BARCELONA – Verizon has of course generated its fair share of chatter at Mobile World Congress thanks to its recent 5G trial announcement. But to find out more about the importance of the trials for Verizon’s 5G roadmap, and get the carrier’s thoughts on a shift to TDD and virtualization, we sat down with Sanyogita Shamsunder, Verizon’s Director of Network Infrastructure Planning.
According to Shamsunder, the 5G trials are about more than just testing fixed 5G in real world situations – they’re about data gathering. That data, she said, will not only allow Verizon to figure out what works and what doesn’t in fixed wireless, but it will also apply to mobile use cases as well.
“This is really the first proving ground on how millimeter wave with beamforming and all that works in various environments,” she said. “Like with anything else 5G is a technology that will serve multiple use cases, like IoT and broadband. And if you think about it, fixed wireless is enhanced broadband. Whether it’s mobile or fixed, a lot of our customers today use a phone sitting down in their home in their offices. So, it’ll slide right into a broader use case of mobility.”
Additionally, Shamsunder said feedback from the customer premise equipment used in the trials can also be used by Verizon’s vendor partners to help in the next stages of product development.
When it comes to infrastructure rollouts, Shamsunder indicated small cells can offer savings and efficiency by virtue of not requiring trench digging, but said there are other challenges – permitting among them. The carrier, she said, has already run into this in siting for its trials, but noted Verizon is working with municipalities and local governments to simplify the process.
As software defined networking and network function virtualization are critical pieces in the 5G puzzle, Shamsunder confirmed Verizon has already begun the virtualization process with its network core.
“With software defined networking and NFV we can channel the resources of the network,” Shamsunder said. “We are on the path to virtualization with a lot of our core network, and even today with our 4G network. That provides a lot of flexibility for us. We have several parts of our network which are already virtualized and then as we go to 5G, virtualized network is the only way we want to be deploying 5G, including parts of the radio network. We’re talking about things like (virtualized RAN) and (extensible RAN) and we’re working with 3GPP and all the standards bodies to have the flexibility to build a software-based RAN as well as core.”
TDD vs FDD
Though it was suggested earlier this week that TDD offers carriers an advantage through earlier deployments of technologies like massive MIMO, Shamsunder pushed back on that notion by noting that it depends on the frequency range.
In the lower bands, Shamsunder said FDD and TDD each have their own benefits, with FDD offering simplicity while TDD requires more coordination is up against more interference. When it comes to higher frequencies, though, Shamsunder agreed TDD will be king.
“Any technology at higher frequencies is probably going to be TDD because it’s easier to build, and MIMO is a requirement to make things work on millimeter wave and when talking about massive MIMO TDD lends itself somewhat easier,” she said.