Sidelink Pathloss Determination for Transmit Power Control
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in accurately determining downlink pathloss for sidelink communications, which affects transmit power control and leads to interference issues between device-to-device (D2D) communications and base station signals.
Innovation Solution
A method and apparatus for a user equipment (UE) to receive synchronization reference signals from a base station, measure the Reference Signal Received Power (RSRP) values, determine the highest RSRP value, and calculate downlink pathloss for sidelink open loop power control, enabling effective transmit power adjustment to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If downlink pathloss is determined for sidelink transmit power control, then transmit power optimization is improved, but interference between D2D and base station communications may worsen
Solution Approach 1:
The patent implements a feedback mechanism where the UE measures RSRP of synchronization reference signals from the base station, calculates downlink pathloss, and uses this information to adjust sidelink transmit power. The base station also provides reference signal power information to the UE, enabling closed-loop power control that optimizes transmit power while preventing excessive interference to base station communications.
Solution Approach 2:
The patent changes the parameter used for pathloss determination from traditional uplink-based methods to downlink-based RSRP measurements. By using the highest RSRP value from multiple synchronization reference signals and calculating downlink pathloss accordingly, the system adapts power control parameters to actual channel conditions, improving power optimization while managing interference through accurate pathloss estimation.
2Measurement precision
If multiple synchronization reference signals are measured to determine highest RSRP, then downlink pathloss determination accuracy is improved, but measurement complexity increases
Solution Approach 1:
The patent segments the pathloss determination process into distinct steps: measuring RSRP of multiple synchronization reference signals separately, identifying the highest RSRP value, and calculating downlink pathloss based on this highest value. This segmentation allows the UE to systematically process multiple measurements without overwhelming complexity, improving accuracy through multiple samples while maintaining manageable computational steps.
Solution Approach 2:
The patent performs preliminary RSRP measurements of multiple synchronization reference signals before final pathloss calculation. By pre-measuring and identifying the highest RSRP value in advance, the system prepares accurate pathloss input data beforehand, reducing the complexity of the final power control decision while improving overall determination accuracy through comprehensive prior measurement.
Data Source
AI summary
In an aspect, the present disclosure includes a method, apparatus, and computer readable medium for wireless communications for receiving, by a user equipment (UE) from a base station, a plurality of synchronization reference signals; measuring, by the UE, a respective Reference Signal Received Power (RSRP) value of each of the plurality synchronization reference signals; determining, by the UE, a highest RSRP value from each of the respective RSRP values; and calculating, by the UE, a downlink pathloss associated with a sidelink open loop power control based on the highest RSRP value.