The industry is abuzz about the advantages of 5G private networks, for use in industrial IoT, augmented and virtual reality (AR & VR) applications and machine-learning robots. The delivery of private 5G networks, however, is still several years away.

Meanwhile, 150MHz of Citizens Band Radio Service (CBRS) spectrum is finally starting to come online at the end of 2019. The FCC is first opening up the unlicensed spectrum in the 3.5GHz band, with a Priority Access License (PAL) auction to follow on June 25 next year.

Google, Federated Wireless, CommScope, Amdocs and Sony had their Spectrum Access Systems (SAS) approved in mid-September and these companies were allowed to start small, limited-time initial commercial deployments (ICD).

The SAS allows dynamic sharing of the CBRS spectrum between three classes of users. Tier 1 is government (naval coastal radar) and fixed satellite users. Tier 2 users will be the winners of the 70MHz PAL spectrum auction, who must protect incumbent Tier 1 users from harmful interference. Tier 3 users are General Authorized Access (GAA) users, who must protect both Tier 1 and Tier 2 users from interference to use their 80MHz of midband spectrum.

Final commercial deployment (FCD) by initial Tier 3 GAA users will start at the end of this year.

"CBRS has been a long time coming," comments Joel Lindholm, VP of Ruckus LTE Business at CommScope. The FCC initially started to set up rules for the commercial use of the 3.5GHz band in 2012.

Mobile network operators, such as Verizon, and cable providers, like Charter, are already testing CBRS. Charter has said that it is testing an indoor campus private network near its offices in Denver. The cable provider says that it has used 100 fixed transmitters and 500 fixed and mobile user devices in the test at its offices.

It is estimated that there are around 40 different types of devices available so far supporting the CBRS band. CommScope's Lindholm noted that Apple's recently released iPhone 11 smartphone now supports the 3.5GHz frequency.

Lindholm says that CommScope's SAS allows it to provision spectrum for use in a private network fast. "We can put a network inside of a building very quickly," Lindholm claims. CommScope has already tested a private LTE network at a racetrack in Phoenix, Ariz., back in November 2018, among other trials of the midband LTE technology.

The end of 2019 will signal the start of the arrival of commercial CBRS 4G networks in the US. Lindholm notes that 5G will be supported on the 3.5GHz band in the US too. "We absolutely intend to support 5G on the CBRS band," he states.

Still, Lindholm feels that private 5G networks remain distant at present because 3GPP Release 16 specifications like network slicing, which will let operators provide sections of their 5G network for dedicated uses, haven't even been released yet. Initial unlicensed 5G spectrum (NR-U) is also part of the Release 16 bill of goods.

Release 16 (aka 5G Phase II) is due to be completed in June 2020. It will be some time between the completion of the spec and a commercial rollout of Release 16 features on a network. This will all come into play vis-à-vis private networks, particularly as many enterprises are not keen to be on the cutting edge of network technology.

"I'd say it's a few years out yet," Lindholm says of potential private 5G networks.

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— Dan Jones, Mobile Editor, Light Reading