AT&T, Dish hail open RAN, T-Mobile not so much

One round of comments is in, and it’s mostly as one might expect: Open Radio Access Network (open RAN) is a good direction for the wireless industry, but the federal government should not mandate any particular technology on the road to open RAN.

That’s one of the themes from the comments filed with the Federal Communications Commission (FCC) as part of the agency’s inquiry into open RAN. In March, the FCC opened a formal discussion by way of a Notice of Inquiry (NoI), posing all sorts of questions for industry and others to ponder. Stakeholders as diverse as Google and Qualcomm submitted their thoughts, alongside AT&T, Dish Network, Verizon, T-Mobile, the Telecom Infrastructure Project (TIP) and many more.  

Some commenters took the opportunity to opine at length. For example, Ericsson’s comments run over 40 pages, similar in length to the Open RAN Policy Coalition. But unlike the self-described coalition’s position on open RAN, Ericsson has not always been at the head of the line. Indeed, Ericsson was more or less on the sidelines until joining the O-RAN Alliance in early 2019.

The O-RAN Alliance was founded in early 2018 by AT&T, China Mobile, Deutsche Telekom, NTT DoCoMo and Orange by combining the C-RAN Alliance and the xRAN Forum. Verizon joined the O-RAN Alliance later than AT&T but still counts as an early participant in the xRAN specification and overall open RAN movement. T-Mobile is currently listed as a member of the O-RAN Alliance, but it hasn’t been as committed to open RAN as its U.S. rivals (parent company Deutsche Telekom has been involved for many years).

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Ericsson and its Nordic competitor Nokia are part of the vendor lock-in that operators have been trying to break up with open RAN. Similar to Huawei and ZTE, their proprietary gear for many years required operators to get their infrastructure from a single source. With open RAN, the idea is to open up the supply chain to more vendors, including U.S.-based companies, providing operators with more choices.

Ericsson told the commission that it undertook its cloud RAN initiative when it did because “the time was right from a technology and business perspective. We urge the commission to recognize the openness evident in the marketplace today, and to forswear use of government mandates to drive the marketplace toward any particular vision of openness.”

Verizon reminded the FCC that a lot of work remains to be done by the technical groups within the O-RAN Alliance and standards bodies such as 3GPP. While there are numerous examples of open RAN being deployed around the world, there’s an important distinction to be made between greenfield networks and existing networks, the latter of which is going to take more time to implement.

After the C-band auction, Verizon announced that its suppliers will be providing open RAN equipment to support its C-band and millimeter wave 5G deployments by the end of this year.

But Verizon doesn’t believe that the choice for operators in the future should only be open RAN. “There may be circumstances – even when open and interoperable interfaces are widely available in RAN components – that the best choice is a vertically integrated, proprietary system,” Verizon said. “Wireless providers will be the best positioned to determine the right mix of vendors and technology to best serve their customers.”

Open RAN vs. vRAN

Some commenters made a point to recognize the difference between open RAN and virtualized RAN (vRAN). Both open RAN and vRAN can lead to better security, automation and other features, but distinguishing between the two concepts is important, according to Google's filing.

“Fundamentally, ORAN is the specification of open, standardized interfaces,” Google said. It allows radio networks to use components from different vendors and avoid the dreaded vendor lock-in, and it facilitates the use of artificial intelligence (AI) and machine learning (ML) tools to analyze and automate network functions.

“vRAN, by contrast, involves virtualization of the RAN or of a RAN component, such as on virtualized network servers. vRAN allows adoption of scalable and agile cloud practices that drive innovation. It is possible to build ORAN without vRAN (i.e., without virtualization). Indeed, many operators are doing so today until vRAN achieves the same performance as traditional RAN. Likewise, it is possible to implement vRAN (e.g., a virtualized baseband unit (BBU) or part of a BBU) on proprietary hardware,” said Google, which supports both open RAN and vRAN.

Verizon said it has launched commercial vRAN, including virtual distributed unit (vDU) and virtual centralized unit (vCU) functions using common off-the-shelf hardware. Its vRAN efforts run “parallel and overlap with its open RAN efforts,” the carrier told the FCC. Virtual RAN provides flexibility by disaggregating the baseband software from hardware and supports deploying at scale and management of the network, while open RAN allows for equipment from different suppliers to be combined, Verizon explained.

AT&T said it expects to incorporate O-RAN compliant equipment into its network within the next year.

As AT&T introduces open RAN into its network, “our goal will be maintaining the same high level of performance at scale,” the company said. “We are actively working in this direction.” For example, AT&T recently conducted trials and demonstrations with multiple vendors of an open front haul leveraging O-RAN specifications.

RELATED: AT&T moves forward on open RAN while T-Mobile takes cautious approach: Special Report

The industry likely will see a gradual introduction of open RAN into existing networks, and some deployments may still leverage traditional network infrastructure, AT&T said, noting that many 5G RAN deployments will be specific to the site environment or the particular needs of a customer.

Dish out ahead

Dish highlighted its first-hand experiences with open RAN. The company, which has invested more than $22 billion in wireless spectrum assets over the past decade, is staking its greenfield standalone (SA) 5G network on open RAN. Dish completed its first fully open RAN-compliant network communication in December 2020, along with vendors MTI, Mavenir and Nokia.

By adopting an open RAN model, Dish’s network will have “significant benefits over traditional vertical networks, including security, network slicing and services orchestration, and the integration of multiple open RAN vendors.”

To promote adoption and deployment of open RAN, the commission should grant at least a 12-month extension for carriers in the “Rip-and-Replace” program that want to replace covered communications equipment with open RAN solutions, according to Dish.

The satellite TV company isn’t in the “Rip-and-Replace” camp because it doesn’t have a legacy network, but Dish said an extension would give wireless carriers the incentive to consider open RAN solutions that will expand the telecom supply chain.

T-Mobile not as interested

T-Mobile, which did not say anything about the status of open RAN in its own 5G network deployment, took a decidedly more cautious approach when it comes to open RAN. T-Mobile’s comments fit with what its President of Technology Neville Ray has previously said about the technology: It’s not ready for prime time at T-Mobile.

Like others, T-Mobile said the commission should not mandate the use of open RAN networks. “The commission should take a ‘hands off’ approach to open RAN, neither mandating its use nor attempting to facilitate its development by regulatory fiat,” the “un-carrier” told the agency. “The commission has historically refrained from requiring the use of particular technologies and has consistently structured its rules to be technology and service neutral.”

T-Mobile also identified reasons open RAN might not be the best choice. “While intended to decrease security risks, open RAN may do the opposite,” T-Mobile said, adding that if the commission adopts open RAN specifications that deviate from what is being deployed today, it might actually weaken trusted vendors that don’t conform and reduce, rather than strengthen, supplier diversity.

“Fully deployed open RAN-based mobile networks in the U.S. in the near-term are only speculative at best,” T-Mobile told the agency. While Dish is often cited as an example, it’s still in a nascent stage of network development, and even Rakuten, one of the first companies to use open RAN as part of a fully virtualized cloud network, has experienced challenges in its implementation, including slow subscriber growth, according to T-Mobile.  

“While Open RAN may be feasible in ‘greenfield’ networks, it may not be possible to implement the technology in existing ‘brownfield’ networks, where deployed RAN components were not intended to operate in a multi-vendor environment. And it is likely to be more costly to do so,” T-Mobile said.