Several new developments in TV White Spaces (TVWS) technology appear to have pushed the long-suffering sector forward. But problems -- namely interference worries by hospitals in the US -- continue to dog the market.

On the bright side, the FCC this week issued new rules for wireless operations in TV White Space spectrum. The rules are aimed at addressing a variety of technical concerns, such as how to locate TVWS devices.

And, separately, the WhiteSpace Alliance (WSA) and the IEEE Standards Association (IEEE-SA) inked a new agreement to speed the development of low-cost broadband services in the spectrum. "TV White Space holds particular promise for connecting currently underserved consumers at price points appropriate for large rural and remote populations, a solution sometimes referred to as 'Frugal 5G,' " the groups wrote in a press release. "WSA and IEEE-SA are currently defining several activities with relevant stakeholders from developing countries on projects that will involve spectrum sharing for applications such as rural broadband, e-commerce, e-health, smart cities and smart grid."

But, perhaps most importantly, the National Association of Broadcasters and TVWS proponent Microsoft appear to have reached a tentative agreement on additional rules for operations in the spectrum. "For the past several months, the National Association of Broadcasters (NAB) and Microsoft have been engaged in productive discussions regarding potential modifications to the Commission's television white spaces (TVWS) rules to facilitate operations in rural areas while ensuring that licensed operations are protected," the NAB wrote in a letter this week to the FCC. "As a result of these conversations, NAB agrees that the Commission should pursue certain, but not all, changes Microsoft is seeking, as long as the Commission takes important steps to protect licensed users."

The NAB specifically said it agreed with many of the technical solutions to TVWS problems that Microsoft originally proposed to the FCC in October.

The NAB's acceptance of some Microsoft's TVWS suggestions signals a bit of a détente between the two organizations. NAB has long complained about operations in TVWS, while Microsoft's AirBand program has been working for years to create an equipment ecosystem for operations in TV White Space spectrum.

Although the FCC would still need to make a final ruling on any agreement between the NAB and Microsoft, the NAB's letter on the topic nonetheless signals movement forward for TVWS. "We appreciate the discussions and collaboration with NAB over the past months that have led to this point, and echo their call to the FCC to move forward with key TV white spaces issues to close the broadband gap," added Microsoft in its own statement on the letter.

A long and complex history
TV White Spaces are basically slices of spectrum between analog TV channels, mainly in the 700MHz and 600MHz bands. The FCC first voted to allow unlicensed operations in TVWS in 2010, and Google's founder at the time hailed the move as the creation of "WiFi on steroids."

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But the TVWS sector hasn't panned out as proponents had expected. NAB and others have complained bitterly of deep flaws in the FCC's rules around operations in TVWS. That situation has largely prevented WiFi chipmakers from adding TVWS bands into their devices.

Microsoft got involved in 2017 with its AirBand initiative, which is generally geared toward creating a market for fixed wireless services in TVWS spectrum in rural areas. Over the intervening years, Microsoft has supported the launch of more than a dozen providers using TVWS spectrum to offer fixed wireless Internet services in rural areas around the country. Microsoft's goal is to use the program to connect up to 2 million rural Americans to the Internet by 2022.

And Microsoft now has another new, major supporter for TVWS. Rise Broadband, widely considered the largest privately held fixed wireless provider in the US with around 150,000 customers, said it is in the midst of launching its first TVWS operations.

"Thanks to Microsoft for injecting some life into the TV White Space equipment ecosystem," said Rise Broadband's Jeff Kohler. "All of the testing that we've done in the field and that we've done in the lab shows that we're going to be able to deliver well in excess of the FCC-mandated broadband speed of 25Mbit/s [downlink] / 3Mbit/s [uplink]. We'll be able to do it at good distances and with much better propagation than any other spectrum tool that we have in the bag right now being installed in low band."

Kohler described fixed wireless operations in TVWS spectrum as a good solution for hilly locations with lots of trees and other foliage, which can impair wireless transmissions. "We plan on using quite a bit of it this year," he said, though he declined to name the vendors Rise is using for TVWS transmissions.

So why is Rise using TVWS now? "The equipment was very expensive, the speeds were very slow, the technology was far behind," Kohler said of previous TVWS offerings. "It's too early to tell, but it looks like we're seeing a lot of advancement in that space right now. That's a new tool in the bag for us when we really need a sub-1GHz solution for line-of-sight reasons and terrain reasons and foliage reasons."

But problems remain
Although there's clearly newfound momentum in the TVWS sector, Michael Calabrese with the New America association cautioned that concerns remain. He said companies that supply wireless medical telemetry services to hospitals using Channel 37 of the TV White Space band continue to worry about interference to their operations from fixed wireless providers and others using TVWS spectrum.

The FCC, for its part, said in its recent order that "we will address at a later time those petitions addressing push notifications and white space device operation on Channel 37."

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