Terminal Apparatus CQI Update for LBT Subbands
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Solution Overview
Problem
Current radio communication systems, particularly in the context of New Radio (NR) and LTE, face challenges in efficiently managing channel state information-reference signals (CSI-RS) and channel quality indicators (CQI) in unlicensed frequency bands, leading to suboptimal communication performance due to Listen Before Talk (LBT) subbands failures.
Innovation Solution
A terminal apparatus and method that measure and evaluate CSI-RS to update CQI values, transmitting CSI reports only when specific conditions related to unlicensed carriers and LBT subbands are met, ensuring efficient communication by differentiating between successful and unsuccessful LBT subbands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CSI-RS is measured and CQI is updated for all subbands in unlicensed carriers, then communication reliability is improved, but device complexity and processing overhead increase due to LBT failure handling
Solution Approach 1:
The patent extracts and separates the handling of successful and unsuccessful LBT subbands. For unsuccessful LBT subbands, the CQI update process is skipped entirely, while only successful subbands undergo full CQI measurement and update. This extraction simplifies processing by removing unnecessary operations from failed subbands while maintaining reliability through selective updates.
Solution Approach 2:
The patent applies different quality treatment to different subbands based on their LBT outcomes. Successful LBT subbands receive full CQI measurement and update (high quality treatment), while unsuccessful subbands receive no update (low quality treatment). This local differentiation optimizes processing resources and reduces overall complexity while maintaining communication reliability where needed.
2Measurement precision
If CQI is updated for all subbands including unsuccessful LBT subbands, then measurement precision is improved, but loss of time increases due to unnecessary updates on failed subbands
Solution Approach 1:
The patent extracts the CQI update operation from unsuccessful LBT subbands, recognizing that these subbands cannot provide meaningful CQI measurements. By removing the time-consuming update process from failed subbands, the system reduces overall processing time while maintaining measurement precision for successful subbands where actual channel quality data exists.
Solution Approach 2:
The patent applies partial action by updating CQI only for successful LBT subbands rather than all subbands. This partial approach avoids excessive processing time on failed subbands where no valid measurement data exists, while still achieving sufficient measurement precision for the subset of functional subbands.
3Device complexity
If wideband CQI is reported without considering LBT status, then device complexity is reduced, but communication efficiency deteriorates due to unnecessary reports from failed subbands
Solution Approach 1:
The patent incorporates LBT status feedback into the CQI reporting decision process. The terminal apparatus uses feedback information about whether LBT was successful in each subband to determine whether to include that subband's CQI in the wideband report. This feedback mechanism maintains communication efficiency by excluding failed subbands from reports while preserving simplicity through a unified reporting structure.
Data Source
AI summary
A terminal apparatus and a method are provided. The terminal apparatus includes a receiver configured to receive at least a channel state information-reference signal (CSI-RS) in a bandwidth part (BWP), a measurer configured to measure and evaluate one or more values of a channel quality indicator (CQI) by using at least the CSI-RS, the CQI including a wideband CQI or a subband CQI, and to measure and update a value of the wideband CQI in a case that an indicator, corresponding to the BWP, indicates the wideband CQI, and at least one of a first condition and a second condition is not satisfied, and a transmitter configured to transmit a CSI report including the value of the wideband CQI.