UE CSI Reporting for Scell Activation Timing
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Solution Overview
Problem
In LTE-Advanced systems, mobile stations face processing delays when transitioning a secondary cell (Scell) from a deactive to an active state, leading to uncertainties for the radio base station in recognizing the completion of this transition, which affects proper rate matching and CSI reporting.
Innovation Solution
The mobile station initiates CSI reporting at a predetermined timing before the Scell's transition to the active state is completed, allowing the radio base station to recognize the transition's completion based on valid CSI receipt, and manages the Scell's deactivation timer to synchronize with the base station's timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile station transitions the Scell from deactive to active state, then communications can be performed in the Scell, but processing delay occurs due to RF retuning and other operations
Solution Approach 1:
The mobile station performs preliminary actions during the processing delay period by starting CSI reporting before the Scell transition is complete. The control unit determines that the transition is not completed until valid CSI is received by the base station, allowing the system to prepare in advance while maintaining reliable communication once the transition finishes.
2Loss of information
If the mobile station starts CSI reporting before Scell transition is completed, then the base station can recognize transition completion timing, but invalid CSI may be reported during the transition period
Solution Approach 1:
The system dynamically adjusts the interpretation of CSI reports based on the transition state. During the transition period, the base station understands that CSI may be invalid and uses the receipt of valid CSI as the dynamic marker for transition completion. The control unit flexibly determines completion timing based on whether CSI is valid, allowing accurate recognition without compromising measurement precision requirements.
3Manufacturing precision
If the base station waits for Scell transition completion before scheduling, then proper rate matching can be performed, but scheduling efficiency is reduced
Solution Approach 1:
The base station uses feedback from CSI reporting to determine when the Scell transition is complete. By monitoring the receipt of valid CSI from the mobile station, the base station can accurately determine transition completion timing and begin scheduling accordingly, maintaining proper rate matching while improving scheduling efficiency through timely resource allocation.
Data Source
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Figure 3
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AI summary
An objective is to enable a radio base station eNB to recognize a time point when a transition of an Scell to an active state is completed. A mobile station UE according to the invention includes a transmission unit 14 configured to, when an activation command for a deactive Scell is received, start reporting of CSI in the Scell to the radio base station eNB at predetermined timing before transition of an Scell to an active state is completed. The transmission unit 14 reports CSI to the radio base station eNB at predetermined intervals even during a time period from the time point when the CSI reporting is started to a time point when the transition of the Scell to the active state is completed.