CSI Reporting for Dormant Secondary Cells in Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, dormant secondary cells continue to transmit control and reference signals even when no data is being sent, leading to inefficient resource usage and increased power consumption for both base stations and user equipment.
Innovation Solution
Implement a method to determine when a secondary carrier is dormant and adjust channel state information (CSI) reporting accordingly, suppressing periodic CSI reporting while continuing to report aperiodic CSI based on previous active periods, thereby reducing overhead signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If dormant secondary cells continue to transmit control and reference signals, then the UE can maintain channel quality information and quickly resume data transmission, but resource usage efficiency decreases and power consumption increases
Solution Approach 1:
The patent implements periodic CSI reporting only during active periods when data transmission is occurring, rather than continuous reporting during both active and dormant periods. This periodic approach allows the system to maintain necessary channel state information while significantly reducing the frequency of CSI transmissions, thereby lowering power consumption and resource usage during dormant periods while still enabling quick resumption of data transmission when needed.
2Loss of information
If periodic CSI reporting is continued during dormant periods, then channel state information remains updated, but signaling overhead increases
Solution Approach 1:
The patent extracts and removes periodic CSI reporting during dormant periods from the overall CSI reporting mechanism. By taking out this unnecessary reporting activity during periods when no data transmission occurs, the system eliminates the associated signaling overhead while maintaining sufficient channel state information through aperiodic reporting triggered by data transmission events, thus resolving the contradiction between information freshness and signaling quantity.
3Reliability
If aperiodic CSI reporting is maintained during dormant periods, then accurate channel measurements are available for quick resumption, but resource usage efficiency decreases
Solution Approach 1:
The patent implements a dynamic CSI reporting strategy where aperiodic reporting is triggered only by data transmission events rather than occurring continuously during dormant periods. This dynamic approach adjusts the reporting behavior based on actual system state - maintaining high reliability through aperiodic reporting when data transmission occurs, while improving resource efficiency by suppressing reporting during dormant periods when no data is being transmitted.
Data Source
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AI summary
Methods, systems, and devices are described for dynamic cell mode indication and reporting channel and interference feedback for dormant cells in a carrier aggregation environment. Indicators of cell mode for one or more secondary cells are sent using a transmission mechanism and may configure active or dormant sub-periods within the indicated periods. Indicators of cell mode for a secondary cell may be transmitted on a carrier of the primary cell, or the indicators may be transmitted on carriers of the secondary cell. Dormancy may also be indicated by the presence or absence of a cell mode indicator for predetermined time periods. When CSI measurements occur for a carrier of a dormant cell, the UE may report CSI for the dormant periods, suppress CSI reporting for the dormant periods, adjust a reporting frequency for the dormant periods, or report some types of CSI and not others for the dormant periods.