UE Antenna Pair Selection Using Mutual Isolation for MIMO

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In wireless communication systems, simultaneous operation of multiple transmitters on a device leads to cross-coupling of transmit powers, resulting in adjacent channel leakage, error vector magnitude, and emissions degradation, which are mitigated by power back-off but reduce the gain from MIMO or Tx diversity.

Innovation Solution

Selecting an antenna pair with maximum mutual isolation to reduce coupling between transmitters, thereby minimizing ACLR and EVM, and enhancing UL throughput and resource efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If power back-off is applied to mitigate cross-coupling effects, then emissions requirements are met, but MIMO or Tx diversity gain is reduced

Engineering Contradiction:

Improveemissions complianceVSAvoidMIMO/Tx diversity gain

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary measurement of antenna isolation characteristics before transmission. The UE measures the isolation between different antenna pairs and stores this information for future antenna selection, thereby preparing in advance to avoid cross-coupling issues without needing power back-off during actual transmission

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes the antenna configuration parameter by selecting different antenna pairs based on measured isolation characteristics. Instead of reducing power to meet emissions requirements, the system switches to an antenna pair with sufficient isolation that naturally meets the emissions requirements while maintaining full transmit power for optimal MIMO performance

Inventive Principle:

Principle #35Parameter changes

2Productivity

If multiple transmitters operate simultaneously, then MIMO or Tx diversity gain is achieved, but cross-coupling causes ACLR and EVM degradation

Engineering Contradiction:

ImproveMIMO/Tx diversity gainVSAvoidACLR and EVM performance

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically changes the antenna configuration parameter by selecting optimal antenna pairs based on measured isolation characteristics. This parameter change enables simultaneous transmitter operation with maintained ACLR and EVM performance by avoiding antenna pairs with poor isolation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements feedback by measuring antenna isolation characteristics and using this information to select appropriate antenna pairs. The measured isolation data feeds into the antenna selection decision, creating a closed-loop system that maintains signal quality while enabling MIMO operation

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250373317A1Antenna selection based on mutual isolation

Publication Date: 2025.12.04 QUALCOMM INC

AI summary

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may select, based at least in part on antenna isolation information for the UE, a pair of antennas from among at least three antennas available for transmission on the UE. The UE may transmit a communication using the pair of antennas. Numerous other aspects are described.