Sounding Reference Signal Configuration for Multi-TRP Doppler Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-speed user equipment (UE) in wireless communication systems, such as those on high-speed trains, experience severe Doppler shifts and inter-carrier interference due to rapid geographic location changes, leading to inaccurate channel measurements and increased pathloss, which can result in radio link failures.
Innovation Solution
Implementing a method where the UE receives downlink and uplink reference signals from multiple transmission/reception points (TRPs) to calculate combined frequency offsets and perform optimized Doppler parameter estimation, and configuring SRS resource sets for non-codebook based transmission to manage beamforming and precoding across multiple TRPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE travels at high speed in HST scenarios, then communication coverage is provided, but severe Doppler shifts and inter-carrier interference occur leading to inaccurate channel measurements
Solution Approach 1:
The system performs preliminary Doppler parameter estimation and frequency offset calculation using reference signals (SSB, CSI-RS, or SRS) before actual data transmission. This preliminary action allows the UE and network to compensate for Doppler effects in advance, improving channel measurement accuracy despite high-speed movement.
Solution Approach 2:
The patent replaces traditional single-TRP channel estimation with a multi-TRP collaborative estimation system. By combining channel measurements from multiple transmission/reception points, the system achieves more accurate channel state information that can withstand high-speed Doppler effects, substituting the mechanical limitation of single-point measurement with a distributed measurement approach.
2Reliability
If wider bandwidth is used for communication in mmW spectrum, then line-of-sight communication is improved, but pathloss increases rapidly leading to radio link failure
Solution Approach 1:
The patent combines signals from multiple TRPs using techniques such as non-coherent combining or coherent combining with phase compensation. This merging of multiple signal paths provides diversity gain that compensates for the rapid pathloss in mmW bands, maintaining reliable communication even when individual links experience high attenuation.
Solution Approach 2:
The system introduces multiple TRPs as intermediary transmission points between the UE and the core network. These intermediaries provide multiple relay paths, allowing the signal to reach the UE through alternative routes that experience lower pathloss, thereby maintaining connection reliability in high-frequency mmW communication.
3Loss of time
If multiple TRPs are used for simultaneous communication, then latency is reduced for URLLC, but device complexity increases for managing SRS resource sets and beamforming
Solution Approach 1:
The patent segments the SRS resource configuration into separate, independently configurable SRS resource sets, each associated with specific TRPs. This segmentation allows the UE to manage uplink sounding for multiple TRPs through distinct resource sets with different parameters (time, frequency, spatial filters), reducing the complexity of managing unified multi-TRP resources while enabling parallel operations.
Solution Approach 2:
The system implements dynamic SRS resource set configuration where the network can activate, deactivate, or reconfigure specific SRS resource sets based on current communication conditions, TRP availability, and service requirements. This dynamic management allows the system to adapt the complexity level to actual needs, using full multi-TRP capability only when necessary for URLLC while simpler configurations can be used otherwise.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces latency and increases reliability for ultra-reliable low-latency communication (URLLC) by mitigating Doppler effects and pathloss, enabling stable communication even in high-speed scenarios.
Implementation Method 1
the rate at which the UE may be moving may introduce some characteristics to the channels on which the UE communicates that would otherwise be absent (or less severe) in non-HST scenarios. For example, high Doppler shifts
Data Source
AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE or a component thereof. The apparatus may be configured to receive a first downlink reference signal associated with a first TRP. The apparatus may be further configured to receive a second downlink reference signal associated with a second TRP. The apparatus may be further configured to transmit, to the first TRP and the second TRP, at least one sounding reference signal that is associated with both the first downlink reference signal and the second downlink reference signal.