O-RAN Zero-Weight Beamforming for Selective MIMO Power Saving
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Solution Overview
Problem
The increasing energy consumption in radio networks, particularly at base stations, due to idle periods and fluctuating traffic loads, necessitates a solution to dynamically control power amplifiers in Radio Units (RUs) to reduce energy waste in Open Radio Access Networks (O-RAN).
Innovation Solution
Determine the number of Multiple-Input-Multiple-Output (MIMO) antenna elements required to serve User Equipment (UEs) and send a beamforming weight of zero to unnecessary elements via the control plane, disabling them to reduce power consumption in O-RAN Radio Units (O-RUs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If all MIMO antenna elements are kept active in O-RU, then network capacity and coverage are maintained, but power consumption increases significantly during idle periods and low traffic loads
Solution Approach 1:
The patent applies dynamics by making the antenna element activation state changeable. The O-DU dynamically adjusts the beamforming weights for different MIMO antenna elements based on real-time traffic conditions and UE locations. During idle periods or low traffic loads, the system dynamically sets beamforming weights to zero for unnecessary antenna elements, causing them to be disabled. This dynamic adjustment allows the system to adapt between high capacity mode (all antennas active) and energy-saving mode (selective antenna activation), directly resolving the contradiction between maintaining network capacity and reducing power consumption.
Solution Approach 2:
The patent changes the beamforming weight parameter from fixed non-zero values to dynamically adjustable values including zero. By modifying this critical parameter in the beamforming process, the system can selectively deactivate antenna elements without physically changing the hardware configuration. This parameter change enables the O-RU to reduce power consumption by setting beamforming weights to zero for antenna elements that are not currently needed, while maintaining the ability to restore full capacity when traffic conditions require it.
2Ease of operation
If beamforming weights are sent via user plane for antenna control, then control is simple, but control plane resources are consumed and latency increases
Solution Approach 1:
The patent introduces the control plane as an intermediary channel for transmitting beamforming weight information from the O-DU to the O-RU. Although the control plane adds some overhead, it provides dedicated, prioritized communication path that is optimized for control signals. The intermediary control plane ensures reliable and timely delivery of beamforming control information, enabling dynamic antenna element activation/deactivation decisions to be made efficiently without consuming user plane resources.
3Loss of energy
If dynamically controlling PA in O-RU is implemented, then energy savings are achieved, but system complexity increases due to additional control mechanisms
Solution Approach 1:
The patent segments the RAN functions according to O-RAN architecture, separating control functions (O-DU) from execution functions (O-RU). This segmentation allows the control plane to handle beamforming weight calculations and decisions independently from the O-RU's PA control. The O-DU determines which antenna elements need activation based on traffic conditions and UE locations, then transmits this information to the O-RU. This functional segmentation reduces the complexity burden on any single component while enabling coordinated energy-saving control across the distributed system.
Data Source
AI summary
Techniques for reducing power consumption in a radio unit are disclosed. The techniques include determining a number of Multiple-Input-Multiple-Output (MIMO) antenna elements of a MIMO antenna panel required to serve one or more User Equipment (UEs), identifying a number of MIMO antenna elements of the MIMO antenna panel not needed to serve the UEs. The techniques include sending, from an Open Radio Network (O-RAN) Distributed Unit (O-DU) to a O-RAN Radio Unit (O-RU), a beamforming weight of zero assigned to the MIMO antenna elements identified as not needed to serve the one or more UEs, the beamforming weight being sent in a digital domain via a Control plane (C-plane). The MIMO antenna elements assigned the beamforming weight of zero may be disabled thereby reducing the power consumption of the O-RU. Artificial Intelligence algorithms may be implemented to dynamically determine areas where the O-RAN should have more coverage or less coverage.