Downlink TRS Configuration for Coherent CSI-RS Frequency Tracking
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Solution Overview
Problem
Existing methods for configuring downlink tracking reference signals (TRS) in New Radio (NR) face challenges in ensuring coherent signal generation across multiple CSI-RS resources, leading to inaccurate frequency estimation due to incoherency in radio chains or precoder changes, which affects synchronization and channel state information reporting.
Innovation Solution
A network node configures a reference signal resource set with parameters indicating coherent transmission, allowing wireless devices to determine if frequency synchronization can be performed using the same antenna port, radio frequency, and precoder across resources, and to report channel state information accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple CSI-RS resources are configured for TRS without coherence indication, then resource flexibility is improved, but frequency estimation accuracy deteriorates due to incoherency in radio chains or precoder changes
Solution Approach 1:
The network node provides feedback to the wireless device through a configuration parameter that explicitly indicates whether coherent signal generation is used across multiple CSI-RS resources. This feedback mechanism allows the wireless device to correctly interpret the coherence status and perform appropriate frequency estimation, resolving the accuracy issue while maintaining resource flexibility.
Solution Approach 2:
A new configuration parameter is introduced to change the state information conveyed to the wireless device. This parameter explicitly indicates whether coherent signal generation is used across multiple CSI-RS resources, allowing the system to adapt the frequency estimation process based on the actual coherence status without sacrificing resource configuration flexibility.
2Measurement precision
If coherent signal generation is assumed across multiple CSI-RS resources, then frequency estimation accuracy is improved, but device complexity increases due to additional coherence verification
Solution Approach 1:
The network node self-announces its signal generation coherence status through the configuration parameter. The wireless device does not need to perform complex verification procedures; instead, it simply uses the indicated coherence status to guide its frequency estimation process, reducing device complexity while maintaining accuracy.
Solution Approach 2:
The coherence status is determined and indicated by the network node in advance through the configuration parameter, before the wireless device performs frequency estimation. This preliminary action eliminates the need for complex real-time verification at the device side, reducing complexity while ensuring accurate frequency estimation.
3Manufacturing precision
If TRS configuration uses separate parameters for each resource, then configuration precision is improved, but signaling overhead increases
Solution Approach 1:
The coherence status, which applies to multiple CSI-RS resources collectively, is merged into a single configuration parameter. This single parameter conveys the coherence status for all resources simultaneously, reducing signaling overhead while maintaining the precision needed for frequency estimation across the resource set.
Data Source
AI summary
A method, wireless device and network node are disclosed. According to one aspect, a method for a wireless device includes receiving a configuration of a reference signal resource set from the network node, the reference signal resource set being a set of single-symbol and single antenna port reference signal resources in at least one slot; and based on at least one parameter of the received configuration, determining whether the UE can assume a same antenna port for all reference signal resources of the reference signal resource set.