With the 3.5GHz CBRS band now commercially available in the US -- after years of preparation -- we can look ahead to what happens next as the midband frequency is used for 4G, 5G and possibly more.

Federated Wireless CEO Iyad Tarazi is looking forward to 4G and private network usage of the CBRS band, and preparing to bring up the 5G specification for 3.5GHz later this year. Even further out is work to open up the 6GHz band in a similar manner to CBRS.

Initial stages of commercial service
But there's traction being made today. Tarazi told Light Reading that Federated Wireless has "35 customers in deployment right now." Those customers include Verizon Wireless, which is using the frequency for 4G network densification, and Charter Communications, which is offering fixed wireless in North Carolina using the band.

There are "100-plus cell sites going up a day," comments Tarazi.

The 150MHz of CBRS spectrum is today being used for unlicensed General Authorized Access (GAA) use cases. The FCC plans to auction 70MHz of spectrum in the 3.5GHz band for Priority Access Licenses (PALs) this June.

"All 150 [MHz] is available everywhere even after the PALs," explains Tarazi, adding that the GAA spectrum can still be used if a PAL spectrum license isn't being used in a given area.

5G on tap
CBRS is already on track to become part of the 5G specification. "We expect [5G] trials to start mid-year," said Tarazi. A 5G launch on the CBRS band is expected to happen in the first quarter of 2021.

NTIA spectrum plans
The National Telecommunications and Information Administration (NTIA) said at the end of January that it is considering repurposing the 3450MHz-3550MHz band for commercial services. The 3450-3550MHz band is adjacent to the CBRS band (3550MHz-3700MHz), and Tarazi expects the commercialization of that band to get underway by the end of next year.

There's a broad expectation that the 3450MHz-3550MHz band will "follow the same rules" as the CBRS band, Tarazi said. CBRS uses a shared spectrum scheme that gives top-tier spectrum continued access to incumbent government users while also paving the way to providing priority access to PAL license winners priority access along with the currently provided access to GAA, which today can use the full slice of 150MHz allotted in the 3.5GHz band.

Opening up 6GHz
Tarazi said one of Federated's next goals is to get involved in the opening up of the 6GHz band and potential sharing of that spectrum between WiFi, 5G and private lines for wireless communications. The FCC has proposed allowing unlicensed devices to operate in this band, which should open up the spectrum for WiFi 6 in 2020.

Tarazi has said that using a "6GHz automatic frequency controller" to manage spectrum in that band would open up the frequency to enable sharing between 5G, WiFi and municipal private lines in a similar way the CBRS band is now being used. He believes 70% of the 1200MHz spectrum in the 6GHz band could be freed up for WiFi and 5G use in the future.

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— Dan Jones, Mobile Editor, Light Reading