It might not rank up there with the introduction of the iPhone or the launch of 4G LTE., but yesterday marked an important day in the history of wireless services, with the launch of Commercial Deployment Citizens Broadband Radio Services (CBRS). This has been years in the making, and is testament to a combination of innovation, persistence, and a level of public-private cooperation that we probably all wish was more prevalent. I’d like to use this column to explain why CBRS is significant, how it will used, and what the roadmap looks like for the next couple of years.
CBRS utilize 150 MHz of spectrum in the 3.5 GHz band, so it’s sort of ‘mid-bandy’. Half of the spectrum will be made immediately available in what is known as the ‘General Authorized Access’ (GAA) layer. In GAA, the spectrum is unlicensed, similar to Wi-Fi. Companies — mainly service providers, but also venue operators and enterprises who are certified — can request to use a certain number of channels for a specified amount of time and in a certain area. This ‘spectrum sharing’ database will be administered by one of five companies who have been chosen by the FCC to be Spectrum Access Systems (SAS) Administrators: Federated Wireless, Google, CommScope, Amdocs, and Sony. Any customer that wants to use CBRS must sign up with one of the SASs.
Although CBRS is launching later than originally planned, it is important to step back and acknowledge getting to this point marks a significant accomplishment. The genesis of CBRS goes back to 2012, when the President’s Council of Advisors on Science and Technology (PCAST) released a report, “Realizing the Full Potential of Government-Held Spectrum to Spur Economic Growth”. This report envisioned the need to provide a framework for spectrum sharing. This means that the spectrum would not be owned by any one entity, or auctioned off in the manner that has been prevalent since the mid-1990s. So, the idea was hatched to use the 3.5 GHz band, which has been historically (but sparingly) used by the U.S. federal government, principally the Dept. of Defense. Notably, 3.5 GHz is being adopted for 5G in China and other parts of the world. The FCC, and key participants across the service provider, vendor, and public sector ecosystem developed the idea to create the SASs. And in order to allow the military and other government agencies to continue to use the spectrum, the SASs would also operate an Environmental Sensor Network, which is equipment installed to detect the presence of federal incumbent radar transmissions in the 3550-3650 MHz portion of the 3.5 GHz band.
Over the past few months, the SASs have been certified and the ESCs have been tested. The CBRS Alliance, which consists of key players across the ecosystem, has branded CBRS services as OnGo, which pertains to LTE in the CBRS spectrum. A special event was held in Washington, D.C. on Wednesday, where key participants in the development of CBRS were acknowledged, and some of the Initial Commercial Deployments (ICDs) were announced. The ICDs must run for a minimum of 30 days, after which the SAS Administrators must file a report on their experiences.
OK!! So how will CBRS be used and what is the significance? It should be noted that CBRS is best suited to small cells and in-building type deployments as there are limitations on the power output of the equipment. The use cases depend, to a certain extent on the service provider. The incumbent mobile operators will use CBRS to augment LTE speed and capacity. The spectrum will be incorporated into ‘Carrier Aggregation’ techniques that combine channels across a service provider’s spectrum holdings. AT&T and Verizon, particularly, have been equipping their cell sites (especially small cells) with 3.5 GHz radios to support CBRS. And, in a boost to CBRS, the iPhone 11, which becomes available on September 20, supports CBRS (Band 48), as does the Samsung Galaxy 10, select other high-end smartphones, and a number of other devices such as mobile hotspots.
CBRS could also be very useful for cable companies, who could augment their hybrid MVNO/Wi-Fi hotspot based wireless service with 3.5 GHz services in select cities. Wireless Internet Service Providers (WISPs), which operate fixed wireless networks in mainly rural areas, could augment their services using CBRS.
I also see venues, such as stadiums and convention centers, as likely early adopters of CBRS. These are the types of entities that need the significant, but temporary, boost in capacity that the CBRS framework is made for. There has also been a lot of discussion about enterprises using CBRS to deploy a private LTE network. Initially, they’re likely to do so in conjunction with service provider partners, but eventually, companies could obtain licenses to operate CBRS themselves.
If this initial wave of CBRS is successful, a compelling roadmap lies ahead. The FCC has set a goal for making the other half of the 3.5 GHz spectrum available through an auction of what’s called Priority Access License (PAL) in June, 2020. PAL will allow for longer license terms, larger coverage areas, some expectation of license renewal, and the ability for an owner to make some of its spectrum available on the secondary market. We also expect that the 3.5 GHz spectrum could be upgraded to 5G, although that is unlikely for at least a few years. Truth be told, CBRS is yet another tool in the toolbox that enables a service provider to improve the LTE experience to the extent that it looks like 5G–. Finally, if CBRS is proven successful, it’s envisioned that some future 5G millimeter wave (mmWave) bands might be designated for spectrum sharing.
Finally, at this notable moment in the history of wireless, congratulations are in order to some of the key players who had the vision and persistence to make CBRS a reality: FCC Chairman Tom Wheeler (and current Chairman Ajit Pai who saw it through); Iyad Tarazi, CEO of Federated Wireless, one of the few startups in the game; and the 150-member CBRS Alliance, which developed specifications, helped negotiate the choppy waters of the GAA and PAL license schemes, developed numerous case studies, and developed the OnGo brand and certification program; and numerous vendors who played an instrumental role in evangelizing CBRS and then developing solutions including Google, Ericsson, Boingo, Commscope (which owns Comsearch and Ruckus Wireless).
And with all the negative stuff going on in Washington and with Big Tech, it’s nice to have this positive and optimistic moment, where the public and private sectors came together to make something happen. Companies who are also competitors worked together on the CBRS Alliance and with the FCC, DOD, and the NTIA to develop specifications and work out tough issues regarding license terms. This is also a moment of U.S. technology leadership. The concept of a spectrum sharing regime, and some of the technology used to develop and implement it, is a model that’s already being considered in several other countries.
