UE, RAN, and Core Emulators

Testing Massive MIMO (Multiple-Input Multiple-Output) systems presents unique challenges due to their large number of antennas and complex beamforming capabilities. Effective testing requires solutions that can accurately emulate real-world scenarios and characterize performance.

The PROPSIM Massive MIMO Test Solution enables efficient testing and analysis of:

• user and signal performance with up to 8x8 spatial multiplexing MIMO
• up to 64-channel massive MIMO and beamforming configurations
• Open RAN Radio Units (O-RUs) and complete base station RF MIMO performance

5G networks are built upon an evolving architecture that includes both traditional RAN (Radio Access Network) elements and new Open RAN (O-RAN) deployments. To deliver diverse coverage and capacity, the networks consist of different architectures and radio types:

• Network Architectures: 
  • Non-Stand-Alone (NSA): Leverages existing 4G LTE core networks while adding 5G radio capabilities. 
  • Stand-Alone (SA): A pure 5G network with its own dedicated 5G core. 
• Radio Types (based on coverage and capacity):
  • Femtocells, Picocells, Microcells: Smaller, lower-power radios for localized coverage (e.g., inside buildings, dense urban areas).
  • Macrocells: Traditional, larger cell sites providing wide-area coverage. 
  • Massive MIMO Digital Beamforming Radios: Utilize a large array of antennas to direct signals precisely, improving capacity and efficiency. 
  • mmWave Hybrid Beamforming Radios: Operate at very high millimeter-wave frequencies, offering extremely high speeds over shorter distances, often requiring a combination of digital and analog beamforming.

A 5G network can be emulated by creating a controlled test environment that reproduces the behavior of real-world network elements and conditions.

This involves simulating the interactions of components such as the:

• radio access network
• core network
• user equipment
• traffic patterns
• mobility scenarios

By doing so, engineers can validate system performance, troubleshoot issues, and evaluate interoperability before deployment.

Network emulation also makes it possible to test extreme or hard-to-replicate conditions—such as high load, interference, or rapid handovers—ensuring that base stations and devices perform reliably in diverse situations.

Key Performance Indicators (KPIs) are crucial metrics used to evaluate the efficiency, quality, and reliability of 5G base stations (gNBs). Monitoring these KPIs helps ensure optimal network performance and user experience. Common KPIs include:

• Throughput: The actual data transfer rate (e.g., Mbps or Gbps) achieved in both downlink (gNB to UE) and uplink (UE to gNB). 
• Latency: The time delay for data to travel from source to destination, critical for applications like autonomous driving and industrial automation.
• Spectral Efficiency: How efficiently the available radio spectrum is used to transmit data, often measured in bits/Hz. 
• Error Vector Magnitude (EVM): A measure of signal quality, indicating how much the transmitted signal deviates from the ideal, impacting data integrity. 
• Adjacent Channel Leakage Ratio (ACLR): Measures the power leakage from a desired channel into adjacent channels, indicating interference levels. 
• Call Setup Success Rate (CSSR): The percentage of attempts to establish a connection that are successful. 
• Handover Success Rate (HOSR): The percentage of successful transfers of a mobile connection from one cell to another. 
• Power Consumption: The energy efficiency of the base station, increasingly important for sustainable networks.

Over-the-Air (OTA) testing is absolutely essential for 5G millimeter-wave (mmWave) base stations (gNBs) because of the unique characteristics of these high-frequency signals and the antenna technology used. Here's why: 

High Frequencies & Path Loss: mmWave signals (e.g., 24 GHz and above) experience significant signal loss when traveling through cables. This makes traditional "conducted" testing (where instruments are directly connected by cables) impractical and inaccurate.

Integrated Antennas & Beamforming: mmWave gNBs often feature highly integrated active antenna arrays that use advanced beamforming to direct signals. These antennas cannot be easily disconnected for cable-based testing. OTA testing allows the entire antenna system, including its beamforming capabilities, to be tested as a complete unit.

Realistic Environment: OTA testing in an anechoic chamber simulates a more realistic wireless environment, capturing the true radiated performance of the gNB, which is crucial for real-world deployment.

Keysight offers specialized OTA test solutions, including remote radio heads (RRHs) that can be placed directly in the OTA chamber, minimizing cable loss and improving measurement accuracy for critical metrics like EVM and ACLR.

RF network drive testing is a method of validating wireless devices and networks using real-world RF conditions, such as mobility, fading, interference, handovers, and geographic variation. It evaluates how devices and networks perform in live or realistically modeled environments rather than only in static, controlled lab setups.

In RF network drive testing, performance is assessed across actual network routes or environments, capturing how RF conditions change over time and location. This enables engineers to measure key performance indicators (KPIs) such as throughput, latency, handover success, RF quality, and user experience under realistic operating conditions.

RF network test drive testing can be performed:

• In the field, using live networks and drive routes
• In the lab, by replaying or modeling real drive test data to create repeatable test scenarios

This approach is commonly used to:

• Benchmark device or network performance
• Validate mobility and handover behavior
• Correlate lab results with field performance
• Reduce reliance on repeated field trials by enabling field-to-lab reuse of test data

As wireless technologies evolve — especially with 5G and beyond — RF network performance testing plays a critical role in complementing UE, RAN, and core emulation by ensuring that lab validation aligns with real-world network behavior.

You should use Cellular Virtual Drive Test Emulation when you need to recreate real-world mobility and RF conditions in the lab to validate, debug, and optimize network or device performance in a repeatable and controlled environment. It is best suited for development and pre-deployment workflows where engineers need to evaluate handovers, beam management, throughput, and user experience across identical scenarios without the cost and variability of field testing. Virtual Drive Test Emulation also enables replay of field-captured data to accelerate root-cause analysis and regression testing in the lab.

You should use RF Network Drive Test Solutions when you need to measure actual performance on live commercial networks. These solutions are designed for field-based testing, allowing operators and optimization teams to assess real user experience, coverage, mobility, and network KPIs during deployment, acceptance, benchmarking, and ongoing optimization. Because they operate in real environments, results reflect true network conditions but are not fully repeatable.

In practice, the two are complementary:

• RF Network Drive Test Solutions show what is happening in the live network
• Cellular Virtual Drive Test Emulation helps you understand why it is happening and fix issues efficiently in the lab

Together, they create a closed-loop workflow that connects field insight with lab validation, reducing time to resolution and improving network performance before and after deployment.