MIMO Antenna Array Alignment Using Phase Offset Estimation

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Solution Overview

Problem

In wireless communication systems, misalignment between antenna arrays leads to loss of orthogonality in modes like LoS-MIMO, resulting in signal loss and other disadvantages, especially in advanced systems like 6G wireless communication.

Innovation Solution

A method for determining and correcting misalignment conditions between transmitter and receiver antenna arrays by estimating linear and rotational offsets using phase measurements of reference signals, allowing for physical adjustments to align the arrays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antenna arrays are physically aligned without adjustment, then device complexity is reduced, but orthogonality is lost and signal quality deteriorates

Engineering Contradiction:

Improveorthogonality maintenanceVSAvoidalignment adjustment mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical alignment adjustment mechanisms with signal processing-based phase compensation. Instead of physically adjusting antenna array positions using motors or mechanical stages, the system estimates phase errors caused by misalignment and compensates for them through digital signal processing, thereby maintaining orthogonality without complex mechanical systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operational parameters of the antenna arrays by adjusting phase shifts in the signal domain. By estimating phase errors from reference signals and applying compensating phase changes, the system maintains orthogonality despite physical misalignment, avoiding the need for mechanical position adjustments.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If phase measurements are performed for alignment estimation, then alignment accuracy is improved, but measurement time and processing complexity increase

Engineering Contradiction:

Improvealignment estimation accuracyVSAvoidalignment calibration time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs alignment estimation using phase measurements of reference signals before actual data transmission begins. By completing the alignment calibration in advance, the system establishes accurate phase compensation parameters that can be used during normal operation without requiring continuous measurements, thus reducing overall time loss.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent maintains alignment accuracy by using the estimated phase compensation parameters continuously during data transmission. Once the alignment is estimated and compensated for using reference signals, the same compensation parameters are applied throughout the communication session, eliminating the need for repeated measurements and maintaining orthogonality continuously.

Inventive Principle:

Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Maintains orthogonality between transmitter and receiver arrays, improving communication efficiency, power consumption, reliability, spectral efficiency, data rates, and latency.

Implementation Method 1

measuring, based on receiving the first set of reference signals, one or more first phases for the one or more reference signals

Methodology Applied

Scientific EffectPhase measurement:

Implementation Method 2

receiving, at a first antenna of a first antenna array of the first device from a second antenna of a second antenna array of a second device, a first set of reference signals

Methodology Applied

Scientific EffectElectromagnetic wave propagation:

Data Source

PatentUS11894889B2Physical alignment for multiple input multiple output devices

Publication Date: 2024.02.06 QUALCOMM INC

AI summary

Methods, systems, and devices for wireless communications are described. A first device, such as a user equipment (UE) or base station, may receive, at a first antenna of a first antenna array, a first set of reference signals. The first device may measure the phase for each of the reference signals and estimate a linear offset between the first antenna array and a second antenna array of a second device that transmitted the reference signals. The first device may adjust an alignment of the first antenna array according to the estimated linear offset. The first device may receive a second set of reference signals, measure the phase for each of the reference signals, and estimate one or more rotational offsets between the first antenna array and the second antenna array. The first device may adjust the alignment of the first antenna array based on the one or more rotational offsets.