Multi-TRP C-JT SRS Power Control With Joint Pathloss
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Solution Overview
Problem
Current 3GPP NR standards for uplink channel sounding in multi-TRP scenarios face inefficiencies due to sequential channel sounding across multiple TRPs, leading to increased overhead and near-far problems, as they do not account for multiple pathloss reference points from different TRPs, necessitating separate SRS resource sets for each TRP.
Innovation Solution
A new UL transmit power control procedure that uses a single SRS resource set to simultaneously sound channels for multiple TRPs, based on a joint metric of pathloss reference points, reducing overhead and ensuring accurate channel estimation by implicitly incorporating relative pathloss differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate SRS resource sets are used for each TRP to account for multiple pathloss reference points, then channel estimation accuracy is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent combines multiple SRS resource sets into a single unified SRS resource set that serves multiple TRPs simultaneously. This is achieved by introducing a new SRS resource set type with uplinkPowerControl that references multiple pathlossReferenceRS resources, allowing the UE to calculate a single transmit power level that accounts for pathloss to multiple TRPs, thereby reducing signaling overhead while maintaining channel estimation accuracy.
Solution Approach 2:
The patent creates a universal SRS resource set configuration that can be used for multiple TRPs with different pathloss characteristics. The uplinkPowerControl structure is enhanced to support multiple pathlossReferenceRS resources, making the same SRS resource set applicable across different TRPs without requiring separate configurations, thus reducing system complexity.
2Reliability
If separate SRS resource sets are configured for each TRP, then pathloss-specific power control is achieved, but overhead increases
Solution Approach 1:
The patent merges multiple pathloss reference points into a single uplinkPowerControl configuration that references multiple pathlossReferenceRS resources. The UE calculates transmit power based on a combination of these reference points, achieving accurate power control for multiple TRPs through a single SRS resource set configuration, thereby reducing signaling overhead while maintaining power control accuracy.
3Measurement precision
If sequential channel sounding is performed across multiple TRPs, then each TRP receives dedicated channel information, but time consumption and overhead increase
Solution Approach 1:
The patent enables simultaneous channel sounding for multiple TRPs by using a single SRS resource set with unified power control. The UE transmits SRS once, and the network uses the multiple pathlossReferenceRS configurations to derive channel information for multiple TRPs concurrently, eliminating the need for sequential sounding and reducing time consumption.
Data Source
AI summary
There is provided a method, computer program and apparatus for causing apparatus at least to: receive a sounding reference signal configuration comprising one or more sounding reference signal resources and/or resource sets for sounding reference signal resource transmission; obtain multiple pathloss reference points from the one or more reference signal resources, the one or more reference signal resources associated with multiple transmission configuration indicator states, the multiple transmission configuration indicator states associated with multiple transmission and reception points having the same or different physical cell identifiers; determine a transmit power level for the sounding reference signal resource transmission to sound a channel for the multiple transmission and reception points, based on a joint metric of the multiple pathloss reference points; determine a set of transmission and reception points of the multiple transmission and reception points, based on the determined transmit power level; and transmit uplink data or a reference signal or control information based on the determined transmit power level from a user equipment to the multiple transmission and reception points within the set, using the one or more sounding reference signal resources.