Terminal CQI Feedback Adaptation for FD-MIMO Transmission Modes
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Solution Overview
Problem
In the context of FD-MIMO technology, there is a challenge in matching the CQIs reported by the TDD system with the actual downlink transmission mode, leading to inefficiencies in downlink transmission performance and increased overhead in current LTE/LTE-A systems.
Innovation Solution
A method where a terminal determines the number of CQIs to be fed back based on the number of CSI-RS ports, downlink DMRS ports, and configuration signaling from the base station, ensuring alignment with the actual downlink transmission needs, thereby improving transmission reliability and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the terminal reports CQIs based on transmission diversity assumption in TDD FD-MIMO systems, then the CQI feedback overhead is reduced, but the matching between reported CQIs and actual downlink transmission mode deteriorates
Solution Approach 1:
The patent applies dynamics by making the CQI reporting behavior adaptive rather than static. The terminal dynamically adjusts whether to report transmission diversity CQI or spatial multiplexing CQI based on real-time detection of downlink transmission modes. This dynamic adaptation resolves the contradiction by allowing the system to reduce overhead when appropriate while ensuring accurate matching when spatial multiplexing is detected.
Solution Approach 2:
The patent implements a feedback mechanism where the terminal detects the downlink transmission mode and uses this information to adjust its CQI reporting strategy. The feedback loop involves monitoring the downlink transmission mode and adjusting the CQI reporting behavior accordingly, ensuring that the reported CQIs match the actual transmission mode while managing feedback overhead efficiently.
2Reliability
If the terminal detects downlink transmission mode and adjusts CQI reporting accordingly, then the matching accuracy improves, but the detection and processing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the CQI reporting process into distinct segments based on transmission mode detection. The terminal segments its reporting behavior into different modes: reporting transmission diversity CQI when detection indicates diversity mode, and reporting spatial multiplexing CQI when detection indicates spatial multiplexing mode. This segmentation simplifies the overall complexity by creating clear, manageable decision paths.
Solution Approach 2:
The patent changes the parameter of CQI reporting behavior based on the detected transmission mode parameter. When the downlink transmission mode parameter changes, the terminal adjusts its CQI reporting parameter accordingly. This parameter-based approach manages complexity by using standardized parameter changes rather than complex processing logic.
Data Source
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AI summary
Provided are a method and apparatus for determining the quantity of channel quality indicators (CQI). The method comprises: a terminal determining the quantity of layers or the quantity of CQIs to be fed back according to at least one piece of the following pieces of information: the quantity of ports of a channel state information referenced signal (CSI-RS), the quantity of ports of a downlink demodulation reference signal (DMRS), and a configuration signalling of a base station. The present invention solves the problem of non-matching between CQIs reported by a TDD system under an FD-MIMO and CQIs actually needing to be used in the related art, improves the reliability of downlink transmission, saves overheads of a downlink signalling, and improves the downlink transmission performance.