What’s next for test and measurement?—NTN, 5G-Advanced, 6G

With the continued evolution of 5G, close-in priorities for operators are understanding the why and how of 5G-Advanced, working with satellite providers on Non-terrestrial networks (NTN), and setting the stage for the commercialization of 6G in the 2030 timeframe. And before any of this can make much of an impact in the real world, it all has to go through rigorous (and ongoing) test and measurement processes. Experts at the recent Test and Measurement Forum (available on demand here) took up key considerations in this dynamic technological landscape. 

NTN for IoT, broadband and direct-to-cell communications

Starting with NTN, NI Fellow Marcus da Silva noted the variability in how NTN will be used, including for internet of things (IoT) use cases, satellite-based broadband to a dedicated terminal like SpaceX’s Starlink service, and direct-to-cell communications like the AT&T/AST SpaceMobile and T-Mobile US/SpaceX tie ups. Da Silva called out the need “to deal with huge Doppler shifts…and then you also have to deal with much longer latencies.” 

VIAVI Director of RF and Wireless Architecture Ian Wong mentioned that using commercial devices for satellite-based communications brings up important questions around link budget and transmit power from the handset. “At the end of the day, there’s a strong impetus to be able to support this with regular UEs,” he said. “I think that’s going to be the key challenge. And again, for all things, whether it’s data access or IoT, I think it’s a very similar challenge. 

The test and measurement piece of NTN requires specialized equipment. Wong cited work with Rohde & Schwarz to pair that firm’s NTN device tester with VIAVI’s network tester. “We needed to emulate the UEs on the ground as they interact with the satellites in the air,” Wong said. “And so we are actually modeling that accurately to enable…almost like as an NTN testbed. So there’s a lot of interest out there for people are just trying to understand…the issues that this network can encounter, and also what types of applications can actually be run with that network.” 

5G-Advanced for machine-type connectivity

Before we get to 6G, 5G-Advanced will hit the scene with a number of system-level enhancements and new features around indoor positioning and time-critical services among others. 5G-Advanced starts with 3GPP’s Release 18 and will continue to be refined in subsequent releases. 

Da Silva rightly pointed out that human cellular connections are approaching a point of saturation, meaning continued growth comes from connecting machines. In fact, he said, “We already have more machines being connected than we have people.” And this speaks to some of the goals of 5G-Advanced. “Latencies are no longer necessarily people latencies,” he said. “You may need robotic latencies, which may be much shorter than people latency…I think we’re seeing that shift from people-to-people connection to machine-to-machine connection. And again, Release 18 goes part of the way there.” 

Wong called out that given the trajectory of 5G monetization, operators are “very cautious in terms of additional spending.” So continued network capex needs to have a straight line to lower operational costs and, ideally, new service revenues. A lot of this could potentially come down to AI-enabled, more automated networks which is a focal point of Release 19. “I think there’s a lot of pragmatism that’s happening,” he said…There’s going to be new use cases. We want to support that to expand the serviceable market with verticals and private networks, etc…But I think there’s definitely a lot of things that we can do to support our operator customers today to make the network more efficient and more cost-effective to operate.” 

New G, new spectrum, new features, new test and measurement methodologies

With 5G, key spectrum bands were divided into FR1 sub-6 GHz and FR2 from 24 GHz to 52 GHz. While 6G is still some ways out, research, development and testing are ramping up. On the spectrum side, the so-called upper-mid band, FR3 frequencies in the 7 GHz to 24 GHz range are emerging as the likely range for wide-area 6G coverage. 

Wong said the current test and measurement focus is “how we can leverage that” FR3 spectrum. Other areas of study are artificial intelligence (AI) and machine learning (ML) “from the air interface all the way up to network management [and] optimization…And finally, let’s call it new use cases, new ways to monetize, is always something that is top of operators’ minds. And also energy efficiency.” 

This idea of 6G as AI-native suggests bringing AI into the physical layer which suggest new types of device and infrastructure testing. Given NI’s expertise in device testing, da Silva said, “one of the issues that we are having to face and haven’t completely answered yet, is the fact that if you have an AI/ML-enabled device, it is learning as it goes. Its behavior is not necessarily deterministic…So we’re looking at the need to move from measuring parametrics on a device…to measuring a whole bunch of different parameters, different behaviors, and creating a map of what looks like a good device versus a bad device. And one of the things this brings to mind is we may need to have AI to test AI.”  

What’s the long-term outlook for test and measurement? 

Whether it’s test and measurement for Open RAN networks, end-to-end AI services, NTN, 5G-Advanced, 6G, some combination of those or something else all together, one of the big points of this particular panel, and of the forum in general, were that increasing complexities and more stringent requirements mean more testing, more measurement, more optimization, more everything really. 

“I think the takeaways I would say I’d like to impart,” Wong said, “is clearly we, as a vendor community, have to come together to really address these…pressing issues of the day. Our telecoms market, it’s not in that upswing, as we all know. So we have to think about ways of trying to be more efficient. How do we address these issues that our operators are seeing? And I think we need the collective brainpower of the industry to really help achieve that.” 

Da Silva ended on one of the core concepts of test and measurement: “We are trying to shoot ahead of the duck, so to speak.” To the clearly increasing level of network and service complexity operators have to navigate, “As a test equipment vendor, the more issues they have, the more business we have.”