Uplink Transmission Power Control Using Pathloss Reference Signals
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Solution Overview
Problem
In 5G New Radio (NR) systems, determining optimal uplink transmission power for PUCCH and SRS transmissions is challenging due to the lack of effective methods for accurately estimating pathloss and interference, leading to potential interference with other cells and suboptimal SINR values.
Innovation Solution
The method involves configuring power control parameters for SRS and PUCCH resources, including pathloss reference signals, to determine transmit power, with default spatial relation information applied when specific configurations are absent, using CSI-RS or SS/PBCH blocks for pathloss estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uplink transmit power is increased to improve SINR at the receiver side, then signal quality is improved, but interference to other cells increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the uplink transmit power based on calculated pathloss values and power control parameters. The transmit power is computed as P=min{PCMAX, {P0+α×PL+g+10 log10M+Δ}} where PL represents pathloss estimated from downlink reference signals. This allows the system to optimize power levels to achieve target SINR while controlling interference to other cells through precise power management.
2Measurement precision
If pathloss estimation accuracy is improved, then uplink power control precision is improved, but measurement and calculation complexity increases
Solution Approach 1:
The patent uses downlink reference signals (such as CSI-RS or SS/PBCH blocks) as intermediaries to estimate uplink pathloss. Instead of directly measuring uplink pathloss which would be complex, the system measures downlink reference signal received power (RSRP) and uses the relationship between transmit and received power to derive the pathloss value. This intermediary approach simplifies the measurement process while maintaining accuracy.
Solution Approach 2:
The patent implements feedback mechanisms where the UE continuously monitors downlink reference signals and updates pathloss estimates based on measured RSRP values. The power control parameter g represents closed-loop power control adjustments based on feedback from the network. This feedback approach enables continuous optimization of power estimation accuracy while managing complexity through standardized measurement procedures.
3Manufacturing precision
If power control parameters are precisely configured, then transmission power determination accuracy is improved, but system configuration complexity increases
Solution Approach 1:
The patent applies local quality by assigning specific power control parameters (P0, α, g, M, Δ) to different transmission scenarios and conditions. Each parameter is optimized for specific use cases such as different bandwidth configurations, modulation schemes, and power control modes. The RRC configuration allows selective activation of pathloss reference signals and power control parameters tailored to local network conditions, achieving precise power determination without requiring all parameters to be configured everywhere.
Data Source
AI summary
A method, a User Equipment, a computer program and a computer readable medium for determining a transmission power of an uplink transmission. The method includes: determining, by a User Equipment (UE), a Reference Signal (RS) resource index providing a periodic RS resource; calculating, by the UE, a downlink pathloss estimate using the RS resource index; determining, by the UE, the transmission power of the uplink transmission based on the downlink pathloss estimate.