The deployment of the fifth-generation mobile network (5G) continues to progress around the world, with new services gradually becoming available, enhancing the user experience and enabling challenging applications.
It is important to realize that the 5G network is not just an increase in performance (in terms of upload and download speeds) over 4G technology, or a simple upgrade of existing standards and protocols. In addition to typical mobile phone applications, 5G technology will be able to support higher-level services and applications, such as self-driving cars, vehicle-to-vehicle and vehicle-to-everything communication (V2V and V2X), virtual reality (VR) and augmented reality (AR), streaming of high definition video, and IoT applications. The new features provided by the 5G network can be summarized as follows:
eMBB (enhanced Mobile Broadband): 5G higher bandwidth will allow a smooth and efficient use of applications such as augmented reality, video streaming, and video conferencing;
mMTC (massive Machine Type Communication): 5G will be able to manage massive connectivity (thousands of simultaneously connected devices and millions of connections) without overloading the network. This will allow efficient management of complex IoT applications, such as smart homes, smart cities, smart grids, and more;
URLLC (Ultra Reliable Low Latency Communication): This service will provide support for all applications requiring real-time behavior and extremely low latency such as factory automation, industrial control systems, self-driving cars, smart grids, and surgery robotics.
Due to the rapid pace of technological advancement and the high demands that 5G will impose on the network infrastructure, a comprehensive testing plan is required, from the lab to the field, and from the RAN to the core. In addition, operators and equipment vendors are adopting Open Radio Access Network (RAN) technology, including O-RAN ALLIANCE standards, to minimize infrastructure development costs and to lower the barrier to new product innovation.
As shown in Figure 1, 5G network testing involves three main phases:
Validation: The technology is validated in the lab, before its deployment.
Verification: The network and its services are verified in the field, through a proper field trial.
Visibility: This phase aims to assure, optimize, and monetize the network.
The deployment of 5G networks and solutions requires a test and measurement company that helps both vendors and operators to test their 5G telecom equipment. This involves not only wireless communication testing but also fiber optic measurements, field measurements with spectrum analyzers and more.
“When it comes to telecom testing, we test 3G, 4G, and 5G networks, including Open Radio Access Networks,” said Owen O’Donnell, Wireless Solutions manager for VIAVI Solutions, in an interview with EE Times Europe. “Operators and equipment manufacturers throughout the world are adopting Open RAN to minimize infrastructure deployment costs and lower the barrier to new product innovation.”
VIAVI Solutions said it has developed a comprehensive test suite with modules for lab validation, field deployment, and service assurance.
One thing to clarify is the difference between lab and field testing. The Lab is where the vendor developing a new base station or a 5G core network wants to test what has been developed, making sure it actually works according to the requirements or the applicable standards. Telecom standards, such as those developed by 3GPP, are evolving very quickly, and vendors need to develop their products to meet the new standards.
O’Donnell said, “Vendors need to verify that they have actually understood and implemented the standard correctly, and that’s where VIAVI Solutions comes in. So, we would help them go to a lab, and we would help them by emulating the elements that they don’t have.”
For example, if the vendor wants to test a base station, VIAVI can provide solutions which emulate the behavior of thousands of UEs (such as mobile phones), sending the relevant messages to the base station and testing that it handles those UE messages correctly. On the other side of the base station, a core network can be emulated, so that the base station forwards the call setup requests to the core network and gets the correct returns from it. The base station under test can thus be wrapped around with two VIAVI products, a UE emulator, and a core network emulator. That will help the base station manufacturers to ensure that their base station is working correctly from a standards compliance point of view.
“This test can all be done in the lab, where things can fail without affecting anyone in the live network,” said O’Donnell. “But then, when you go to the actual live network in the field, you need to do also other tests, such as beamforming tests.”
5G is supposed to give users a better throughput, more connections, and more IoT devices.
“Operators have specific KPIs they expect to meet, but we don’t know what those figures are until we go into the field and measure the real throughputs and the number of connections to the end base station,” said O’Donnell.
In 5G, core networks are completely different with respect to 4G core networks. There has been a complete redevelopment and redesign of the core network, and new elements have been added. The important thing is that those individual elements of the core network can now be supplied by different vendors.
“We need to make sure that all those elements interwork together, and then that they interwork together with real traffic,” said O’Donnell.
This is where TeraVM, one of the VIAVI lab-based tools comes in. TeraVM is an application emulation and security performance solution which delivers comprehensive test coverage for application services, wired and wireless networks. Figure 2 shows how TeraVM and other VIAVI tools can be used for validating the 5G SBA (Service Based Architecture) virtual mobile core and its components.
When people can’t access labs easily (This is especially true in times of pandemic, as happened recently with Covid-19), then they will move their testing to the cloud. So, they can access the system from their home, or from any location where they have an IP connection. To meet this demand, VIAVI has put its system tests solutions in the cloud. Logging on to Amazon Web Services, the user can select and reserve some instances, upload the test solution to those instances, and perform the testing on the cloud platform. The test solution will therefore only be used for as long as necessary, i.e. the time required to test the functionality.