CSI-RS Transmission Decoupling for Accurate Channel State Reporting
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Solution Overview
Problem
In mobile communications networks, obtaining accurate and timely channel state information (CSI) is challenging due to overlapping CSI-RS configurations and the time required for new configurations, which can result in obsolete CSI, especially when dealing with coordinated antennas.
Innovation Solution
A method and system for transmitting CSI-RS using different configurations and timing across a group of coordinated transmission points, including non-hopping and hopping CSI-RS, to enable precise CSI reporting and decouple it from PDSCH transmission, allowing for improved CSI reporting without restricting PDSCH transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If CSI-RS are transmitted with extended periodicity to reduce configuration changes, then network complexity is reduced, but CSI becomes obsolete before next transmission
Solution Approach 1:
The patent implements dynamic CSI-RS transmission by allowing the network to switch between different transmission modes (periodic, aperiodic, semi-persistent) based on channel conditions and mobility. The transmission timing and configuration are adjusted dynamically to ensure CSI remains fresh while managing network complexity.
Solution Approach 2:
The patent changes key parameters including transmission periodicity, offset, and configuration indexing to resolve the contradiction. By adjusting these parameters dynamically, the system can transmit CSI-RS frequently enough to maintain freshness while avoiding excessive configuration changes that would increase complexity.
2Measurement precision
If multiple CSI-RS configurations are transmitted simultaneously from coordinated TPs, then measurement accuracy is improved, but interference between configurations increases
Solution Approach 1:
The patent segments the CSI-RS transmission by dividing coordinated transmission points into different groups, where each group transmits CSI-RS at different times or with different configurations. This segmentation reduces interference between configurations while maintaining measurement accuracy through coordinated measurements from multiple TPs.
Solution Approach 2:
The patent introduces configuration indexing and timing information as intermediaries to distinguish between different CSI-RS transmissions. These intermediaries allow the UE to identify and separate signals from different TPs and configurations, reducing interference effects while maintaining measurement precision.
3Productivity
If CSI-RS transmission is coupled with PDSCH transmission, then resource utilization is improved, but CSI reporting timing flexibility is reduced
Solution Approach 1:
The patent segments the downlink transmission by separating CSI-RS from PDSCH into independent transmission components. This allows CSI-RS to be transmitted at different times and configurations without being constrained by PDSCH scheduling, thereby maintaining resource utilization efficiency while gaining timing flexibility for CSI reporting.
Solution Approach 2:
The patent implements dynamic decoupling of CSI-RS from PDSCH transmission, allowing the network to independently control CSI-RS transmission timing and configuration. This dynamic independence enables flexible CSI reporting that adapts to different channel conditions without being restricted by data transmission requirements.
Data Source
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AI summary
There is disclosed a method of obtaining channel state information, CSI, with respect to a plurality of coordinated antennas. The method is performed in a control node. The method comprises transmitting, by said plurality of antennas, according to different CSI-RS transmit configurations and at different points in time, channel state information reference symbols, CSI- RS. At a first time instance a CSI report from at least one user equipment, UE, is received. Based on the CSI report being received at said first time instance, said received CSI report is associated with a specific CSI-RS transmit configuration of the different CSI-RS transmit configurations. A control node and a computer program are also disclosed.