NZP CSI-RS Interference Measurement in DAS OFDM Downlinks
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Solution Overview
Problem
Conventional methods fail to efficiently measure interference between eNB and UE in Distributed Antenna System (DAS)-based mobile communication systems, leading to inaccurate signal-to-noise ratios and performance degradation.
Innovation Solution
A method and apparatus for measuring downlink interference in DAS-based LTE-A systems using CSI-RS and muting techniques to separately quantify inter-cell and intra-cell interference, allowing accurate determination of downlink data rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional interference measurement methods are used in DAS-based systems, then device complexity is reduced, but measurement precision deteriorates due to inability to separately measure inter-cell and intra-cell interference
Solution Approach 1:
The patent segments interference measurement into two distinct components: inter-cell interference measurement using CRS from serving cell, and intra-cell interference measurement using CSI-RS from other antenna groups. This segmentation allows separate measurement of different interference sources, improving overall measurement precision while maintaining manageable system complexity through dedicated measurement resources for each interference type.
2Measurement precision
If CSI-RS and muting techniques are used to separately measure inter-cell and intra-cell interference, then measurement precision improves, but device complexity increases due to additional reference signals and measurement configurations
Solution Approach 1:
The patent employs CSI-RS with multi-functionality: it serves both as a channel state information reference signal for general channel estimation and as an intra-cell interference measurement resource when transmitted by non-serving antenna groups. This universal approach allows the same reference signal structure to fulfill multiple purposes, improving measurement precision without proportionally increasing system complexity.
Solution Approach 2:
The patent implements periodic transmission of CSI-RS by antenna groups in a coordinated manner, where antenna groups transmit CSI-RS periodically at different time instances. This periodic action pattern allows the UE to measure intra-cell interference at specific time intervals while receiving data from the serving antenna group, achieving accurate interference measurement without continuous additional signaling overhead.
3Reliability
If separate interference measurement for inter-cell and intra-cell interference is implemented, then reliability of downlink transmission improves, but ease of operation deteriorates due to complex interference measurement set configuration
Solution Approach 1:
The patent implements a feedback mechanism where the UE measures interference on configured interference measurement resources and reports channel state information including interference measurements back to the eNB. The eNB uses this feedback to adjust transmission parameters, antenna group configurations, and resource allocations, thereby improving downlink transmission reliability while the automated feedback loop reduces the operational burden of manual interference management.
Data Source
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AI summary
A method and apparatus for transmitting first configuration information for a channel measurement and second configuration information for an interference measurement, wherein the first configuration information indicates a first non-zero power channel state information reference signal (NZP CSI-RS) resource for the channel measurement and the second configuration information indicates a second NZP CSI-RS resource for the interference measurement, transmit an NZP CSI-RS associated with the first NZP CSI-RS resource, and receive channel state information based on measured channel and interference based on the first configuration information and second configuration information, wherein the first configuration information and the second configuration information indicate the first NZP CSI-RS resource and the second NZP CSI-RS resource among a plurality of configured NZP CSI-RS resources, wherein the interference from the second NZP CSI-RS resource for the interference measurement is identified based on a received power of a CSI-RS associated with the second NZP CSI-RS resource.