Downlink TRS Configuration with Coherent CSI-RS Resources
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Solution Overview
Problem
Existing techniques 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 and synchronization due to incoherency in radio chains and precoder changes.
Innovation Solution
A network node configures a reference signal resource set with parameters indicating coherent transmission, allowing wireless devices to determine whether frequency synchronization can be performed using the same antenna port, radio frequency, and precoder across resources, and report channel state information accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple CSI-RS resources are used for TRS configuration, then frequency estimation accuracy improves, but incoherency in radio chains and precoder changes degrades synchronization performance
Solution Approach 1:
The patent introduces a coherence indicator parameter that changes the state of CSI-RS resources from incoherent to coherent by ensuring consistent transmission parameters (precoder, radio chain, antenna port) across multiple resources, thereby resolving the contradiction between using multiple resources for accuracy while maintaining reliability
Solution Approach 2:
Instead of allowing incoherent transmission and trying to correct it, the patent inverts the approach by mandating coherent transmission through the coherence indicator, which requires all CSI-RS resources to use the same antenna port, precoder, and radio chain, thus eliminating the incoherency problem at its source
2Measurement precision
If coherent transmission is enforced across all CSI-RS resources, then frequency synchronization accuracy improves, but device complexity increases due to additional configuration parameters
Solution Approach 1:
The patent applies partial action by introducing the coherence indicator only where needed - when frequency synchronization is required. The indicator is optional and only activates additional coherence requirements when present, avoiding unnecessary complexity in scenarios where coherent transmission is not needed
Solution Approach 2:
The coherence indicator parameter serves as a switch that changes the operational mode: when absent or set to false, normal independent CSI-RS configuration is allowed; when set to true, it enforces coherent transmission parameters, thus managing complexity through parameter-based configuration changes
3Reliability
If the same antenna port is used across all TRS resources, then frequency estimation reliability improves, but adaptability decreases when different antenna ports are needed for different purposes
Solution Approach 1:
The coherence indicator parameter dynamically changes the antenna port configuration state: when coherence is required, the same antenna port is enforced across all resources; when coherence is not required, different antenna ports can be used, thus providing adaptability through parameter-based state changes
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.