by September 3, 2009 0 comments



My two early experiences with Wi-Fi, were both to do with aviation, and both
in 2002-03.

In 2002, I got my first taste of public Wi-Fi at Singapore’s Changi airport,
which not only allowed free Wi-Fi access, but gave free PCMCIA cards if your
laptop didn’t have Wi-Fi (most did not). You had to deposit your passport to
borrow the card. So I spent hours shopping around Changi, with a baggage cart
propping up my laptop, all connected-stopping only once to recharge the battery.

In 2003, I had my first in-flight Wi-Fi experience. Lufthansa started testing
Wi-Fi on its flights from Frankfurt to JFK (New York), and it was free! So I had
a sleepless, all-connected nine-hour flight.

Today, several airlines provide Wi-Fi connectivity, and India’s carriers too
are contemplating it. But the world has moved ahead-to in-flight mobile
connectivity.

Mobiles are banned in flight, you say? Yes, but by whom?

Not by the FAA, the US aviation authority that is the benchmark for many
countries’ rules. But by the FCC, the US communications authority.

That’s because the ban is not due to aviation safety issues. It’s because the
mobile-phone system cannot handle in-flight use.

Our terrestrial mobile system works with cells, each a few miles across and
powered by a base station. The system expects you to be in one cell at one time.
When you move away, it switches you to the next cell. The frequency you’re using
is also re-used in other cells further away.

But when you’re high up in the air, you’re roughly the same distance from
dozens of cells, which confuses the system. It can’t even re-use your frequency.
And you’re moving at 800 km per hour, crossing a cell every 10 seconds! The
system would go crazy trying to keep up just with you. Now imagine ten others in
your plane making calls…

And mobile signals are weak up there. Your phone compensates, and begins to
transmit at maximum power, which isn’t good for your brain, aircraft avionics,
or your phone battery.

So our ‘terrestrial’ cellular phone system isn’t good enough to handle calls
from the air.

What’s the answer, then?
One is to use a different phone system. That was tried 20 years ago: phones
built into aircraft seats. At $10 a minute, few used them. Most airlines have
scrapped them now.

The better way is to let you use your mobile phone-through a picocell, a tiny
cellular base station installed in the aircraft. You connect to that picocell,
which in turn connects to a special ground station. The aircraft may also have
an EMI shield that stops your phone connecting to an outside network directly.
Airlines such as Emirates and Ryanair have already done this.

When you’re in air, seat-belt sign off, the crew switches on the picocell,
and you switch on your phone. You’ll see a new network, like ‘JetLite’, and
connect to it just as if you were roaming. You’ll pay the airline’s roaming
rates. Voice, data, SMS and all services will work (depending on what’s been
allowed).

That’s it, really. That’s how easily our planet’s last refuge from the
mobile-phone menace is about to be demolished.

The author is chief editor at CyberMedia, publisher of 15 specialty titles
including PCQuest. You can reach him at
pkr@cybermedia.co.in, twitter.com/prasanto.

No Comments so far

Jump into a conversation

No Comments Yet!

You can be the one to start a conversation.

<