Assuming everything goes according to plans announced on March 27, the Federal Communications Commission will create a new wireless data service that’s intended for what Chairman Tom Wheeler calls “innovative uses” by consumers, carriers and data services.
The designated wireless spectrum is located in the 3.5 GHz band, basically halfway between the 2.4 and 5 GHz WiFi bands. Apparently because of the open-ended nature of the proposed use, the new service will be called the Citizens Broadband Radio Service.
The FCC staffers handling the press briefing shortly before the release of the Notice of Proposed Rulemaking couldn’t resist the temptation to sprinkle their discussion with CB lingo, answering some questions with things like “10-4.” While it wasn’t clear that the new data service would perpetuate the lawless nature of its analog namesake, there are some similarities.
The new band is designed to support activities including small cell deployments, fixed wireless broadband services and something the FCC calls general consumer use. As is the case with CB radio, the licensing requirements are attached to the FCC-approved communications equipment, meaning that there’s no requirement for individual users to obtain licenses, even for commercial use.
The new broadband service would use a tiered approach to accessing the frequencies, while also protecting existing users in the same band. This would require both access to FCC databases of existing users in a specific geographical area and the use of what the FCC is calling “sensing” technology in which wireless equipment would first listen on a specific frequency it intends to use before transmitting.
Currently, the frequencies involved range from 3550 to 3650 MHz, with expansion to include the next 50 megahertz, or up to 3700 MHz. The current occupants of these frequencies are primarily federal users, most of which use the frequencies for radar. There are also a few legacy satellite communications services occupying this region of spectrum.
The top tier is existing users of the band that are immune from interference. Tier two would consist of licensed wireless providers who must avoid interfering with existing users in the band, but who would be free from interference in lower tiers. Those licensed providers would gain their access through spectrum auctions. The third tier that the FCC will designate for the 3.5 GHz band consists of unlicensed users who are deploying the licensed radio equipment and who would be required to avoid interfering with other stations on higher tiers.
Unlike many spectrum assignment plans, the CBRS would not specify the type of use.
FCC Assigns Spectrum to Create Citizens Broadband Radio Service
Wireless providers could take advantage of the band for an expansion of LTE, for example, while broadband providers could use the band for fixed wireless. Some wireless Internet providers for rural areas are already in this band and the new FCC plans could allow more to enter it.
Initially there will be some geographical restrictions on use, especially near the coasts where there’s still some Navy radar using the frequencies. However, once the sensing technology is available, some of those restrictions, perhaps all of them, could be eliminated.
It’s worth noting that most Navy radar applications in this frequency range are sufficiently powerful that the biggest interference risk is to the CBRS equipment rather than the other way around. Those Navy radar applications have been known to fry seagulls instantly at distances of over a mile, and make objects containing water explode at shorter distances.
The FCC will vote on the CBRS on April 17, although it will take some time to put into effect. The cloud-based usage databases will take time to implement and the sensing technology will likely require some time to develop. This technology appears to be very similar to the CSMA technology developed by the University of Hawaii for its AlohaNet wireless network, which was the precursor of Ethernet.
Right now there seems to be general support for the whole idea of a new wireless broadband service, although the unstructured nature, the casual license requirements for portions of it and the fact that pretty much anyone can use it for pretty much anything is enough to give one pause.
This is especially the case given the connection being made at the FCC between the CBRS and the Citizens Band Radio Service, that favorite of long-haul truckers and others who frequently flout existing rules more than follow them. CB in the U.S. is known for its interference with global communications in its own 27 MHz band and in areas near it as users stray outside of the existing boundaries of the service.
Unless the FCC can find some way to rein in bad behavior, it would seem that an analogous broadband service might cause more trouble than it’s worth.
It means that the FCC will not only have to create some means of mandating sensing technology and usage databases, it will also have to find a way to prevent users from disabling it. Otherwise, the Citizens Broadband Radio Service could easily devolve into something as unregulated and abused as its Citizens Band precursor.