CSI-RS Transmission and Resource Allocation in FD-MIMO Systems
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Solution Overview
Problem
Current FD-MIMO transmission systems face challenges in efficiently transmitting and reporting CSI-RS for accurate channel state measurement and interference measurement, particularly in managing the overhead of CSI-RS resources and coordinating periodic and aperiodic CSI reports across multiple antenna ports.
Innovation Solution
A method and apparatus for transmitting CSI-RS in a MIMO antenna system, where a base station periodically transmits CSI-RS to a terminal, requests CSI reports, and configures CSI-RS resources to avoid overlap with existing transmissions, allowing for interconnection of periodic and aperiodic reports, and groups CSI-RS antenna ports to optimize beamforming and interference measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI-RS is transmitted for all antenna ports simultaneously, then channel state measurement accuracy is improved, but resource overhead increases
Solution Approach 1:
The patent divides the antenna ports into multiple groups and transmits CSI-RS for different groups in different subframes. This segmentation allows the terminal to measure channel state for each group separately while reducing the total number of simultaneous CSI-RS transmissions, thereby resolving the contradiction between measurement accuracy and resource overhead.
2Loss of information
If periodic CSI reports are configured for all antenna ports, then channel state information completeness is improved, but feedback overhead increases
Solution Approach 1:
The patent configures periodic CSI reports for different antenna port groups in different subframes rather than all ports simultaneously. This segmentation reduces the feedback overhead while ensuring that complete channel state information for all antenna ports is still obtained over time through multiple measurement opportunities.
3Measurement precision
If CSI-RS transmission occasions are increased for aperiodic reports, then channel state measurement accuracy is improved, but transmission resource consumption increases
Solution Approach 1:
The patent performs channel state measurement for aperiodic CSI reports using CSI-RS transmitted in periodic subframes before the actual aperiodic report is triggered. This preliminary measurement action allows the terminal to have accurate channel state information ready, reducing the need for additional CSI-RS transmissions specifically for aperiodic reports and thereby reducing transmission resource consumption.
Data Source
AI summary
A method in which a base station transmits a CSI (channel state information)-RS (reference signal) in a MIMO (multiple input multiple output) antenna system is provided. The base station periodically transmits a CSI-RS for first CSI to a terminal. The base station requests the terminal to transmit second CSI in a first subframe. When a CSI-RS occasion is configured, the base station transmits a CSI-RS for the second CSI to the terminal for a duration of the CSI-RS occasion from a second subframe or to the second subframe, which is a subframe after a first offset configured for CSI-RS transmission from the first subframe.