MU-MIMO Terminal Feedback for Inter-Layer Interference
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Solution Overview
Problem
In MU-MIMO systems, existing technologies fail to effectively account for inter-layer interference, leading to performance degradation due to the inability of terminals to feedback Precoding Matrix Index (PMI), Channel Quality Indicator (CQI), and Rank Indicator (RI) that consider inter-user interference, resulting in inefficient data communication.
Innovation Solution
A method and apparatus that enable terminals to measure and feedback PMI, CQI, and RI considering radio channel conditions and inter-layer interference, allowing the base station to determine the number of layers supportable for MU-MIMO service, thereby improving communication efficiency by exchanging information on inter-layer interference and layer supportability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If terminals feedback PMI, CQI, and RI without considering inter-layer interference in MU-MIMO mode, then the feedback process is simple and fast, but the system performance degrades due to inaccurate channel state information
Solution Approach 1:
The base station performs preliminary actions by determining the number of supportable layers and calculating reference inter-layer interference values before terminal feedback. This preliminary calculation of interference characteristics enables terminals to compensate for inter-layer interference when measuring channel state, improving feedback accuracy without significantly increasing processing complexity
Solution Approach 2:
The patent implements a feedback mechanism where terminals measure channel state values based on reference signals and the number of supportable layers, then feedback this information to the base station. The base station uses this feedback to determine actual supportable layers, creating a closed-loop system that progressively improves channel state information accuracy
2Device complexity
If the base station determines the number of supportable layers without exchanging interference information, then the system operation is simple, but the scheduling and resource allocation efficiency is reduced
Solution Approach 1:
The patent introduces channel state information and interference indicators as intermediary elements between the base station and terminals. These intermediaries carry information about inter-layer interference characteristics, enabling the base station to make more informed scheduling decisions without directly exchanging complex interference matrices between all nodes
Solution Approach 2:
The base station determines the number of supportable layers by changing and evaluating different layer configuration parameters. By adjusting the number of layers and recalculating interference characteristics, the system identifies optimal configurations that maximize scheduling efficiency while maintaining manageable operational complexity
3Ease of operation
If terminals measure channel state without considering the number of supportable layers, then the measurement process is simple, but the determined channel quality does not reflect actual MU-MIMO performance
Solution Approach 1:
The patent applies local quality by having terminals measure channel state specifically based on the number of supportable layers determined by the base station. Instead of a single uniform measurement, the measurement process is localized to specific layer configurations, allowing terminals to assess channel quality under actual MU-MIMO operating conditions
Solution Approach 2:
The base station performs preliminary determination of the number of supportable layers before terminal measurement. This preliminary action provides terminals with the necessary context information to perform accurate channel state measurements that reflect actual MU-MIMO performance characteristics
Data Source
AI summary
A method and apparatus of exchanging information on the number of layers which is supported commonly between the base station and the terminals in Multi-User Multiple Input Multiple Output (MU-MIMO) environment is provided for performance enhancement. The communication method of a terminal in a wireless communication system according to the present disclosure includes receiving a reference signal and information on a number of layers supportable simultaneously from a base station, measuring a channel state value based on the reference signal and the number of layers, determining whether the measured channel state value fulfills a minimum required channel state value, and transmitting, when the measured channel state value fulfills the minimum required channel state value, a value determined based on the measured channel state value to the base station.