Beamspace Compression for Planar Antenna Arrays in O-RAN

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Solution Overview

Problem

Current O-RAN systems use one-dimensional discrete Fourier transform (1D DFT) for beamspace compression of beamforming weights (BFWs), which is suboptimal for rectangular planar antenna arrays, leading to energy leakage and performance degradation in massive MIMO systems.

Innovation Solution

Implementing two-dimensional (2D) or three-dimensional (3D) discrete Fourier transforms (DFT) for beamspace compression, tailored to the specific antenna array configuration, and coordinating transformation variants between O-DU and O-RU to optimize beamforming performance and reduce computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If one-dimensional discrete Fourier transform (1D DFT) is used for beamspace compression, then the implementation is simpler, but beamforming performance degrades due to energy leakage

Engineering Contradiction:

Improvetransformation complexityVSAvoidbeamforming performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent transitions from one-dimensional DFT to two-dimensional DFT to match the rectangular planar antenna array structure. This dimensional change allows the transformation to properly account for both horizontal and vertical antenna elements, eliminating energy leakage while maintaining computational feasibility through the structured 2D approach.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If two-dimensional or three-dimensional DFT is used for beamspace compression, then beamforming performance improves by reducing energy leakage, but computational complexity increases

Engineering Contradiction:

Improvebeamforming performanceVSAvoidtransformation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the 2D or 3D transformation into multiple 1D transformations performed in sequence. By dividing the complex multi-dimensional DFT into successive one-dimensional transforms along different axes, the computational complexity is reduced while maintaining the performance benefits of the higher-dimensional transformation that matches the antenna array geometry.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If transformation is not tailored to antenna array configuration, then the system is more versatile, but energy leakage occurs leading to performance degradation

Engineering Contradiction:

Improvetransformation flexibilityVSAvoidsignal quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by tailoring the transformation dimensions and structure to match the specific antenna array configuration. Rather than using a universal transformation, the system adapts the DFT dimensions (1D, 2D, or 3D) and parameters to the local characteristics of the antenna array, ensuring optimal performance for each specific configuration while maintaining overall system versatility.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12556246B2Beamspace compression in an open-radio access network

Publication Date: 2026.02.17 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A first network entity of a communications network can generate compressed beamforming weights (“BFWs”) based on a transformation configuration. The transformation configuration can be based on one or more parameters of an antenna array associated with a second network entity of the communications network. The one or more parameters can include a parameter that is separate from a total number of antenna ports in the antenna array. The first network entity can further transmit an indication of the compressed BFWs to the second network entity via a fronthaul between the first network entity and the second network entity.