Are CBRS private networks an alternative to DAS?

Private cellular networks that use unlicensed CBRS spectrum are at times pitched to enterprises as the best of both worlds, combining price points that can approach those of Wi-Fi networks with the security, reliability and range of cellular. What does this mean for distributed antenna systems (DAS), the traditional in-building wireless solution used by large venues to improve indoor cellular coverage and capacity?

This was the topic recently addressed by a panel at the Connect (X) conference in Denver, featuring speakers from American Tower, CommScope, Tessco and Tillman Digital Cities. The panelists agreed that CBRS private networks are not currently a viable alternative to DAS for enterprises that want to make sure visitors to their building don’t lose connection to public carrier networks.

“If you are comparing CBRS private wireless versus DAS for purposes of indoor wireless, extending the public network, it is not a good use of your time, because CBRS can’t do it right now,” summarized CommScope’s Steve Wimsatt, senior director, strategic alliances and business development. He explained the solution is technically possible, but public carriers have not agreed to connect to private CBRS networks. 

Wimsatt expects the situation to evolve over time, and thinks carriers already see the value of CBRS spectrum. “Because of the economics it seems like this is a gift to the carriers,” he said, adding the cost of a CBRS network is typically less than half the cost of a DAS. 

Carriers often invest in DAS in large, high-profile venues to make sure their customers stay connected to their networks at sporting events, concerts and conferences. In contrast, passing a customer off to a neutral host CBRS network means the carrier loses visibility of the user and control of the experience. Nonetheless, carriers are kicking the tires. 

“All the carriers have completed full deployments of a successful neutral host trial, so they’ve gone that far along,” said Wimsatt. “It’s still working through the business process.” 

The business process may be complicated. Carriers can argue that by connecting their subscribers to a company’s CBRS network, they are delivering users who can be offered services by that company over the network. Companies can argue that by keeping users connected, they are helping the carriers take credit for a consistent network experience. 

Sherafgan Mehboob, CFO and head of corporate development at Tillman Digital Cities, outlined the way a neutral host CBRS network would work from an end user perspective. “If an organization put in a CBRS network and they were able to connect AT&T,  Verizon and T-Mobile users without those users needing a new SIM … then that private network could be used just like a DAS,” he said, adding “it’s not about to replace DAS.”

Dave Heitmann, director of technology development at Tessco, agreed. “DAS is king in the space,” he said, noting carriers still have concerns about handing off to CBRS networks, especially when it comes to critical communications.

“People from the CBRS industry are meeting with the mobile operators all the time to convince them that CBRS could be a very low-cost, very easy-to-deploy DAS alternative,” said Wimsatt. “Technically it’s been proven. Once it happens, it could be an easy way to deliver very high quality indoor coverage inexpensively.”

Amit Shah, director of engineering at American Tower, sees an opportunity to deploy private networks alongside DAS in large venues. While DAS extends the public network for venue visitors, private networks can support staff and internet of things operations. 

“As the use cases develop and they start deploying these networks in large venues, the deployment part of CBRS will become more and more clear and understood by the industry at large,” predicted Shah. “Once that happens that will … stimulate demand in second tier and third tier venues.” 

Tessco’s Dave Heitmann said demand for private networks has accelerated within the last six months, especially in the manufacturing sector. He cited use cases including halolens tools for training and video analytics for security.

Not all private networks use CBRS of course, and carriers are active in other parts of the private networks space. They use their spectrum and expertise to build networks for enterprise customers, and often manage these networks as well. 

Indoor CBRS private networks deployed so far typically support specific enterprise use cases, but some venues are talking to carriers about connecting their public networks. For now, participating in neutral host CBRS networks doesn’t seem to be a high priority for any of the major carriers. “The carriers will take their own sweet time,” Shah forecast.