Distributed MIMO Terminal Grouping for Interference-Aware Multiplexing

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Solution Overview

Problem

Existing distributed MIMO systems face significant interference issues, including inter-subset and intra-subset interference, which degrade communication quality, particularly when using partial weight generation methods.

Innovation Solution

A control apparatus determines radio terminal subsets for spatial multiplexing by estimating interference levels and allocating resources based on interference degrees, allowing or excluding terminals to share resources based on interference thresholds to reduce both inter-subset and intra-subset interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If partial weight generation method is used to reduce computational complexity, then calculation load is reduced, but interference between radio terminals increases

Engineering Contradiction:

Improvecomputational complexityVSAvoidinterference between radio terminals

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent segments radio terminals into multiple subsets and divides the antenna array into corresponding subsets. Each subset processes signals independently with reduced computational complexity, while coordinating with other subsets to mitigate inter-subset interference. This segmentation allows the system to achieve lower calculation load while managing interference through structured division.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an interference coordination mechanism that acts as an intermediary between different terminal subsets. The control apparatus coordinates resource allocation and precoding across subsets, mediating the interference effects that arise from partial weight generation. This intermediary coordination enables the system to maintain reduced computational complexity while controlling overall interference levels.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If multiple radio terminals share the same time and frequency resources for spatial multiplexing, then resource utilization improves, but interference between terminals increases

Engineering Contradiction:

Improveresource utilizationVSAvoidinterference between radio terminals

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the set of radio terminals into multiple subsets that share time and frequency resources for spatial multiplexing. Each subset is assigned specific resource blocks, allowing high resource utilization while limiting interference within each subset. The segmentation enables parallel transmission across subsets with controlled interference boundaries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different precoding strategies and resource allocation policies to different terminal subsets based on their local interference characteristics. Each subset receives tailored weight calculations and resource assignments that optimize performance for that specific group while minimizing impact on other subsets. This local optimization enables high overall resource utilization with controlled interference.

Inventive Principle:

Principle #3Local quality

3Productivity

If radio terminals are grouped into subsets for MIMO transmission, then spatial multiplexing efficiency improves, but intra-subset and inter-subset interference occurs

Engineering Contradiction:

Improvespatial multiplexing efficiencyVSAvoidintra-subset and inter-subset interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments terminals into subsets and assigns dedicated antenna subsets to each group for MIMO transmission. This segmentation enables spatial multiplexing within subsets while creating natural isolation boundaries that reduce inter-subset interference. The structured division maintains high spatial efficiency while managing interference through physical and logical separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements feedback mechanisms where the control apparatus monitors interference levels between subsets and adjusts precoding weights and resource allocation accordingly. Terminal subset performance information is fed back to optimize the weighting schemes, enabling the system to adapt to changing interference conditions and maintain high spatial multiplexing efficiency while controlling intra-subset and inter-subset interference.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12470261B2Control apparatus, method performed by control apparatus, and non-transitory computer readable medium

Publication Date: 2025.11.11 NEC CORP

AI summary

If interference between a second radio terminal and at least one of one or more first radio terminals is estimated to be a second degree greater than a first degree and less than a third degree, a control apparatus determines that the second radio terminal is required to belong to the same radio terminal subset as the at least one first radio terminal in order to allocate time and frequency resources to the second radio terminal for spatial multiplexing transmission. On the other hand, if interference between the second radio terminal and at least one of the one or more first radio terminals is estimated to be the third degree, the control apparatus determines that the second radio terminal is not allowed to belong to any radio terminal subset and that the second radio terminal is excluded from the spatial multiplexing transmission on the time and frequency resources.