Light Reading met with Sprint Corp. (NYSE: S)'s CTO John Saw and Glenn Laxdal, head of technology and strategy for Ericsson North America, at what was essentially a nerd tailgate party in a parking lot outside the stadium before the game began.
"This is one of the first 5G demonstrations at a large outdoor public event," Saw said. "There's no safety net."
The demo was running a 15GHz pre-standard 5G basestation mounted high on a truck nearby, feeding a large test terminal, which might moonlight as a riding mower on the weekend. The data rates shown usually ran from 3 Gbit/s to close to 4 Gbit/s. (Ericsson's Laxdal said that the system can achieve up to 5.5 Gbit/s in optimal conditions, but, hey, a test in the open air is usually a good proof-of-concept, right?)
The test used two 4-by-4 multiple input multiple output (MIMO) antennas, with "single beam" MIMO. This test was using a lot of spectrum, a 400MHz swathe of bandwidth, in fact. Typical 4G deployments might use a tenth of that today with channel bonding (carrier aggregation), or -- often -- much less.
The test was held over a closed-loop system with fiber delivering a live video stream to the basestation.
What's the frequency, John? The two stadium tests that Sprint has done so far utilized a 73GHz system from Nokia Networks and a 15GHz rig from Ericsson AB (Nasdaq: ERIC). The Sprint CTO says, however, that the operator's first 5G efforts will use its existing 2.5GHz spectrum. Sprint says it holds 160MHz of 2.5GHz spectrum in the top 100 US markets. (See Sprint Kicks Off 5G Tests in Levi's Stadium.)
"We're going to start with 2.5 because we can do a lot with 2.5," Saw says. (See Sprint CEO: Our Spectrum Is for 5G.)
Ericsson is now working to create a "massive MIMO" prototype for Sprint. This is aiming to combine 16-by-16 antenna arrays to create an overall 64-by-64 array. Ericsson's Laxdal hopes to have that in the labs this year and to tweak it in the field in 2017, with early applications -- think fixed wireless -- in 2018.
— Dan Jones, Mobile Editor, Light Reading