WNA

Qualcomm and other companies are urging the FCC to open the 10.5 GHz band for wireless communications. Using Authorized Shared Access technology would allow the spectrum to be shared with licensed mobile operations when and where incumbents are not operating, says Qualcomm.

The FCC has invited public comment on the Petition for Rule Making (RM-11715) that would make a significant portion of the 10.0 to 10.5 GHz band available for wireless broadband services.

Authorized Shared Access technology has already been slated for the 3.5 GHz band, and Qualcomm said it “can similarly allow the 10.0 to 10.5 GHz band to be integrated into mobile networks and provide a predictable quality of service when and where incumbent users are not operating.

Qualcomm’s filing with the FCC builds on a petition for rulemaking filed by Mimosa Network pointing out that the 10 GHz – 10.5 GHz band, which is currently allocated for radio location and amateur radio use, could be used for mobile broadband applications.

“Opening access to the 10 GHz band using ASA and small cells should be given serious consideration because it can enhance and expand mobile broadband network capacity,” Qualcomm noted.

In the 70s, Xerox once wanted to become a player in telecom and got the FCC to allocate 10 GHz band for a PtMP wireless service it called X-Ten (Xerox Telecommunications Network). The plan was to bypass local telephone company wires and offer document interchange service to businesses. This was before email, and the documents would be scanned in as faxes for transmission. It later abandoned the whole thing.

CED columnist Jeffrey Krauss reviews the early history of “Digital Electronic Message Service” (DEMS), above 10 GHz. The FCC allocated more spectrum for DEMS at 18 and 24 GHz for wireless backhaul.

• Teligent acquired licenses for DEMS spectrum at 24 GHz and built out local networks in about 25 markets. But Teligent was never able to compete with telephone company services and filed for bankruptcy in 2001.
  
• Winstar, which planned to deploy local networks based on microwave licenses at 39 GHz, also filed for bankruptcy.
  
• First Avenue Networks later substantially bought all of the assets and fixed broadband wireless operations of Teligent and merged with First Avenue.
  
• First Avenue Networks merged with FiberTower in August, 2006, resulting in an installed base in 12 markets with more than 1000 sites.
  
• FiberTower also bought the spectrum assets of bankrupt of ART (at 39GHz) and combined them with Teligent (at 24 GHz), for licenses in the top 77 metropolitan areas. Their 24 GHz spectrum portfolio included, on average, over 230 MHz.
  
• Competitor XO Communications currently has licenses in the 28 GHz to 31 GHz frequency bands covering 73 major U.S. metropolitan cities.
  
• FiberTower went backrupt in 2013.
  
• Northpoint Communications convinced the FCC to create the Multichannel Video Distribution and Data Service (MVDDS) in the 12.2-12.7 GHz band, the same band used by DirecTV and Dish Network. Northpoint argued that since home satellite dishes all point to the south, that same spectrum could be reused by roof-mounted dishes that point to the north. Some companies bid and won the auctions for MVDDS licenses, but none of them built successful networks.
  

Mimosa’s proposed power limit of 55 dBW EIRP is very high, particularly for point-to-multipoint operations.

The Equivalent isotropically radiated power (EIRP) = Tx Output Power (dBW/dBm) + Antenna Gain (dBi) – Line Loss. So (30 dBm or 1 W of power) + 23 dBi of antenna gain = 53 dB (200 Watts). Give or take. Fixed point-to-point U-NII devices operating in the 5.725 to 5.825 GHz band may employ directional antennas with a gain up to 23 dBi, without any corresponding reduction in the transmitter peak output power.

Point to Multipoint antennas in the 5.8 GHz band are far more restricted in power. There is a 4-watt (36dbm) upper EIRP limit for a PtMP link. That’s equivalent to a 1-watt radio and a 6-dBi gain antenna.

Currently, Ubiquiti’s AirFiber has set the standard in 24 GHz at $3K for 700 Mbps while SAF, Trango, and others have announced similar products at $5000 or less.

Ubiquiti offers airMAX systems for the 900MHz, 2.4GHz, 3GHz, 5GHz, 6GHz and 10GHz bands, but their 10 GHz gear is not available (or legal) in the United States. If the 10.0-10.5 GHz band is allowed higher power, under the UNI-II upper rules, possibly with contention, then WISPS will have a new competitive tool, says Rory Conaway at MuniWireless.