Power Monitoring for Energy Efficient 5G/6G with OAI and USRP

Application Note Number and Authors

AN-844

Authors

Bharat Agarwal and Neel Pandeya

Executive Summary

Energy efficiency is becoming a critical KPI for 5G-Advanced and 6G systems, especially in Open RAN, AI-driven PHY, and Integrated Sensing and Communication (ISAC) testbeds.

Real-time power monitoring enables:

• Evaluation of baseband processing efficiency
• Measurement of RF front-end power consumption
• AI accelerator energy profiling
• Optimization of system-level energy-per-bit metrics

This application note demonstrates how to implement accurate power monitoring in a 5G/6G testbed using NI measurement hardware and software tools.

Demonstrator Scope and Overview

This demonstrator implements a measurement framework to synchronously monitor and measure power and energy consumption across multiple heterogeneous components of a wireless system.

Syncronized Power Monitoring for Wireless systems using Open-Air-Interface with NI USRP and NI cRIO (*Note: For the demo, the base station prototype is connected to a 5G prototype user terminal which is not shown on the block diagram.) ​

Device Under Test (DUT)

5G/6G Base Station Prototype, consisting of:

• Linux server (baseband processing platform)
• OpenAirInterface (OAI) base station stack
• NI USRP (RF front-end)
• External switchable power amplifier (PA)

1. 3GPP-Aligned Demo Use Case

Energy Savings via Enhanced Cell Sleep Mechanisms

• Demonstrates energy reduction at the base station power amplifier.
• Evaluates increased cell sleep opportunities.
• Quantifies real-time power savings during inactive traffic periods.

2. AI-RAN Demo Use Case

Energy Profiling of AI-Native vs. Traditional Receiver

• Measures energy consumption of:
  • AI-native base station receiver
  • Traditional (e.g., LMMSE-based) receiver

Key Feature of the Measurement Framework

All power and energy measurements are:

• Fully synchronized to a common time grid
• Aligned with the 500 µs slot grid of the 5G NR system

This synchronization enables:

• Slot-level energy analysis
• Accurate correlation between radio activity and power consumption
• Fine-grained energy profiling of PHY processing, RF transmission, and AI inference workloads

Demonstrator System Architecture

The diagram presents a Demonstrator System Architecture used for power‑aware testing of a 5G/6G Base Station Prototype (gNB) and NI USRP. ​

1. 5G/6G Base Station Prototype (gNB)

The DUT includes power sensors (GPU, CPU), a power supply, and an open-source 5G/6G stack from OpenAirInterface. It connects to NI USRP hardware and an external power amplifier. Power channels (AC/DC) are monitored for measurement.

2. NI CompactRIO Power Measurement System

• cRIO Controller 9047 for power calculation and data aggregation
• Measurement modules:
  • NI-9244 — AC voltage (400 Vrms)
  • NI-9238 — AC current (±500 mV)
  • NI-9229 — DC voltage (±60 V)
  • NI-9227 — DC current (5 Arms)
• Collects voltage and current measurements from gNB components

3. NI Data Recording Entity / Server

This Linux server handles:

• System configuration
• Test execution
• Data recording
• Data visualization

All measurement data is stored in a data lake with timestamps and metadata.

4. 5G User Terminal (UE)

The UE runs an open-source 5G stack from OpenAirInterface and communicates with the gNB via NI USRP hardware over a wired or wireless RF channel.

Overall Workflow

The gNB and UE communicate over RF. The CompactRIO system measures power data from the gNB and sends it to the centralized data server for recording and analysis.

Demonstrator Setup

The image shows a real‑world hardware setup corresponding to the demonstrator architecture. The numbered labels in the picture match three major system components. ​

1. Device Under Test (DUT): 5G Base Station

The left side of the setup contains the 5G base station prototype with an external switchable power amplifier. A computing platform equipped with an NVIDIA RTX 4090 GPU runs the 5G gNB software stack. Multiple cables connect the DUT to measurement equipment and RF interfaces.

2. NI cRIO Power Measurement System

The central upper part of the setup features the NI cRIO system with an attached breakout box for sensor connections. This equipment measures voltage, current, and power consumption from the DUT and forwards the data to the recording server.

3. Data Recording Entity

The central lower section includes the NI Data Recording Entity, responsible for data orchestration, logging, aggregation, and visualization. A monitor above shows dashboards and measurement results.

5G User Terminal (UE)

On the right side is the 5G User Terminal (UE), which acts as the RF counterpart to the DUT. It connects through RF interfaces for 5G communication testing.

5G Sub‑System Demo Configuration (gNB + UE)

1. Wireless Scenario

• Single link between one gNB and one UE
• Wired RF connection
• No interference from:
  • Neighboring cells
  • Other UEs

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Operating Band

• NR Band: n78

Waveform & Numerology

• Subcarrier Spacing (SCS): 30 kHz
• Waveform: CP‑OFDM
• Channel Bandwidth: 40 MHz
• Maximum PRBs: 106

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3. Downlink (DL) Scheduling

• Scheduled DL PRBs:
  • 20 PRBs
  • 80 PRBs
• Switch interval: Every 10 frames

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4. Uplink (UL) Scheduling

• Scheduled UL PRBs: 6 (kept low to ensure gNB Neural Rx real‑time performance)
• UL transmission bandwidth: ~2.16 MHz

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5. TDD Configuration

DL/UL periodicity: 5 ms

TDD Slot & Symbol Structure

Parameter	Value
nrofDownlinkSlots	7
nrofDownlinkSymbols	6
nrofUplinkSlots	2
nrofUplinkSymbols	4

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6. PUSCH Configuration

• Mapping type: B
• PUSCH duration: 13 OFDM symbols
• DMRS configuration:
  • Type 1
  • dmrs-AdditionalPosition = pos2
  • DMRS positions: Symbols 0, 5, 11

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