AT&T added at least one new open radio access network (RAN) vendor to its ambitious and Ericsson-based open RAN plan, though rivals are quickly moving to outflank the carrier’s network overhaul.

AT&T has signed agreements with Fujitsu and Mavenir to provide open RAN-compliant radios that will run on the carrier’s Ericsson-based open network platform. Those radios are designed with a lower profile that can be attached to existing utility and light poles in dense, urban environments.

Radio specifics include the supply of open C-band (3.7 GHz-4.2 GHz) radios supporting time-division duplex (TDD) with four-transmit and four-receive antennas (4T4R), and dual-band radios supporting band 25 (1.9 GHz-2 GHz) and band 66 (1.7 GHz-2.1 GHz) with frequency division duplex (FDD) 4T4R antennas. FDD spectrum is typically fixed in splitting its channel capacity evenly between the uplink and downlink, while TDD technology allows operators to adjust the uplink and downlink capacity of a spectrum channel based on need.

The Fujitsu angle cements that vendor’s long-standing work with AT&T’s open RAN program. The vendor was the only other vendor besides Ericsson to be named as part of AT&T’s initial open RAN announcement.

Fujitsu has also gained considerable open RAN opportunities from its ongoing work with operators like NTT DoCoMo, KDDI, and Dish Network in the U.S., and it has an optical networking legacy with AT&T.

The AT&T deal is perhaps more significant for Mavenir. While the vendor has been touted as a leading open RAN player, it has struggled to gain larger deals outside of its long-standing partnership with EchoStar/Dish/Boost Mobile. It has also been wobbling through various stages of financial viability.

AT&T COO Jeff McElfresh explained during a media question-and-answer session that network testing showed the two vendors as being “a little bit more advanced, little bit more mature, I should say, in their technology.”

One name obviously missing from the current AT&T open RAN vendor list is Samsung, which is considered by many analysts as a leading segment player. Samsung at the time of AT&T’s initial open RAN announcement said it was hoping to garner some business from AT&T.

“I think we’ll learn as we go where the opportunities might be if [AT&T does] move to a multivendor open RAN architecture, then we’d love to compete for business,” Alok Shah, VP of strategy and marketing for Samsung Electronics America’s networks business, told SDxCentral in an interview. “But I think it’s a little too early to tell.”

AT&T open RAN bolstered by Ericsson McElfresh’s maturity comment is important for the still coalescing open RAN environment.

AT&T made some waves when it first announced its open RAN push by relying on Ericsson as the underlying platform provider. McElfresh reiterated that the move made sense due to AT&T’s long-standing work with the Swedish vendor and its entrenched infrastructure presence.

The new radios will be running on Ericsson’s Intelligent Automation Platform (EIAP), which is the vendor’s service management and orchestration (SMO) platform. The EIAP will span across multiple domains, including the service level where it can control the cloud RAN and traditional RAN functions, the radios and the hardware.

McElfresh added that AT&T’s decision to go with Ericsson also propelled that vendor’s adoption of open RAN principles.

“We required them to open up their radio architecture, which up until the deal that we drove, they were somewhat unwilling to let some disruptive technology partners into the mix,” McElfresh said.

The willingness is important for Ericsson, which is seeing an increased share of its revenues coming from the North American market.

“North America continued to be very strong and grew by 55% year-over-year, driven by and helped by strong deliveries related to our recent AT&T contract win that’s now coming into delivery phase,” Ericsson CEO Börje Ekholm said during the vendor’s most recent earnings call.

Elkholm also stated that the vendor was seeing “selective network investments by other large customers.”

T-Mobile US is using Ericsson’s platform to power its recently launched 5G On Demand product, which the carrier is hawking as an easy way to deploy temporary private 5G services. Ericsson is also part of T-Mobile US’ AI-RAN Innovation Center that will be used to tie together cloud-based RAN and artificial intelligence (AI).

Ekholm also recently noted in an interview that the vendor was considering a move of its headquarters from Sweden to the United States due to increased opportunities.

Is open RAN gaining momentum? AT&T’s latest moves continue the operator’s decade-long open network narrative but is not unique as dozens of network operators have announced and moved on open RAN deployments.

Verizon, for instance, recently launched a multivendor open RAN distributed antenna system (DAS) at the University of Texas in Austin and the Austin Convention Center using equipment from Samsung and CommScope running on top of the carrier’s edge-focused virtualized cloud architecture.

Adam Koeppe, SVP of technology planning at Verizon, explained in an interview with SDxCentral that the deployment is the first of its kind and a key open RAN milestone.

“Having the ability to pick and choose vendors based on their capabilities and knowing that they can interoperate on either side of that equation and yield high performance, high quality, low cost, whatever your goal is, for the network,” Koeppe said. “In this case, you’ve got a Samsung component and you’ve got a CommScope component in the DAS system, so that hasn’t been done before. It represents, really, the true spirit, if you will, of [open] RAN where you have two vendors in that supplier system on either ends of that.”

Koeppe also touted Verizon’s level of announced open RAN detail and to the O-RAN Alliance specification tied to the deployment.

“Certainly, a very popular topic in the industry,” Koeppe said of open RAN, adding “not a lot of specificity coming out of operators in our industry related to actual O-RAN deployments.”

Verizon had previously announced it has deployed more than 130,000 open RAN “capable” radios that are compatible with specifications from the O-RAN Alliance. These radios include massive multiple-input, multiple-output (MIMO) antenna technology.

“Not just having one vendor with both the baseband and the radio being O-RAN compliant, but mixing and matching those and having a vendor for the baseband and a vendor for the radio, and they’re two separate vendors, that is really the most challenging aspect of O-RAN but it’s one that yields the most long-term benefit,” Koeppe added, though it should be noted that those comments were made before AT&T’s latest announcement.

Koeppe’s long-term view remains important for the open RAN ecosystem, which continues to flounder in the immediate term.

Dell’Oro Group recently reported that revenues related to the sale of open RAN equipment is set to plunge for all of 2024.

“Short-term projections have been revised downward, while the long-term outlook remains unchanged,” the firm noted. “Open RAN is now projected to comprise a mid-single-digit share of the 2024 RAN market and 8% to 10% of the combined proprietary plus open RAN 2025 revenues.”