Massive MIMO Array Emulation via Cross-Correlation Grouping

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Solution Overview

Problem

Classical MIMO array modeling and channel emulation are expensive and complex, and become computationally prohibitive for massive MIMO systems, especially when dealing with higher frequencies and multiple users, as they require hundreds of fading links to accurately represent the wireless channel.

Innovation Solution

The method involves calculating a complete correlation matrix for a massive MIMO channel, grouping base antenna elements by polarization, and applying a cross-correlation matrix to determine observed beamforming power and delay, allowing for the emulation of a tractable number of virtual elements that can simulate the behavior of a larger array, enabling efficient emulation and testing of massive MIMO systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If classical MIMO array modeling is used to accurately represent the wireless channel, then measurement precision is improved, but device complexity increases and becomes computationally prohibitive for massive MIMO systems

Engineering Contradiction:
Improvechannel modeling accuracyVSAvoidemulation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the massive MIMO array into multiple sub-arrays, where each sub-array is modeled separately with its own channel characteristics. This division reduces the computational burden of modeling the entire array as a single entity while preserving the essential spatial diversity and correlation properties needed for accurate channel representation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates virtual channel models that replicate the statistical properties and correlation structures of the physical massive MIMO channel without requiring full-scale physical emulation. These virtual models capture the essential channel behavior through simplified mathematical representations, reducing complexity while maintaining measurement precision.

Inventive Principle:
Principle #26Copying

2Productivity

If the number of base antenna elements is increased to support massive MIMO, then data rates are improved, but the number of fading links increases making the system computationally prohibitive

Engineering Contradiction:
Improvedata rateVSAvoidnumber of fading links
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple fading links into aggregated channel models that capture the combined effect of multiple antenna elements. By combining the channel responses of individual antennas into group-level or sub-array-level models, the system maintains the data rate benefits of massive MIMO while reducing the number of individual fading links that need to be tracked and processed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from modeling individual antenna elements in one dimension to modeling sub-arrays or groups of antennas in higher dimensions. This dimensional transformation allows the system to capture the collective behavior of multiple antennas through reduced-order models, effectively managing computational complexity while supporting high data rates.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If higher frequencies are used to increase bandwidth, then data rates are improved, but antenna element size decreases resulting in lower path gains

Engineering Contradiction:
ImprovebandwidthVSAvoidpath gain
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent adjusts channel modeling parameters to account for the frequency-dependent characteristics of massive MIMO systems. By modifying correlation lengths, path loss exponents, and antenna pattern parameters to match higher frequency operations, the system achieves accurate channel representation that compensates for reduced path gains, enabling effective utilization of available bandwidth.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10243628B2Massive MIMO array emulation
Publication Date: 2019.03.26 VIAVI SOLUTIONS LICENSING LLC
  • US10243628B2 patent drawing
  • US10243628B2 patent drawing
  • US10243628B2 patent drawing

AI summary

The disclosed technology relates to systems and methods for emulating a massive MIMO beamforming antenna array of arbitrary size—a channel model between a transmitter and a receiver, with one or more signal paths having respective amplitudes, angles of arrival, angle spreads, and delays. The disclosed technology includes defining a complete channel model H, calculating the correlation matrix for the channel, grouping the base antenna elements of the antenna array by combinations of signal and polarization, and calculating observed beamforming power of each group of the base elements, by applying a cross-correlation matrix to determine observed power signals and delay of each signal at each remote antenna element of the user equipment. Emulation includes supplying cross-correlated signals to remote antenna elements of user equipment during a RF test of the user equipment. Disclosed technology includes a channel emulator that generates output streams for testing user equipment for multiple users.