It hasn’t always been clear exactly how much carriers like Verizon and AT&T are deploying C-RAN, a term that can refer to Cloud-RAN or Centralized-RAN. AT&T refers to it as Centralized RAN, and like rival Verizon it’s planning to deploy more of it.
AT&T revealed earlier this year that it had started deploying small cells using Centralized RAN architecture in San Francisco. That deployment is being replicated in other cities, enabling the operator to densify its network and lay the groundwork for 5G and beyond.
The plan is to install small cells on light posts and other infrastructure using a C-RAN architecture approach, meaning all the “brains” of base band units of each small cell or tower exist in one location. But while the technology is fine, the real challenge is the age-old one of getting things approved in the permitting process, according to Paula Doublin, assistant vice president, construction and engineering, at AT&T.
Among other things, Doublin is in charge of making sure AT&T’s network is prepared for the deluge of fans who converge in “temporary cities” for events like the recent Coachella music festival in Indio, California, where AT&T saw nearly 40 TB of data cross its network from Friday, April 14, to Sunday, April 23. Equal to more than 113 million selfies, that’s 37% more data than last year’s festival.
The demands for data just keep growing year after year for these kinds of events, and AT&T has to be prepared. Of course, it uses cells on wheels (COWs), a popular industry practice, but it’s also gotten creative in the antenna department, introducing what it calls the big Drum Set and Giant Eyeball antennas that provide 10-20 times the capacity of a single beam antenna.
Doublin has been involved in network planning for stadiums and structures like airports and retail malls for many years, but the demands continue to be astounding. For example, some of the early deployments were designed to deliver capacity for three years—but they ran out of capacity after just one year. There’s the saying, “build it and they will come,” and for capacity, that's along the lines of “build it and it will get used.”
“Sometimes I just shake my head and I go back and run the numbers, and I send the folks back, and I say, run these numbers for me again and sure enough, they’re right, and it’s just amazing” how much traffic the network carries, she said.
AT&T has been on an aggressive path toward virtualizing and using software-defined networking (SDN), and that’s showing up in the buildings that Doublin oversees. For example, around the Rockefeller Center area in New York City, there are two distributed antenna system (DAS) cloud systems that AT&T has built to serve about 11 of the buildings in that area.
The computing part of the system is in a centralized area. It’s essentially a DAS cloud. “We love them, they’re wonderful,” she said. “It’s essentially a data center. That’s how it looks, that’s how it feels and that’s really how it functions and it serves the network.”
What’s happening across the country is heterogeneous networks coming together just as many in the industry have been talking about. There are various, wide-ranging solutions at an operator’s disposal, whether it be C-RAN, DAS or traditional small cells and Wi-Fi— “all those technologies are truly, truly coming together,” she said. “It’s truly converged.”
Of course, there’s been talk in the industry about HetNets for years. “I think people get a little jaded to it,” she acknowledged. “There were some things in the industry that had to happen,” including software-defined networking. “Everything had to coalesce. And I think we’re there. We’re building more and more of them.”
There’s self-optimizing configuration as well, but Doublin said she doesn’t think it’s completely eliminating old-fashioned, manual optimization. One of these days it might become an entire self-optimization network architecture, but “I don’t think we’re totally there yet.”
The one factor that’s impeding progress is getting permission to place small cells. Sometimes it can be a relatively quick process, but other times it can take months or even years to get the approvals.
The issues are being worked on at several levels. Last month, the FCC adopted a Notice of Proposed Rulemaking (NPRM) to examine how state and local processes affect the speed and cost of infrastructure deployment, seeking comments on improving state and local infrastructure reviews, such as zoning requests.
Everybody understands the need from a 5G, C-RAN and small cell perspective that “we have to go faster,” she said.
In some parts of the country, the permitting process can be done in 35-40 days; other areas may take months or years to get the permits. In some cases, customers—rightfully so—are afraid of having something situated in their neighborhood—and they’ve seen images of bad implementations that worry them. Doublin doesn’t blame them; she’s vocal in her own community when proposals are made to change the environment.
“To me, that’s the long pole in the tent … the rest of it is pretty simple to do,” she said. “I wouldn’t confuse that with being easy to do, but we know how to do that. Getting the permission to do it is the hard part. But I understand that. I keep an eye out in my own neighborhood.”
AT&T’s philosophy is “if we wouldn’t have it in our own neighborhoods, we wouldn’t put that out there for anybody else,” she said. “It’s going to take a lot cooperation across the board” between carriers, third parties and local, state and federal bodies that make the rules. “It’s truly a village approach that’s being done,” she said. “I know there’s a lot of people working on it,” including representatives from local, state and federal levels.
That can be frustrating; on the other hand, when the process is over, the gear gets installed and customers come up afterward and say, “this is fantastic,” and it’s rewarding.
“I’ve got the best job,” she said.