CJT Doppler Offset Reporting for Fresher CSI With Lower Overhead
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Solution Overview
Problem
Existing CJT communication systems face issues with outdated channel state information (CSI) due to interference, leading to degraded performance, and conventional solutions like increased CSI reporting frequency do not adequately address this problem.
Innovation Solution
Implementing Doppler offset reporting in CJT communications by estimating and adjusting downlink transmissions based on Doppler spectrum and offset indications between cooperative TRPs and a serving TRP, reducing CSI-RS overhead and computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSI reporting frequency is increased to address outdated channel state information, then channel state information freshness is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent extracts only the essential Doppler offset parameter from the full CSI report, allowing the network to track channel changes without requiring complete CSI retransmission. This selective extraction maintains channel state information freshness while significantly reducing signaling overhead compared to increasing full CSI reporting frequency.
Solution Approach 2:
The patent changes the reporting parameter from comprehensive CSI to a specific Doppler offset parameter that characterizes channel dynamics. This parameter transformation enables the network to infer channel state evolution with minimal reporting, resolving the contradiction between information freshness and overhead reduction.
2Measurement precision
If Doppler spectrum estimation is performed for each cooperative TRP, then channel state information accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent segments the Doppler spectrum estimation process to focus only on the Doppler offset parameter rather than computing the complete Doppler spectrum for each cooperative TRP. This segmentation maintains the essential accuracy needed for channel tracking while significantly reducing computational complexity by eliminating redundant calculations.
Solution Approach 2:
The patent applies partial action by computing only the necessary Doppler offset indication rather than the full Doppler spectrum characterization. This partial computation provides sufficient accuracy for coherent joint transmission while avoiding the excessive computational burden of complete spectrum analysis for each TRP.
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 significantly alleviates outdated CSI issues, improving system performance and reducing overhead and computational complexity in CJT communications.
Implementation Method 1
estimating a Doppler spectrum for each cooperative TRP of the one or more cooperative TRPs, wherein the Doppler spectrum is estimated using a downlink reference signal of the each cooperative TRP relative to the downlink reference signal of the serving TRP
Data Source
AI summary
This disclosure provides systems, methods, and devices for wireless communication that support Doppler offset reporting for coherent joint-transmission (CJT) communications. In a first aspect, a method of wireless communication includes measurement by a user equipment (UE) of a Doppler offset indication for each cooperative transmission-reception point (TRP) of multiple TRPs in CJT communications with the UE. The UE would report the Doppler offset indication to the serving TRP, which forwards the Doppler offset indication to each corresponding cooperative TRP. Each cooperative TRP may then use the Doppler offset indication to adjust downlink CJT communications with the UE. Other aspects and features are also claimed and described.