AT&T is commercially operating an open RAN network design in Dallas with equipment from Samsung and Ericsson, according to evidence uncovered by Signals Research Group.
The action is important because it indicates that open RAN technology has matured to the point that AT&T one of the world's leading 5G providers can run it in a commercial environment with equipment from two of the market's biggest network equipment suppliers.
However, AT&T isn't yet ready to talk openly about its open RAN efforts.
"We won't really have anything to contribute here," a spokesperson wrote in response to questions from Light Reading on the topic.
And, not surprisingly, the two vendors involved in the effort had little to add.
"Samsung is a leader in the Open RAN community and has been announced as one of AT&T's 5G suppliers. It is our policy not to comment on a carrier's network plans. Please contact AT&T PR for questions on their network specifics," wrote a Samsung representative in response to questions from Light Reading.
Ericsson representatives similarly referred questions on the topic to AT&T.
Details on AT&T's open RAN efforts come from Mike Thelander and Emil Olbrich of Signals Research Group. The firm conducted a number of network tests in Dallas, AT&T's headquarters, including on a handful of AT&T sites running equipment from Samsung and Ericsson.
"It was encouraging to witness an open RAN deployment within the continental United States," the firm wrote in a recent report, explaining that AT&T has deployed a Samsung millimeter wave radio at a few sites around downtown Dallas that connected to an Ericsson baseband unit.
Thelander explained to Light Reading that the firm wasn't able to confirm the exact interface being used between the Samsung radio and the Ericsson baseband. He said the interface could use the official standard from the O-RAN Alliance or merely reflect a vendor opening up the CPRI interface. The Common Public Radio Interface (CPRI) standard is the connection between radios and radio control elements.
Regardless, "it is more relevant that AT&T is pushing its vendors to support a multi-vendor 5G NR network than whether they are compliant with a published O-RAN Alliance interface," he said. "At least they're trying."
And how did AT&T's open RAN sites perform? "Performance could be better," Thelander acknowledged. "AT&T brought two vendors to the dance floor, but they have to figure out how to tango."
Nonetheless, the fact that Samsung and Ericsson agreed to connect their equipment in a multi-vendor environment for a major, incumbent wireless network operator is an important development in the industry. That's because open RAN technology has rapidly evolved from an obscure networking specification to a white-hot industry trend that is increasingly aligning with the geopolitical battle between the US and China.
Indeed, the US telecoms regulator is hosting an open RAN event next month featuring a keynote appearance by the US secretary of state.
At its heart, open RAN promises to allow operators to mix and match technologies from different vendors. That's a significant change from the current status quo, wherein one vendor supplies all of the equipment tightly integrated from the baseband to the radio for a given coverage area.
Operators have touted several benefits to open RAN. Perhaps the most noteworthy is that the technology would allow operators to more easily pit vendors against each other, potentially lowering prices. But open RAN technology could also open the industry up to new, specialist vendors, as well as allow operators to swap out networking components more easily, among other benefits.
Not surprisingly, some established vendors like Huawei and Ericsson have taken a hesitant approach to open RAN after all, it would dramatically upend their existing business models. Meanwhile, upstart vendors looking for an advantage such as NEC, Fujitsu and Samsung have voiced support for the technology.
AT&T isn't the only major wireless network operator that is moving forward with open RAN. Executives from Verizon have also said the operator is testing the technology, while Vodafone has said it could implement the technology across fully 100,000 sites.