- Signals Research Group (SRG) conducted drive tests in the Dallas area on AT&T’s open RAN network
- Tests measured how 1Finity small cells interact with Ericsson small cells and macro gear
- AT&T identified locations where it had small cells and provided that to SRG but had no influence over where or how SRG tested
AT&T’s open RAN strategy got a lot of flak when it awarded Ericsson a $14 billion contract to overhaul its network in 2023. The pushback went something like this: Is it really open RAN if it’s being provided by a single provider, the very construct the open RAN movement was trying to get away from?
In part to answer that very question, Signals Research Group (SRG) CEO Mike Thelander recently conducted third-party tests on AT&T’s open RAN network in AT&T’s hometown of Dallas. The tests were conducted in March using an unlocked Galaxy S23 smartphone.
Here’s what he discovered: “If it looks like Open RAN, smells like Open RAN, and tastes like Open RAN, then it must be Open RAN,” he wrote on LinkedIn.
AT&T provided Thelander with the locations and physical cell identifiers (PCIs) of 1Finity and Ericsson small cells, as well as PCIs for Ericsson macro sites in the Dallas neighborhood of Deep Ellum.
He used this information to map out the test areas where he wanted to drive and capture the performance data on AT&T’s network. AT&T provided some logistical support when SRG collected the data, but otherwise wasn’t involved with the tests, according to Thelander.
Ericsson DU, 1Finity RUs
Seeing as how Ericsson isn’t known for loving open RAN (despite what Ericsson executives say), demonstrating that Ericsson is actually supporting a third-party radio was first and foremost the purpose of the tests, Thelander told Fierce.
“That was kind of the gist of it. See if it’s real and then see how it performs,” he said.
The upshot: Ericsson’s distributed unit (DU) works with 1Finity’s small cell radio units (RUs), demonstrating that Ericsson is, indeed, playing nice with a third-party radio vendor.
Thelander said he can’t say the equipment from Ericsson and 1Finity officially checked “every single box” on the open RAN compliance checklist.
“I have no way of knowing that. I just know that it’s a 1Finity RU and Ericsson DU. Is it going to work if you stick in another third party? I don’t know. I imagine with any deployment, there’s testing to make sure a different RU would work from a different vendor,” he said.
Geek out on small cells
Thelander did a fun “one of these is not like the other” post on LinkedIn after capturing some images of small cells on utility poles during his Dallas tests. He posted four images of small cells and asked readers to guess which of the four was Ericsson’s.
“They all look the same,” he said. “Because I had the cell ID information, I knew what cell was what.” He used that compare uplink and downlink performance, as well as a host of other data to compile his report.
Thelander’s tests weren’t isolated to the great outdoors – apparently he was thorough about the assignment. “We even tested inside a neighborhood pub so that we could justify watching a March Madness basketball game,” the SRG report says.
The next big thing is where these types of open RAN small cell deployments will show up next. Thelander said he’s aware of at least two major markets where AT&T will be significantly expanding its small cell network later this year, but he was mum on which ones.
Fierce asked AT&T and will update this article if they feel like sharing.