NFL coaches using private 3.5GHz CBRS network

In recent FCC filings, the National Football League (NFL) said it expects to continue using an in-stadium, coach-to-coach communications system running in the newly released 3.5GHz CBRS spectrum band.

The plan is noteworthy because the spectrum band is being used for critical, time-sensitive communications inside massive NFL football stadiums during games. Such environments can be extremely challenging for RF engineers to address.

Indeed, big wireless network operators like Verizon, AT&T and T-Mobile routinely spend millions of dollars building wireless networks inside football stadiums and other high-traffic venues. But those networks are shared among tens of thousands of users. The NFL's network, on the other hand, appears built specifically to make sure that coaches can communicate with each other during games.

A complex setup

The NFL's use of the CBRS band for coach-to-coach communications is covered by some of the league's recent filings with the FCC, the federal agency in charge of managing the nation's spectrum resources. The NFL first hinted at its interest in such a network in 2018 filings, as reported by FierceWireless, but the new documents indicate that those tests have evolved.

Specifically, the NFL mentioned its desire to "operate its in-stadium, coach-to-coach CBRS communications system," and said those systems are in all NFL stadiums.

Figure 1: (Source: Paula Smith/Alamy Stock Photo)

The filings also outline the NFL's efforts to maintain primary and backup Internet connections during games.

"The NFL uses a Lumen hardwired Internet connection at each NFL stadium, and Verizon LTE service as a backup Internet connection. The NFL uses a Cisco Meraki switching system at each stadium to provide automatic rollover from the Lumen connection to Verizon LTE in the event of a hardwired Lumen connection failure," the filing explains. "This level of redundancy has proven to be both necessary and sufficient to minimize the chances of an outage."

Verizon's involvement comes as little surprise, considering the company's extensive dealings with the NFL as a sponsor and technology partner.

The FCC opened the CBRS spectrum band to commercial operations starting in 2020. The band is unique in that it's shared among unlicensed and licensed users and the US Navy. Companies ranging from Helium to Dish Network to Comcast have pledged to build extensive mobile networks using the band.

JMA equipment

According to a source familiar with the NFL's operations, vendor JMA Wireless supplied some of the equipment for the NFL's CBRS coach-to-coach network. The vendor also helped design the network to prevent interference among coaches and interference between its network and other wireless networks in NFL stadiums.

Officials from JMA and the NFL either declined to comment on the situation or did not respond to requests for comment.

Wireless networks inside football stadiums have been a hot topic for years. For example, Verizon spent $119 million outfitting SoFi Stadium and the surrounding Hollywood Park area with its 5G network equipment for the Super Bowl LVI earlier this year.

Part of the reason football stadiums are a talking point for wireless network operators is simply due to the difficulties surrounding wireless networks inside such venues. Providing reliable broadband speeds via wireless technology to tens of thousands of football fans inside a stadium is an RF engineering feat thought virtually impossible just a few years ago.

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— Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano