The FCC is getting set to vote next week on a proposal to free up spectrum for unlicensed use that could support gigabit Wi-Fi when combined with an adjacent spectrum band already used for Wi-Fi.
This would be the second spectrum band the FCC has freed up that could support gigabit Wi-Fi in just a few months, as we discussed with Alex Roytblat, vice president of worldwide regulatory affairs for industry organization Wi-Fi Alliance, in a phone interview.
The latest version of Wi-Fi standards, Wi-Fi 6, can support gigabit speeds, but how much speed a user gets depends, in large part, on the size of the channels used, Roytblat explained.
“Wi-Fi 6 is designed to operate on 20-,40-, 80- or 160-MHz channels,” he noted, and “to derive maximum benefits, they would need access to 160-MHz channels.” The 6 GHz band between 5.925 and 7.125 GHz, made available for unlicensed use back in April, is 1200-MHz wide, meaning that it can support seven 160-MHz channels.
The ability to support multiple 160-MHz channels will be “critical when you have a high-density user environment,” observed Roytblat.
The Upcoming Vote
The proposal that the FCC will vote on later this month involves 45 MHz of spectrum in the 5.9 GHz band which, alone, wouldn’t be sufficient to support 160-MHz channels, but which would be able to do so when combined with the adjacent UNII-3 band.
The UNII-3 band includes spectrum between 5.725-5.85 GHz, which has been in use with Wi-Fi for quite some time. The 45 MHz of spectrum in the 5.9 GHz band that the FCC will vote on lies between between 5.85 and 5.895 GHz and is sometimes referred to as the “lower 45 MHz” of the 5.9 GHz band.
Even just a single additional 160-MHz channel could help ensure there is sufficient bandwidth and capacity for gigabit Wi-Fi. And if the FCC approves the proposal for an unlicensed spectrum in the 5.9 GHz band later this month, that spectrum could be put to use for gigabit Wi-Fi quite quickly – for indoor use, at least.
Gigabit Wi-Fi Spectrum
The lower 45 MHz of spectrum in the 5.9 GHz band that the commission aims to make available for unlicensed use is currently used, on a sparse basis, for DSRC, a type of vehicular communications that has been largely obsoleted by more recent CV-2X technology.
As Roytblat explained, current DSRC users will have one year to move out of the spectrum band, and outdoor Wi-Fi use in the 5.9 GHz band won’t be feasible on a widespread basis until that happens.
In response to the COVID-19 pandemic, however, the FCC has granted special temporary authority to some wireless ISPs to use the lower 45 MHz of the 5.9 GHz for outdoor use in rural areas.
Indoor use of the 45 MHz of spectrum in the 5.9 GHz band could begin almost immediately after FCC approval, as equipment designed for indoor use operates at lower power levels and would not interfere with DSRC operations.
Some Wi-Fi equipment already deployed that operates in the UNII-3 band may be modified to use the lower 45 MHz of the 5.9 GHz band via a software upgrade, Roytblat noted.
There are no spectrum-clearing issues involved with the 6 GHz band. As with any unlicensed band, though, Wi-Fi users will need to share the band with other unlicensed users and must meet various interference mitigation and other requirements that manufacturers already have developed a range of technologies to address.
The Wi-Fi Alliance has given the name Wi-Fi 6e to a standard for gigabit Wi-Fi operating in the 6 GHz band and expects to certify equipment meeting that standard by early 2021, Roytblat said.
Projections from other organizations call for shipments of Wi-Fi 6e-enabled devices to exceed 200 million by 2021, he noted.
Moving forward, we might expect the industry to look at developing Wi-Fi standards with channels even wider than 160 MHz, and if so it might be useful to be able to combine spectrum in the 5.9 GHz band with spectrum in the 6 GHz band, but as Roytblat noted, that’s not currently an option, because the unlicensed spectrum in the two bands is not adjacent.
He added, however, that in the future “maybe some clever guys can do some amazing things.”