Gordon Mansfield of AT&T "told [management] that I want every day that’s left in the year ... The equipment is literally coming off production lines and going into the field — we are not even using normal shipping channels.” AT&T is the first in the world to use 39 GHz, a remarkable achievement.
AT&T has one of the best and most experienced senior engineering teams in the world, but the first efforts are struggling. It claims the supplier - probably Ericsson - isn't ready with the equipment in the 39 GHz band. They refuse to provide information on network speed. It may be as low as 250 megabits, half the LTE speed at T-Mobile in Manhattan.
“Now, in mmWave, it’s a new frontier. Sometimes you expect the signal to be there and it isn’t, so you have to adjust. As you move through the coverage area, you will be served by different beams, and you have to understand transitions between beams,” said Hristov. “RF engineers have to be hyper-accurate about placing and facing nodes … [because] if you don’t land on the right beam, you won’t get maximum performance.”
Mansfield also said, "The first IoT devices will be really high-end." Most users will "trade off capability for cost.” said Mansfield, noting that the first 5G IoT devices will be “really high-end.” I believe almost everyone will continue to use Bluetooth, Wi-Fi and 4G for IoT for years. 5G units will not just be expensive. They will be large and run down the battery.
Todd Zeiler confirms that mmWave and sub-6 are very different. "We need to explain that we have a fork in the road now. Millimeter wave will have a similar improvement, but sub-6 is about a more efficient interface with improved latency — it’s not about speed-doubling." 3GPP did the world a disservice by calling both 5G.
The AT&T folks agree there's a long way to go. Hristov notes, “It will take years to get to the point where you have the right tooling to accurately predict what you are trying to cover and serve," Zeiler adds, "software upgrades in 2019 that enhance beam-forming capabilities not expected to be mature until sometime in 2020."
The good news: "Coverage and data rates have generally been better than expected."
Quotes from 5G Networks Under Construction by Rick Merritt of EE Times.