Open RAN Energy Efficiency

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The O-RAN Alliance Global PlugFest Fall 2024 had a focus on measuring energy consumption across various components of the O-RAN ecosystem to build a more sustainable mobile networking future. As the i14y Lab had an especially large number of scenarios related to that topic, we sat down with our own Ajesh Pulyaar-Keerthi, Open RAN Verification Engineer at the i14y Lab, to discuss the what and how of these scenarios.

Right at the beginning of our conversation, Ajesh pointed out that reducing and controlling energy consumption is very much in the center of attention of both operators and vendors. Which is why the PlugFest Fall 2024 key areas of testing included looking at the energy consumption of single CU/DUs and RUs as well as in End to End (E2E) scenarios. The scenarios tested ways to reduce energy consumption as well as finding reliable ways to measure and monitor energy consumption.

“The initiatives,” Ajesh told us, “primarily focused on testing energy consumption and achieving savings across key components, including the O-RUs, O-DUs, and the overall end-to-end (E2E) system. These tests evaluated hardware energy consumption as well as software. Also, the O-RU focused standalone energy consumption based on ETSI standard was one of the key advancements.”

Software – controlling energy consumption through RIC

One software designed to reduce energy consumption tested was the AiVader Energy Saving xApp. The xApp adopts the Network APIs approach to interact with Near-RT RIC services, using machine learning based optimization to predict cell load and identify energy-saving opportunities – like deactivating capacity cells during off-peak hours. It was tested with the VVDN RIC and VIAVI RAN Simulator. The major focus was still on integrating the E2 interface, which includes the onboarding of the xApp and RIC subscription messages. A second phase will see testing related to cell shutdown.

Ways to reduce energy consumption

Another test case involved measuring Analog Device’s O-RU energy saving features. The O-RU employs features like the Intelligent DTx/Micro Sleep helping to improve energy efficiency. It was tested using different traffic load scenarios (FULL/BUSY/MEDIUM/LOW), using a VIAVI and R&S O-RU Tester Solution with a configuration for WG4.CONF and Energy Efficiency testing. The test showed that this way significant energy savings can be achieved.

Monitoring

If you want to optimize, you need to be able to monitor, Ajesh pointed out during our conversation. So, monitoring power consumption using tools like Redfish and Kepler plays a crucial role in optimizing network operations, particularly in O-RAN environments. These tools provide granular insights into energy usage across various components, allowing for targeted improvements in energy efficiency without compromising network performance.

Redfish and Kepler offer different ways to monitoring. Redfish is an industry-standard API for managing servers that enables monitoring of power and thermal metrics. This helps network operators manage energy consumption effectively across different hardware configurations. Kepler is a Kubernetes-based energy monitoring tool, estimating power consumption by tracking CPU usage in containers and nodes. Although it focuses primarily on CPU-related energy consumption, it correlates well with other monitoring methods like IPMI and PDU data, providing a holistic view of energy usage within cloud-native environments.

These tools support the development of energy-efficient RAN configurations by enabling operators to adjust power allocation dynamically, optimize workload distribution, and balance energy savings with performance. And during tests at the PlugFest they were used to analyze power consumption under different traffic loads.

Advancing collaboration

So, this PlugFest showed some very helpful results on the way to more energy efficiency in mobile networks. As for the i14y Lab’s role in this, Ajesh added at the end of our conversation: “By creating a platform for testing, integration, and innovation and by fostering an environment that emphasizes openness, interoperability, and vendor-neutral collaboration, we facilitate the development of disaggregated network components that adhere to O-RAN standards,” adding that “The collaboration at i14y Lab accelerates innovation by offering resources like automated test frameworks, opportunities for integration testing, and lab-as-a-service capabilities.”

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