CSI Location Label for Flexible Aperiodic Feedback in LTE
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Solution Overview
Problem
In LTE and LTE-A systems, the existing methods for transmitting aperiodic channel state information (CSI) across multiple cells and carriers lead to inefficient use of uplink resources and complexity in scheduling grant command design, particularly when the number of cells and carriers increases, due to the need for concurrent feedback or increased CSI request field lengths.
Innovation Solution
A method where CSI is sent or received without altering the length of the aperiodic CSI request field by using a CSI location label obtained from the scheduling grant command, allowing flexible triggering of CSI for part or all cells and carriers between user equipment and base station, simplifying the design of the scheduling grant command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the length of the aperiodic CSI request field is increased to support multiple cells and carriers, then the capability to trigger CSI feedback for multiple cells/carriers is improved, but the reliability of the scheduling grant command deteriorates and the device complexity increases
Solution Approach 1:
The patent segments the CSI feedback triggering mechanism by introducing a CSI location label that identifies specific carriers or cells. Instead of using a single long CSI request field to trigger all CSI feedback, the system divides the feedback into multiple parts, each associated with a specific CSI location label. This allows the original short CSI request field to remain unchanged and reliable, while still supporting multiple cells and carriers through the segmented labeling approach.
Solution Approach 2:
The patent introduces a CSI location label as an intermediary element between the scheduling grant command and the CSI feedback. This intermediary carries the identification information of the target carrier or cell, allowing the base station to specify which CSI feedback is requested without expanding the original CSI request field. The CSI location label acts as a mediator that enables precise targeting of CSI feedback for multiple cells and carriers while keeping the scheduling grant command structure intact.
2Loss of information
If concurrent sending or receiving of aperiodic CSI feedback for all cells or downlink component carriers is implemented, then the completeness of CSI feedback is improved, but the uplink resource consumption increases
Solution Approach 1:
The patent implements partial action by allowing the base station to selectively request CSI feedback for specific cells or carriers using the CSI location label, rather than requiring concurrent feedback for all cells and carriers. The user equipment only transmits CSI feedback for the indicated cells/carriers, reducing uplink resource consumption while still providing the necessary CSI information for the base station's scheduling decisions. This selective feedback approach avoids the waste of transmitting unnecessary CSI data.
Solution Approach 2:
The patent introduces dynamic flexibility in CSI feedback transmission by enabling the base station to adaptively select which cells or carriers require CSI feedback based on current channel conditions and scheduling needs. The CSI location label dynamically identifies the target cells/carriers, allowing the system to adjust the scope of CSI feedback from single-cell to multi-cell scenarios as needed, optimizing uplink resource usage while maintaining feedback completeness for the required cells.
Data Source
AI summary
A method, a user equipment, and a base station for transmitting channel state information (CSI) are disclosed. First, a scheduling grant command is sent by a base station. A CSI location label is obtained according to information of a resource occupied by the scheduling grant command and information of a resource occupied by a data channel that is indicated by the scheduling grant command. CSI of a carrier corresponding to the CSI location label is sent to the base station through the data channel. The CSI location label may be obtained through the scheduling grant command and the CSI of the carrier corresponding to the CSI location label may be sent or received without changing a length of an aperiodic CSI request field.