There has been some concern about the 3.5 GHz band since the industry started eyeing it for both licensed and unlicensed usage. In effect, that band is fraught with more issues than many of the other bands. For one, it is a part of the spectrum that is well understood and mature. There is little left to be learned about it.
It seems like a great niche for evolving 5G applications, as well as the Internet of Anything/Everything (IoX), autonomous vehicles and smart “X,” LTE, among other things.
This band has a number of military and satellite incumbents that were, at first, pretty nervous about opening up this band to 5G or other services because it could compromise the incumbents signal purity. However, that concern has be, generally, alleviated with the three tier model. But there is still some concern that has not fully been resolved.
Presently, the FCC is considering a three-tiered spectrum access system that protects incumbent users while opening up priority access and general access licenses. The major issues are, the length of licensure term and the geographic area associated with the license, as well as larger partial economic areas (PEAs). At a high-level, longer licensure terms and larger licensure areas would favor national mobile operators.
In this camp are carriers, vendors, web engines such as Google, and more. It is a pretty strong coalition of players that want to see this band open to both unlicensed and licensed platforms. The reason for that is because CBRS frequencies significantly lower the barrier to entry with its propagation characteristics. Additionally, the limited propagation characteristics of the band play well for indoor, floor-by-floor, deployment options that rival current WiFi networks.
The stakeholders wanting to use the 3.5 GHz CBRS band claim that the spectrum access system (SAS), developed by Google, Federated wireless, and some others, can be successfully implemented, thereby effectively using, and sharing, available spectrum without causing harm to incumbents. SAS would prioritize spectral access based on the level of access each type of license affords. And, there is a lot of pressure by them to get this moving. But there is trouble within this camp.
There is also pressure by the Industrial Internet of Things (IIoT) coalition. The coalition wants a piece of the action because, it claims that critical-infrastructure entities should have a reasonable opportunity to compete for, acquire and use CBRS spectrum. They want to self-provision private wireless networks that support robust IIoT applications and services. Their claim points to safety and security as the basis.
For example, the Wireless Internet Service Providers Association (WISPA) is not a fan of T-Mobile and CTIA asking for proposed 3.5 GHz rule changes, especially to try and eliminate general authorized access (GAA) channels. Other concerns include no longer being able to afford licenses if the changes large carriers are asking for are made.
Another issue comes from the Rural Wireless Association with its concerns over changes to priority access licenses (PALs). Specifically, the changes to the PAL licensing rules that allow longer license term with a renewal expectancy and larger geographic license areas. The concern is, that such changes would limit PAL spectrum access to all but the largest carriers, with the potential to warehouse spectrum as has been the case previously.
All of these are going to shake out this year and next. But there is one area where CBRS has yet to be worked though – 5G. Presently, there are no restrictions on using the 3.5 GHz band for 5G services as they emerge. So that presents quite an opportunity for the areas mentioned a bit earlier in this missive.
The 5G world is rapidly coming around to realizing that the propagation characteristics of CBRS are prime for certain 5G services (mobile, for example). As well, this band is more global than many, in terms of a worldwide platform for 5G services.
It will take another year or two of posturing by both the public and private sectors to get a clearer picture of exactly how this spectrum will shake out…stay tuned.
Executive Editor/Applied Wireless Technology
His 20-plus years of editorial experience includes being the Editorial Director of Wireless Design and Development and Fiber Optic Technology, the Editor of RF Design, the Technical Editor of Communications Magazine, Cellular Business, Global Communications and a Contributing Technical Editor to Mobile Radio Technology, Satellite Communications, as well as computer-related periodicals such as Windows NT. His technical writing practice client list includes RF Industries, GLOBALFOUNDRIES, Agilent Technologies, Advanced Linear Devices, Ceitec, SA, and others. Before becoming exclusive to publishing, he was a computer consultant and regularly taught courses and seminars in applications software, hardware technology, operating systems, and electronics. Ernest’s client list has included Lucent Technologies, Jones Intercable, Qwest, City and County of Denver, TCI, Sandia National Labs, Goldman Sachs, and other businesses. His credentials include a BS, Electronic Engineering Technology; A.A.S, Electronic Digital Technology. He has held a Colorado Post-Secondary/Adult teaching credential, member of IBM’s Software Developers Assistance Program and Independent Vendor League, a Microsoft Solutions Provider Partner, and a life member of the IEEE. He has been certified as an IBM Certified OS2 consultant and trainer; WordPerfect Corporation Developer/Consultant and Lotus Development Corporation Developer/Consultant. He was also a first-class FCC technician in the early days of radio. Ernest Worthman may be contacted at: firstname.lastname@example.org.