Yakety Yak, Yakety Yak

Thu, 03/31/2005 - 7:00pm
Jeffrey Krauss, President of Telecommunications and Technology Policy

The FCC has three proceedings underway that will let airline passengers gab on their phones throughout the flight, not just before the plane takes off and after it lands. Just yesterday I was on a flight and the lady behind me was shouting into her cellphone, until they closed the doors and she finally had to turn it off. Sigh. One of the major players that pushed the FCC in this direction was the Federal Air Marshal Service, which needs air-to-ground communications for its marshals.

Anyway, the FCC is looking at minimizing barriers for the use of three different frequency ranges for airline passenger communications. The first is the 849 MHz to 851 MHz and 894 MHz to 896 MHz range, now used exclusively by Verizon Airfone. The second is the cellphone frequencies at 850 MHz and 1800 MHz. The third is Ku-band satellite technology.

The existing Airfone license was granted in 1990, and then Airfone was acquired by GTE, which was then acquired by Verizon. The FCC Rules provide for six licenses, and for awhile there was a second air-to-ground operator in this band, ClairCom, but that service was shut down in 2002. The FCC Rules divide up this small amount of spectrum into narrowband channels, 6 KHz wide. That is barely adequate for voice, and useless for data. According to the FCC, Airfone usage has declined sharply in recent years.

As a result, the FCC has decided that it will not renew the Airfone license. It will instead adopt a new channel plan that supports two licensees, and auction the spectrum to new entrants. Instead of narrowband channels, there are alternative channel block plans, consisting of pairs of either non-overlapping 500 KHz and 1500 KHz blocks, or two 1500 KHz blocks that partially overlap. These would be suitable for technology similar to the latest cellphone designs such as CDMA2000 1×EV-DO and GSM EDGE, which can support data rates up to 2.45 Mbps and 384 kbps, respectively. A pair of 1.5 MHz blocks can support numerous voice calls, and even a pair of 500 KHz blocks can support e-mail and messaging. Rather than picking one channel plan now, the FCC will allow bidders to specify which plan they are bidding on, and will adopt the channel plan that brings in the highest total aggregate bid for the two licenses. To promote competition, the FCC will not allow one entity to hold both licenses.

Those 800 MHz blocks today are used for the link between the aircraft and the ground stations, with wires connecting the phones in the passenger seatback to the 800 MHz terminal. But the passenger phones don't have to be hard-wired. In a separate proceeding, the FCC is looking at allowing passengers to use their own cellphones for that link. Your cellphone could communicate with a "pico cell" onboard the plane. The pico cell would direct your cellphone to operate at the lowest possible power setting. In this scenario, the cellphone would not communicate directly with ground-based cell sites; other frequencies, either at 800 MHz or perhaps 700 MHz TV frequencies or frequencies around 2 GHz, would be used for that link.

In any case, the FCC is thinking about eliminating its rule that prohibits airborne use of cellphones. The FCC rule exists to protect against a cellphone interfering with cellular networks on the ground. Interference is possible because, unlike cellphones used on the ground, there is no shielding afforded by buildings and by the curvature of the earth when the transmitter is six miles up. But cellphone network design has changed since that prohibition was adopted in 1991, so the FCC thinks that maybe direct communications from airborne cellphones to cell sites on the ground will work without causing interference. And, oh yes, even if the FCC removes its interference protection rule, there is still the issue of interference from cellphones to the onboard air navigation systems, and that's the FAA's jurisdiction. (But see "Investigation of spurious emissions from cellular phones and the possible effect on aircraft navigation equipment," IEEE Transactions on Electromagnetic Compatibility, Volume 45, May 2003, which seems to show there is no problem.)

Finally, the FCC is developing rules for additional Aeronautical Mobile Satellite communications services. Some aeronautical satellite service is already provided by Iridium, Globalstar and Inmarsat, but these are not passenger services. Last year, Connexion by Boeing launched a passenger service that uses WiFi or Ethernet within the aircraft, and a Ku-band satellite link from the aircraft to the satellite to the ground. This service has a 5 Mbps forward link and a reverse link of 512 kbps. It operates under a special authorization, and the FCC is now beginning to adopt general rules. Boeing projects that by 2010, about one-third of all commercial aircraft will have Connexion by Boeing service.

And the rest of the world's commercial aircraft? They'll be signed up by ARINC's SKYlink service, by the SITA/Airbus/Tenzing OnAir service, or by the Hughes/Row 44 service, all of which are satellite-based services in the planning stage.

Eventually, you won't be able to escape the chatter. It's bad enough to have to listen to the lady behind me while the plane is on the ground. With Connexion by Boeing and a VoIP phone, you can talk non-stop from Frankfurt to San Francisco.

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