The rapid adoption of gigabit LTE on the path to 5G is one of several mega-trends shaping the way carriers plan, deploy, monitor and manage networks. The telecom industry is undergoing major transitions including the move from physical to hybrid to virtual networks built on network functions virtualization and software-define network solutions, the increasing convergence of wireless and wireline networks, and densification of both indoor and outdoor networks. Given these concurrent evolutions, the role of service assurance–using network data points to make sure subscribers receive the best possible quality of experience while helping operators get the most out of investments–is also evolving.
Service assurance for gigabit LTE
Kashif Hussain, director of marketing for Viavi Solutions, said, “As far as gigabit LTE is concerned, everything has to work together. From an RF perspective, the one thing you really need to make sure of is your RF signal integrity is there.” With 4X4 MIMO, 256 QAM, carrier aggregation and LAA, “Operators have to make sure they’re getting the most out of the investments they are making on these enhanced features.” Reiterating his earlier point, “To do that, RF signal integrity has to be there.”
In the move toward software control of networks, NFV and SDN are driving an evolution from physical networks to hybrid networks and, in the future, fully virtualized, cloud native, automated networks. “The key is service velocity,” Hussain said. “Of course the cost of maintaining a virtual network is less than maintaining a physical network, but you have to be able to assure those networks in a similar way. That cycle has already started. With 5G, that will be the first phase where you will see a lot of networks going virtual.” This transition will require a combination of physical instruments and virtualized probe and test agents.
Mentioning the massive investments service providers are making in fiber optic infrastructure, Hussain pointed out that fiber-deep networks are being leveraged for everything from long-haul data transport and backhaul to, in the case of distributed antenna systems and small cell clusters built on a centralized-radio access network architecture, fronthaul. “Fiber verification is very important. In the last few years, we’ve seen heavy investment on the fiber side for 5G because the pipe has to be bigger. Going from 4G to LTE Advanced Pro, you have to do similar kinds of things–there has to be hygiene of the network from an RF standpoint, from a fiber standpoint, from a cable standpoint–it all has to be tested, validated and assured.”
From a product standpoint, Viavi has brought to market NITRO (network integrated test, real-time analytics and optimization) solution, which Hussain described as enabling a service provider to “take a journey from a physical network to a virtual network. You can utilize the strength of your physical instruments that you have, then deploy virtual agents and combine the results of those two and get a more thoughtful outcome.” Going forward, “We are building more and more 5G components into it as the technologies are standardized.”
When it comes to the evolution of service assurance, “Automation is the fundamental aspect of it,” Hussain said. “We do not believe customers will have the bandwidth to manage their networks without NITRO. The goal is to reduce downtime, reduce truck rolls, and enable centralized management from the network operations center so it can be easier and cheaper.”
UE and network test and measurement for gigabit LTE
Passing on the benefits of gigabit LTE to end users means new devices that have to certified onto carriers’ networks and new network infrastructure, LAA small cells for instance, that have be deployed and optimized. For the test and measurement industry, that means a new set of requirements related to lab testing of user equipment and new complexities for field technicians tasked with ensuring operator networks are operating properly.
First, let’s look at the device-testing side. “There’s so many different combinations with carrier aggregation,” Tony Opferman, business development manager, mobile wireless, Rohde & Schwarz USA, said. “There is a significant amount of testing that is required to cover all the different combinations. We have done a good job automating those tests. That’s one of the hard requirements,” Tier 1 mobile operators are requiring of the larger telecom ecosystem. “There has been a big push in terms of automation of device testing in the labs.”
Opferman explained that the need for automation of device testing is two-fold. Operators want to reduce costs associated with lab-testing engineers and accelerate time-to-market for new devices. “That’s a trend we’re seeing among Tier 1 operators. The technologies are getting more and more complex. We’ve been seeing the number of test cases mushrooming over the past few years. That’s one of the big issues we’ve constantly heard from all the operators.”
To facilitate this accelerated device testing process, Rohde & Schwarz developed the R&S CMWflexx system. ZTE used the product to demonstrate the speeds of its ZTE Gigabit Phone, which supports carrier aggregation, 4X4 MIMO and 256 QAM. The Rohde & Schwarz USA solution measures downlink data speeds above 1 Gbps; it also supports testing for other applications including Cat M1, narrowband internet of things and LAA.
Beyond the UE, there’s a rapidly increasing number of network infrastructure elements needed to provide the gigabit LTE experience. This includes fiber-, copper- and CPRI-based connections for macro sites, small cells and in-building deployments including DAS and C-RAN small cell clusters, and this paradigm will only be further complicated as 5G networks harnessing millimeter waves come online.
“If you look back, a field technician may be tasked with testing 15 or 20 base stations,” Keith Cobler, industry marketing manager, mobile wireless, Rohde & Schwarz USA, said. “Densification with every generation of mobile phones has grown as you move forward. From the carriers there’s absolutely an effort to make the technicians more efficient in the field. We’re trying to make sure our test equipment is in lock step with the way technicians will work in the future.”
Cobler continued: “Today you really still have two schools of technicians in the field. The fiber technicians are very different than the RF technicians. A lot of operators haven’t bridged that divide. That’s a gap operators are trying to close. To make technicians more effective in the field, you have to have a tool set that’s portable, flexible and capable of doing a lot of different tests.”
Rohde & Schwarz uses its Android-based QualiPoc tool to enable field technicians to test voice and data quality, troubleshoot network problems and optimize RF environments. The smartphone-based tool covers multiple protocol layers as well as the IP stack and provides real-time data to represent end-user quality of service and quality of experience. QualiPoc probes feed QoS and QoE data into the web-based SmartMonitor to present a real-time overview of network conditions.
“You have to have some way of measuring the QoE at the point it’s being used and it has to be cost effective,” Cobler said. “Then you have to aggregate all that different information together to get a measure of quality of experience on a certain sector of your network. Opferman added: “From our perspective, LTE is not going away. LTE is going to be there for the next 10-plus years. It’s going to be a support mechanism for 5G. Gigabit LTE gets us to start thinking about some of the network changes that have to take place to support these higher data rates.”
For a deep dive into gigabit LTE, register for our upcoming webinar featuring insights from Rehbehn, as well as industry leaders from Qualcomm, Viavi and Anokiwave.