A key component to sharing in this band is the Spectrum Access System (SAS), which utilizes database technology to protect important federal government uses of spectrum. These systems will ensure that neither priority access nor general authorized access users interfere with the existing government and private users who will continue to need 3.5 GHz spectrum in a limited number of areas. SAS database systems also will allow new users to share effectively with each other. Google has been a leader in using databases to free-up available spectrum, and it is one of the companies working to develop a sharing system for the 3.5 GHz band.
There’s been a lot of breathless excitement regarding Google’s wireless test plans, mostly the result of eternal hope that magic radios will appear one day and render wireline technology obsolete. That hope is stoked by AT&T, which wants permission to replace rural and inner city copper with wireless systems, and other mobile broadband companies that, naturally, want those customers too.
There aren’t many details in the heavily redacted filing and it offers no reason to think Google is on the verge of a radical breakthrough in fundamental physics or radio technology. There’s also nothing that says they aren’t, so we might as well have some fun speculating.
But Google has another, perfectly good business reason for running its wireless tests. Real time frequency coordination will open up new spectrum and increase the bandwidth that can be pushed through existing allocations, making it a potentially lucrative service that can be sold to wireless operators, and put Google at the center of wireless network management and the data streams that go along with it.
More unlicensed spectrum for WiFi and other uses will add value to the U.S. economy. That’s the argument FCC commissioner Jessica Rosenworcel is making to congress as a matter of general policy and to colleagues as opportunities to reallocate frequency assignments are evaluated.
That argument is nonsense, for three reasons. First, current plans call for retaining a smaller slice for public safety-related transportation purposes. Second, even that isn’t necessary since automakers will still be able to use the entire band, albeit on a shared basis. Third, and most importantly, the wireless ecosystem is far more complex and interdependent than it was 20 years ago. By way of example, Qualcomm recently released specs for its connected car reference platform which will support a mind-numbing array of wireless and networking technologies…
…including Qualcomm® Snapdragon™ X12 and X5 LTE modems, quad-constellation Global Navigation Satellite System (GNSS) and 2D/3D Dead Reckoning (DR) location solutions, Qualcomm® VIVE™ Wi-Fi® technology, Dedicated Short Range Communications (DSRC) for V2X, Bluetooth®, Bluetooth® Low Energy and broadcast capabilities such as analog and digital tuner support using software-defined radio via Qualcomm® tuneX™ chips. In addition, the platform features in-vehicle networking technologies such as Gigabit (OABR) Ethernet with Automotive Audio Bus (A2B) and Controller Area Network (CAN) interfaces.
Translation: nobody needs another obsolete-on-release proprietary wireless technology from carmakers. The sooner this 75 MHz is repurposed, the better for everyone.
Kind of like parking one of these in a yacht harbor. But it’s OK. They’ll be careful.
With the rate of growth – let alone growth itself – in mobile data usage continuing to boom, with no end in sight, mobile carriers are searching for new spectrum. First choice is licensed, exclusive frequencies of course, but there’s no reason for them not to grab for their second choice too, which is unlicensed spectrum.
As you might expect, the people on the carrier side of the business think it’s a great idea for carrier-class LTE-based services to jump in alongside WiFi, particularly in the 5 GHz bands. Those on the WiFi side of the divide, including Google and Broadcom, think there needs to be formal coordination between the two camps before any sharing schemes move further…
The Wi-Fi Alliance is not at all convinced that [unlicensed LTE technologies] are going to play fair with Wi-Fi. According to the alliance, there is insufficient information about how [unlicensed LTE technologies] will coexist with Wi-Fi and other users of unlicensed spectrum. While efforts are underway to foster collaboration between the affected parties, it urges the commission to continue monitoring developments to ensure there is sufficient dialogue and consideration on how unlicensed spectrum will be shared fairly…
[Unlicensed LTE] is a proprietary system developed privately by a few companies, and it employs carrier sensing adaptive transmission (CSAT) technology that is not under consideration by [the LTE standard group]. “This lack of industry standard implementation of CSAT means that its impact on other users of shared spectrum will be variable and unpredictable.”
I don’t doubt that whether or not it’s coordinated, there is a lot of effort going into trying to minimise the damage mobile carriers do to unlicensed users, including wireless Internet service providers. But even if optimally designed, adding countless access points professionally engineered for maximum effectiveness to unlicensed bands will significantly raise the RF noise floor and make it more difficult for independent operators to provide wide area service. The impact on hotspots and home routers might be minimal, but don’t assume the same will be true for WISPs.
The U.S. defense department is giving up its sole control 100 MHz of prime spectrum – 3550-3650 MHz – which is adjacent to 50 MHz – 3650-3700 MHz – that’s already available for semi-licensed use, and the Federal Communications Commission is combining it all into a new citizens broadband radio service that will share the space with existing users. An automated spectrum access system (SAS) will coordinate use by three different classes of users with different levels of privileges. Existing users come first, followed by two new classes…
The Citizens Broadband Radio Service itself consists of two tiers—Priority Access and General Authorized Access (GAA)—both authorized in any given location and frequency by an SAS. As the name suggests, Priority Access operations receive protection from GAA operations. Priority Access Licenses (PALs), defined as an authorization to use a 10 megahertz channel in a single census tract for three years, will be assigned in up to 70 megahertz of the 3550-3650 MHz portion of the band. GAA use will be allowed, by rule, throughout the 150 megahertz band. GAA users will receive no interference protection from other Citizens Broadband Radio Service users.
The military will still operate in the band and as an incumbent user will have top priority over civilian broadband systems, but that’s only where there’s an actual, as opposed to a vaguely theoretical, conflict. The 3650 band has long been used on a lightly licensed basis by commercial broadband companies that have to coordinate use with grandfathered C-band satellite ground stations. Taking it to the next level by tripling the amount of available spectrum and automating the coordination process is a huge step forward.0