CSI-RS Channel Quality Reporting in Non-PMI LTE Transmission
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Solution Overview
Problem
Current LTE systems lack a CSI-RS based measurement and reporting method for channel quality information in non-PMI feedback-based transmission modes, particularly in TM 9, which restricts the ability to generate CQI/PMI/RI reporting information.
Innovation Solution
A method and device for UE to measure CSI-RS, determine, and report CQI using a downlink channel transport matrix acquired from CSI-RS measurements, allowing CSI-RS based channel quality information reporting in non-PMI feedback transmissions, with specific transmission schemes for PDSCH based on the number of CSI-RS ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the LTE system adopts various adaptive technologies and multiple transmission modes to adapt to different transmission environments, then the system adaptability and transmission efficiency are improved, but the device complexity and control overhead increase
Solution Approach 1:
The patent segments the channel quality reporting into multiple independent components: wideband CQI for overall channel quality and subband CQI for frequency-selective information. This segmentation allows the system to adapt to different transmission conditions by selectively reporting only necessary components, improving adaptability while controlling complexity through modular reporting structure
Solution Approach 2:
The patent implements dynamic adjustment of CQI reporting parameters based on channel conditions. The UE dynamically determines whether to report wideband or subband CQI, adjusts reporting periodicity based on channel variability, and selectively reports only when channel conditions change significantly. This dynamic behavior enables the system to adapt to varying transmission environments while reducing unnecessary reporting overhead
2Measurement precision
If the UE reports detailed channel quality information including subband CQI for frequency selective scheduling, then the scheduling accuracy and frequency selective gain are improved, but the feedback overhead and signaling complexity increase
Solution Approach 1:
The patent applies local quality by reporting different levels of CQI detail for different frequency regions. Instead of uniformly reporting high-precision subband CQI across all bands, the UE reports wideband CQI for stable channels and subband CQI only for frequency regions with significant selective fading. This localized precision approach maintains scheduling accuracy where needed while reducing feedback overhead in stable regions
Solution Approach 2:
The patent implements partial reporting by selectively transmitting only the necessary portion of channel quality information. The UE determines whether to report wideband or subband CQI based on channel conditions, and may skip reporting in certain subframes when channel conditions are stable. This partial action approach provides sufficient scheduling information without the excessive overhead of always reporting complete subband details
3Productivity
If the system supports dynamic adjustment of MIMO transmission parameters including rank and precoding, then the transmission efficiency and spectral utilization are improved, but the control complexity and feedback requirements increase
Solution Approach 1:
The patent implements structured feedback mechanisms where the UE reports CQI, PMI (Precoding Matrix Indicator), and RI (Rank Indicator) based on channel measurements. The feedback is organized hierarchically with wideband information providing baseline conditions and subband information providing frequency-selective adjustments. This structured feedback enables the eNB to dynamically adjust MIMO parameters while maintaining manageable control complexity through standardized reporting formats
Solution Approach 2:
The patent applies preliminary action by having the UE pre-calculate and report recommended MIMO parameters (PMI and RI) along with CQI based on channel measurements. The UE performs preliminary optimization of transmission parameters and provides recommendations to the eNB, which then makes final scheduling decisions. This preliminary action reduces the real-time control complexity at the eNB while maintaining high transmission efficiency
Data Source
AI summary
A method and a device for reporting channel quality information are provided by the present invention, the method comprising that: measuring, by a user equipment (UE), Channel State Information-Reference Signal (CSI-RS) according to the configuration information of the CSI-RS, to acquire a downlink channel transport matrix (101); determining, by the UE, Channel Quality Indicator (CQI) of a frequency domain reporting unit according to the number of CSI-RS ports and the corresponding transmission scheme of the Physical Downlink Shared Channel (PDSCH) used when determining the CQI, and the downlink channel transport matrix acquired by measurement (102); reporting, by the UE, the determined CQI to network side (103). The present invention can realize measurement and reporting of CSI-RS-based channel quality information on the basis of non-Precoding Matrix Indicator (PMI) feedback transmissions.