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Spirent 5G Blog Series: New RAN

5G RAN Testing: Old Approaches Need Not Apply

When we talk about 5G, we tend to do it in the abstract. We refer to it as this giant, all-encompassing thing poised to solve all of mobile’s problems and deliver on its biggest opportunities. Of course, much of what is promised hinges on 5G radio technology. Whether high-bandwidth applications or Internet of Things (IoT) services with low latency requirements, a reliable and high-performance 5G Radio Access Network (RAN) is essential to successful service delivery. Let’s focus on that for a moment, because the unique demands placed on the 5G RAN often get lost in broader discussions.

The 5G RAN creates dynamic connections to people, things and industries using new air interface radio frequencies and software. It must support a multitude of new devices and chipsets and handle far more traffic at much higher speeds than today’s cellular networks. This is substantially more pressure and demand than we’ve ever put on a RAN. We’re in unchartered territory here. And that goes for testing too.

The complexity and dynamic aspects of 5G make traditional RAN testing and assurance impractical and cost-prohibitive. In fact, it necessitates an entirely new approach.

5G Signals New Test Challenges

So what exactly needs to change to conduct accurate RAN testing for 5G? Well, just about everything. Here’s a high-level look at some of the key elements:

  • 5G New Radio (NR) air interface supports new frequency band ranges that include frequencies in the sub 1GHz low-band, sub 6GHz mid-band and 24 GHz+ mmWave high-band. Because of the high levels of integration where devices implement antenna arrays and due to the use of millimeter wave frequencies traditional testing using a physical cable connection is no longer feasible for many cases. Testing using radiated Over the Air (OTA) methods will become essential.
  • New functionality such as Associated Adaptive Antenna system (AAS) using 3D Beamforming and Massive MIMO (Multiple Input and Multiple Output) technology means the complexity and cost of traditional testing is no long practical or cost efficient. Traditional testing of Radio antenna arrays was based on a conducted (cable) connection to the array elements. This was reasonably practical so long as the array only consisted of a limited number of elements. Massive MIMO in 5G can have as many as 256 array elements or more, requiring a large number of radio channels. Beamforming, for its part, means that the array elements serving the device can dynamically change. As a result, there is a need for an innovative approach for conductive testing of Massive MIMO that provides an economic and practical way to test the performance in a lab environment.
  • Cloud RAN, Edge Computing and Control & User Plane Separation (CUPS) bring Cloud and virtual networking to the heart of the Radio network but telco Cloud has stringent requirements compared to Public Cloud. Virtualization is a critical factor for 5G Cloud-RAN, where the Radio processing (Baseband) can be distributed from the lower levels hosted on the physical Radio tower heads and pooled in edge cloud data centers. Cloud-hosted Radio (baseband) processing needs unique capabilities around time-sensitive networking, acceleration, and availability, which current cloud architectures cannot deliver. The business case for 5G depends on cost-efficiently utilizing large numbers of urban small cell sites while moving the costly and complex processing to a shared, centralized, and cloud-hosted environment.

Real-world emulation simplifies 5G RAN test and assurance

In short, 5G requires affordable, scalable and repeatable test methodologies that can deliver services faster, simpler and more cost effectively. The new RAN is more complex, more dynamic, more beam-centric and more distributed than earlier RANs. It must also operate efficiently with large numbers of and many different types of devices.

Therefore, simplifying 5G RAN testing requires intelligent automation, network and traffic emulation, and new test methodologies. Network and traffic emulation can simplify the complex testing of 5G RAN. Test emulation imitates, replicates, or reproduces an exact scenario and context. A network emulator can test the performance of a real network and can test network functions and services that are physically unavailable or are too complex and costly to configure and access.

5G RAN emulation includes:

  • Radio Channel Emulation: Emulates 5G RF channel frequencies and densities and Massive MIMO and beamforming technologies to simplify the prototyping and testing of 5G radio equipment and devices.
  • Advanced Channel Modelling: allows for the simple creation of highly complicated Radio scenarios including real-world propagation, beam tracking and beamforming, high speed mobility and handover.
  • Network Emulation: Emulates the 5G core network and features to efficiently test the 5G New Radio (NR), validate key radio-to-core connectivity, and simplify the prototyping and design of industry-specific network slices.
  • RAN and Device Emulation: Emulates 5G base stations and millions of devices with complex traffic mixes to efficiently test that the core network can support 5G and deliver new capabilities such as CUPS.
  • Real World Emulation: Records and plays back real-world captured signals and traffic and replicates them in the test-bed through emulators to provide increased realism, repeatability and predictability.
  • Impairment Emulation: Emulates network impairments to validate how the network behaves, thereby gaining insight into how best to configure and architect the network.

Emulation is critical in 5G RAN testing because it reduces the complexity and cost of testing, verification, and delivery of 5G through cost-effective, repeatable and predictable testing of real-world conditions in a lab environment.

Simplifying the complexity of 5G RAN testing

Simplification and automation of testing and assurance is critical for the 5G RAN. It is no longer effective to follow traditional test and assurance methodologies. While approaches need to be simplified, they will also expand considerably in nature. You will need a partner that can help you swiftly and accurately navigate the complexity.

Follow our 5G blog series and download our Simplify 5G white paper to learn more about how automation, emulation and new test methodologies can reduce the complexity and economics of testing, verifying and delivering 5G networks.

Check back for more 5G assurance insights and join in the conversation by contacting us below. We look forward to hearing from you.

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