An Evaluation of AT&T Millimeter Wave Markets March 5, 2019 12:00
This morning, Light Reading published an article on AT&T and Verizon's 5G mmWave deployments. In the article AT&T's SVP of wireless technology, Igal Elbaz, indicated that AT&T is initially deploying 100 MHz channels from their 39 GHz spectrum. I decided to look at their initial deployment markets to see how this was accomplished. One of the challenges that AT&T faces, is the fact that the 39 GHz band is in a bit of transition. It currently consists of 14 (50 MHz each) paired channels, but after the 37 and 39 GHz auctions, it will be reconfigured into 14 TDD channels (100 MHz each). For AT&T to be able to launch a 100 MHz channel in the 39 GHz band, they would need to control 3 contiguous channels so they can create a guard band on each side of their commercial channel. This is necessary because they are operating a Timing Division Duplex (TDD) channel likely in the 39 GHz downlink band. TDD means that the channel transmits and receives in the same band or channel. Without the guard bands AT&T 5G channel would be subject to interference especially when the channel is receiving data from mobiles.
So now let's take a look at AT&T's spectrum ownership using Allnet Insights' Millimeter Wave - Spectrum Ownership Analysis Tool (Spectrum Grid).
In Louisville, AT&T controls 4 contiguous channels in the downlink band (5-B, 6-B, 7-B, and 8-B) They can use 6-B and 7-B for their 5G channel and 5-B and 8-B for the guard bands. In the article Igal indicated that AT&T would expand to 4 - 100 MHz channels in the future. That will not be during 2019 and likely not during the first half of 2020.
In Louisville, AT&T already controls the necessary 400 MHz of spectrum but AT&T will need to wait until the 37 and 39 GHz auction are complete to "repack" their 39 GHz spectrum into the new band plan below along with the auction winners to get their remaining spectrum "deployable".
Oklahoma City, OK:
In Oklahoma City AT&T only controls 3 contiguous channels (8-B, 9-B, and 10-B). I would expect that AT&T has centered its 5G channel on channel 9-B and it using 25 MHz of 8-B and 25 MHz of 10-B for guard bands.
The final market we will look at is Dallas. It is apparent that AT&T lacks the required 3 contiguous channels necessary for a 100 MHz 5G channel in this market. As you can see, the FCC controls the 13-B and 14-B channels adjacent to AT&T's 12-B and 13-B channels. I believe that AT&T has likely requested Special Temporary Authority (STA) from the FCC to use these channels until they are auctioned.