives multiple path loss reference signal (PL-RS) indices and corresponding power control parameters to calculate transmission power for SRS, using methods such as averaging, minimum/maximum values, or pseudo-random hopping based on time indices to ensure SRS reception at multiple TRPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE transmits SRS to multiple TRPs using conventional power control methods, then the transmission can be performed, but the channel conditions vary and clear power control methods are lacking leading to poor communication quality and interference
Solution Approach 1:
The patent segments the power control parameters into multiple path loss compensation values, each associated with specific reference signal indices. This allows the UE to measure and control power separately for different TRPs based on their individual channel conditions, resolving the complexity of unified power control while improving communication quality across multiple TRPs
Solution Approach 2:
The patent implements dynamic power control by enabling the UE to select different path loss compensation values based on measured channel conditions and reference signal quality. The UE dynamically adjusts transmission power for SRS to each TRP according to real-time path loss measurements, improving reliability while adapting to varying channel conditions
2Measurement precision
If the UE uses multiple path loss compensation values for different TRPs, then power control precision improves, but the complexity of measuring and selecting appropriate values increases
Solution Approach 1:
The patent performs preliminary measurement of reference signals and calculation of path loss values before actual SRS transmission. The UE measures downlink reference signals from each TRP, calculates path loss based on known reference power levels, and stores these pre-computed values for use during uplink power control, eliminating the need for real-time complex channel assessment during transmission
Solution Approach 2:
The patent establishes a feedback mechanism where the UE measures the quality of received reference signals and uses this information to select appropriate path loss compensation values. The UE feeds back channel condition information to the network, which adjusts power control parameters accordingly, improving measurement precision while managing complexity through iterative optimization
3Reliability
If the UE transmits SRS at higher power to ensure reception at all TRPs, then reception reliability improves, but interference with other SRS transmissions increases
Solution Approach 1:
The patent applies local quality control by adjusting SRS transmission power individually for each TRP based on its specific path loss conditions. Instead of using a uniform high power level that causes interference, the UE calculates optimal power levels for each TRP based on measured path loss, ensuring reliable reception at each TRP while minimizing overall interference with other SRS transmissions in the system
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive an indication of path loss compensation values corresponding to the reference signal indices. The UE may measure resources associated with the reference signal indices to generate path loss measurements. The UE may transmit a sounding reference signal using a transmission power based on the path loss measurements and the path loss compensation values.