User Terminal CSI Sharing for MIMO Spatial Correlation

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Solution Overview

Problem

In next-generation mobile communication systems like NR, high spatial correlation between antennas hinders effective MIMO signal separation, limiting throughput improvement due to lack of channel state information sharing between user equipment (UEs).

Innovation Solution

A user terminal is equipped with a control section to determine and share channel state information with other user terminals, enabling advanced MIMO processing by facilitating CSI sharing between UEs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If channel state information is shared between user terminals, then MIMO processing performance is improved, but device complexity and information security requirements increase

Engineering Contradiction:

Improvecommunication throughputVSAvoidCSI sharing mechanism complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The base station acts as an intermediary that collects CSI from multiple user terminals and distributes relevant CSI information to appropriate terminals. This mediator approach enables CSI sharing without requiring direct terminal-to-terminal communication, simplifying the overall system architecture while achieving the goal of improved MIMO processing through shared channel state information.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If advanced MIMO processing is applied, then throughput performance is improved, but the requirement for channel state information increases

Engineering Contradiction:

Improvethroughput performanceVSAvoidchannel state information availability

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent combines CSI from multiple user terminals to create a more comprehensive channel state understanding. By merging CSI reports from different terminals, the system achieves better channel state information availability that enables advanced MIMO processing techniques, directly addressing the information requirement for improved throughput performance.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If spatial correlation between antennas is high, then MIMO signal separation becomes difficult, but this is a physical constraint that cannot be changed

Engineering Contradiction:

Improvesignal separation capabilityVSAvoidspatial correlation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system implements feedback mechanisms where user terminals report channel state information back to the base station. This feedback enables the base station to adaptively adjust MIMO processing strategies based on actual channel conditions, including spatial correlation characteristics. By continuously monitoring and responding to channel state feedback, the system maintains reliable signal separation even when spatial correlation varies.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12143185B2User terminal and radio communication method

Publication Date: 2024.11.12 NTT DOCOMO INC

AI summary

A user terminal according to one aspect of the present disclosure includes: a control section that determines whether or not to share given channel state information with another user terminal; and a transmission section that transmits the given channel state information determined to be shared to the another user terminal. According to one aspect of the present disclosure, MIMO can be suitably used.