MU-MIMO Beam Selection for Interference Mitigation
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Solution Overview
Problem
In MU-MIMO systems, high spatial channel correlation among user terminals leads to interference between streams, reducing overall throughput.
Innovation Solution
A radio base station is configured with a beam selecting section to compute beam-selection reference parameters based on beam information from user terminals, selecting appropriate beams and a user terminal selecting section to choose target terminals for these beams, optimizing beam and terminal selection to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple user terminals are connected during the same period in MU-MIMO, then the throughput of the radio communication system is improved, but when the channel spatial correlation among connected user terminals is high, the streams for the user terminals interfere with one another, causing the throughput to decrease
Solution Approach 1:
The base station performs preliminary channel measurement and spatial correlation analysis before establishing MU-MIMO connections. By pre-evaluating the channel conditions and spatial correlation between user terminals, the system can proactively select compatible terminals for multiplexing, preventing interference before it occurs. This preliminary assessment enables the system to optimize user terminal pairing and maintain high throughput while avoiding harmful interference.
Solution Approach 2:
The system implements feedback mechanisms where user terminals report channel state information and beam quality metrics back to the base station. This feedback enables the base station to continuously monitor spatial correlation and adjust user terminal selection dynamically. When spatial correlation becomes too high and interference risk increases, the feedback loop allows the system to reconfigure connections, ensuring optimal throughput while managing interference levels.
2Object-affected harmful factors
If beam selection is performed based on beam information from user terminals, then appropriate beams can be selected to reduce interference, but the computation of beam-selection reference parameters increases processing complexity
Solution Approach 1:
The beam selection process is segmented into multiple stages: initial beam sweeping, beam refinement, and final beam selection. By dividing the complex beam-selection task into smaller, manageable segments, the system reduces processing complexity at each stage while still achieving optimal beam selection. This segmentation allows the base station to handle beam information from multiple user terminals efficiently without being overwhelmed by computational demands.
Solution Approach 2:
The system performs partial beam selection by focusing computation on the most promising beam candidates rather than evaluating all possible beams exhaustively. By applying partial action, the base station achieves sufficient interference reduction through beam selection without incurring the full computational cost of exhaustive search, thus balancing performance improvement with processing complexity constraints.
Data Source
AI summary
Radio base station 10 configured to perform MIMO transmission with user terminals 20 includes: beam selecting section 100 configured to select at least one used beam from among a plurality of beams based on beam-selection reference parameters to be computed based on beam information transmitted by user terminals 20; and user terminal selecting section 102 configured to select, from among at least one of user terminals 20 which has selected the at least one used beam, at least one of user terminals 20 to be a target for the at least one used beam.