Interference Measurement in LTE-A MU-MIMO via DMRS and CSI-RS Segmentation
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Solution Overview
Problem
Current wireless communication technologies face challenges in accurately measuring interference, particularly in LTE and LTE-A systems, which limits spectrum efficiency and network capacity due to high pilot overhead and inadequate interference measurement capabilities, especially in Multi-user Multi-input Multi-output (MU-MIMO) scenarios.
Innovation Solution
The method involves a network side device sending interference measurement indication information to a terminal to perform interference measurement using various modes such as orthogonal or pseudo-orthogonal DMRS ports, specified resource elements, and 'power subtraction' techniques, allowing for improved interference measurement and demodulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CRS is used for pilot measurement and demodulation in LTE system, then channel estimation can be performed, but pilot overhead becomes large and interference cannot be estimated in MU-MIMO
Solution Approach 1:
The patent segments the reference signal into two independent parts: DMRS for channel estimation and CSI-RS for interference measurement. This segmentation allows each signal to serve its specific function without interfering with the other, resolving the contradiction between accurate channel estimation and reduced pilot overhead.
Solution Approach 2:
The patent extracts the interference measurement function from the CRS and creates a dedicated CSI-RS signal for this purpose. By taking out the interference measurement capability and placing it in a separate signal, the system can measure interference accurately without increasing the overhead of the original CRS.
2Measurement precision
If CSI-IM signal is introduced in LTE-A Rel-11, then CQI measurement performance improves, but interference information of each layer cannot be measured and actual interference of data transmission timeslots cannot be reflected
Solution Approach 1:
The patent applies preliminary action by having the network side device mute DMRS ports in advance before data transmission. This creates dedicated measurement resources where the terminal can measure interference from all layers before the actual data transmission occurs, enabling complete interference information capture.
Solution Approach 2:
The patent uses muted DMRS ports as an intermediary mechanism. These ports serve as a mediator that allows the terminal to measure interference from multiple layers without the interference being transmitted through the normal data channels, thus preserving complete interference information.
3Object-generated harmful factors
If network side implements interference avoidance through precoding and coordinated scheduling, then interference can be compressed, but accuracy of channel state information feedback becomes critical and terminal pressure increases
Solution Approach 1:
The patent inverts the traditional approach by moving from network-side interference coordination (which requires accurate channel state information feedback) to terminal-side interference measurement. The terminal measures interference directly using CSI-RS and DMRS, eliminating the dependency on accurate feedback for interference compression.
Solution Approach 2:
The terminal performs self-service by measuring interference independently using the CSI-RS and muted DMRS ports. This self-measurement capability allows the terminal to obtain interference information without relying on network-side coordination or accurate channel state information feedback, reducing terminal pressure.
Data Source
AI summary
An interference measurement method, a network side device and a terminal device are disclosed. The interference measurement method includes: a network side sending interference measurement indication information to a terminal, and indicating the terminal to perform interference measurement, wherein the interference measurement indication information is used for indicating one or more kinds of the following information to the terminal: interference measurement modes used for performing interference measurement; and parameter configuration information used for interference measurement.