CSI Reporting in DRX Deactivated State
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Solution Overview
Problem
In next-generation mobile communication systems, there is a need to define a method for reporting measurement values of channel state reference signals in a deactivated state, as periodic reference signals are only reported during activation time in LTE, but partial periodic and one-time aperiodic signal transmissions are introduced, requiring a solution for continued reference signal transmission after activation time completion.
Innovation Solution
The solution involves reporting channel state reference signals and sounding reference signals in a deactivated state, allowing for timely completion of measurement reports and reducing the burden on terminals by preventing unnecessary measurements in specific serving cells, thereby reducing complexity and RF tuning delay time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If periodic reference signals are only reported during activation time in LTE, then terminal power consumption is reduced, but reference signal transmission continuity is insufficient for next-generation requirements
Solution Approach 1:
The patent applies dynamics by transitioning from static periodic reporting only during activation to dynamic reporting that adapts to DRX states. The terminal determines whether to report CSI based on whether it is in active time or deactivated state, and the network configures different reporting behaviors accordingly, making the system flexible and adaptive to different operational states.
Solution Approach 2:
The patent changes the reporting parameter behavior based on DRX state. When in deactivated state, the terminal may report only RI and CQI while omitting PMI, or report with reduced granularity. This parameter adjustment reduces uplink overhead and terminal processing burden while maintaining essential channel state information during low-activity periods.
2Adaptability or versatility
If partial periodic and one-time aperiodic signal transmissions are introduced, then reference signal transmission flexibility is improved, but reporting method complexity increases
Solution Approach 1:
The patent segments CSI reporting into different types based on signal transmission mode: periodic CSI reporting for regular updates, and aperiodic CSI reporting triggered by network requests. Each type has its own configuration and triggering mechanism, allowing the system to select appropriate reporting modes based on current needs without requiring complex handling of all modes simultaneously.
Solution Approach 2:
The patent creates a universal reporting framework that handles both periodic and aperiodic reference signals through a common DRX-state-aware mechanism. The same state determination logic (whether terminal is in active time) applies to both periodic and aperiodic reporting, simplifying the overall system design while maintaining flexibility for different signal types.
3Measurement precision
If reference signal transmission continues after activation time completion, then channel state information accuracy is improved, but terminal processing burden increases
Solution Approach 1:
The patent applies partial action by having the terminal report only essential CSI parameters (RI and CQI) during deactivated state, rather than full CSI including PMI. This partial reporting provides sufficient channel state information for basic scheduling decisions while significantly reducing terminal processing burden and uplink overhead compared to complete CSI reporting.
Data Source
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Figure 1d
AI summary
A method, terminal and base station are provided. The method includes receiving, from a base station, channel state information (CSI) configuration information associated with a transmission of an uplink signal, and discontinuous reception (DRX) configuration information. A DRX operation is performed based on the DRX configuration information. A control message for triggering the transmission of the uplink signal, during an active time according to the DRX operation, is received from the base station. It is determined whether a time resource for transmitting the uplink signal is in the active time based on the CSI configuration information. In response to the time resource not being in the active time, the uplink signal is transmitted according to a transmission type of the uplink signal based on the CSI configuration information.