FAQ: What in the wireless world is CBRS?

FAQ: What in the wireless world is CBRS?

Explainer on the Citizens Broadband Radio Service (CBRS) shared spectrum in the 3.5 GHz band



First off, CBRS is an acronym for Citizens Broadband Radio Service, and the upshot for enterprise IT pros is that it could result in improved LTE services from service providers as well as enable enterprises to build their own private LTE networks (See also: "The big CBRS promise: Private LTE networks"). Here’s a primer on CBRS — because you are going to want to know about this.

Citizens Band/CB, as in CB radio?

No, good buddy, this has nothing to do with the Citizens’ Band radio service used by truckers for two-way voice communications and that lives in the 27 MHz spectrum band in the U.S.  CBRS lives in the 3.5 GHz band.

How did the 3.5 GHz band suddenly become available for new commercial services? Isn’t spectrum a super scarce resource?

The freeing up of the 3550-3700 MHz band stems from the 2010 National Broadband Plan issued by the FCC, which set out to make 500 MHz of additional spectrum available for new mobile uses. The FCC zeroed in on the 3.5 GHz band in rules issued in April of 2015, then reaffirmed those rules about a year later.

Aren’t the previous users of this spectrum band bummed out now? 

They’ll deal with it. A portion of the 150 MHz of spectrum in question has been used by the U.S. Navy, satellite service providers and utilities, but protections have been built into the CBRS rules to safeguard this Incumbent class of spectrum users. Spectrum Access System (known as SAS) and Environmental Sensing Capability services must be implemented to avoid any possible interference between users. Other classes of users are being designated Priority Access and General Authorized Access, the former of which will gain this privilege via a spectrum license auction for Priority Access Licenses (PALs) expected to take place either in 2018 or 2019.

So who’s going to use this spectrum?

Carriers look forward to extending coverage and capacity of their LTE services via the 3.5 GHz band. As we know from their efforts to horn in on the 5 GHz band used for Wi-Fi via a technology called LTE-U, carriers seek access to more spectrum. But cable operators looking to get into wireless also want in on this action, as will assorted managed service providers, which could include building management companies. What’s more, enterprises could use the spectrum to set up their own LTE networks, including to support internet of things devices. LTE services in the 3.5 GHz band will work indoors and outdoors.

What sort of applications will CBRS be used for?

Service providers are expected to use CBRS to replace last-mile fiber access, deliver fixed wireless services and even point-to-multipoint offerings. Enterprises and managed service providers could exploit the 3.5 GHz band for IoT connectivity and even for Wi-Fi replacement or supplementary services. LTE services could hit 1Gbps indoors and maybe 5 or 10 times that for outdoor uses with line-of-sight access. CBRS backers say the economics of this technology are much better than those of distributed antenna systems and they contend the speed and consistency of service will be much better than Wi-Fi. CBRS supporters also say imaginative new services will be enabled by availability of more cheap spectrum: Nokia, Qualcomm and Google parent Alphabet’s Access group recently demoed a private LTE network over CBRS at Las Vegas Motor Speedway designed to give fans a 360-degree virtual reality view into speeding race cars in real time. 

Where will software, equipment and services come from to support all this?

Here’s one clue: Almost 40 vendors, from the Big 4 carriers to service provider equipment vendors Ericsson and Nokia to enterprise equipment companies like Cisco and Ruckus to chipmakers like Intel and Qualcomm have banded together in the CBRS Alliance. Look for smartphone and computer makers to join too, once carriers make their requirements clear. Samsung already belongs to the CBRS Alliance. Apple? “Apple will follow the market. Apple will get here,” says Iyad Tarazi, CEO of CBRS Alliance founding member Federated Wireless. “We’ve been careful at this point not to focus on the handset makers because that relationship is typically owned by the carriers. What we have focused on is making sure the chipsets and modems and all of the capabilities are coming this way.”

What’s the timeframe for CBRS from here?

The FCC has doled out licenses for vendors to conduct CBRS trials, and some of these companies showed off their wares at Mobile World Congress in Barcelona earlier in 2017. The FCC is expected to begin certifying equipment later this year, working with the Wireless Innovation Forum, and the CBRS Alliance later also hopes to begin certifying service providers before long. So expect rollouts by the second half of 2017. 

Will changes in the FCC’s leadership have any impact on CBRS?

While the FCC under new Chairman Ajit Pai has embarked on a course to undo data privacy, net neutrality and other rules put into effect during the Obama administration, CBRS supporters claim they feel comfortable that the commission will not mess with CBRS to any large degree. Pai and fellow Republican FCC member Michael O’Rielly both initially voiced concerns about the 3.5 GHz shared spectrum rules, though did go along with the eventual plan as part of a unanimous ruling. The fact that the FCC did recently give the go-ahead to cellular base stations from Nokia and Ericsson for use in LTE-U networks, indicates support for shared spectrum endeavors. There could be tweaks forthcoming to the Priority Access License plans though.

What's all this mean for 5G wireless?

While the initial talk about CBRS focuses on 4G LTE services, there are no restrictions on using the 3.5 GHz band for 5G services as they emerge. In fact, it's quite likely that the band will be used for 5G, and that might synch nicely with services offered in other countries that are actually targeting the band for 5G services. What's more, the 3rd Generation Partnership Project (3GPP) is making moves to enable 5G radios to work in shared spectrum environments.

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