Monday, April 04, 2005

You're Fibered!

What transmits data at gigabits per second from point to point using only a pencil-thin medium? Fiber optic cable, right? Yes, but a virtual fiber optic cable can work just as well and be a lot easier to install.

Virtual fiber? It's fiber optics sans fiber and sans optical frequencies. OK, it's radio waves. The millimeter wave bands of 70, 80, and 90 GHz were opened up for commercial use in 2003 by the FCC. Now GigaBeam has hooked up properties owned by none other than the legendary real estate developer Donald Trump with their product called WiFiber. Hey, there's an assignment for those "Apprentice" candidates. See who can beam together the most buildings in the Big Apple. The team with the most bandwidth wins, which is not a bad business metaphor anyway.

Millimeter waves are located in the EHF or Extremely High Frequency portion of the electromagnetic spectrum that extends from 30 GHz to 300 GHz. At those frequencies wavelengths are only a fraction of an inch. High gain antennas capable of forming tightly focused beams can be only a few feet in size.

That high gain is needed. At such short wavelengths, the signals tend to be absorbed by rain and even air. The 71 through 95 GHz frequencies are strategically located between two frequencies where oxygen more strongly attenuates radio waves, and below the submillimeter bands where water in the atmosphere makes it almost opaque. In the visible spectrum, fog is actually worse to penetrate than rain and can block Free Space Optical (FSO) beams that are also used as virtual fiber links.

You want a high gain antenna is to keep your radiated signal in as tight a beam as possible. The way antennas create gain is by focusing radio waves. A point source that radiates in all directions is called isotropic and has zero gain. But, take all the radio energy and send it out in a narrow beam and you've effectively boosted the signal in the beam direction just as if you had raised the transmitter power. Any spreading out of the signal to either side of the receiving antenna is essentially lost power.

Tight beams are also valuable for point to point communication because they don't generate interference to others and they are hard to intercept. Unless you are directly in the path of a millimeter wave signal you won't even know it is there. Millimeter wave transmissions can be focused into beams only 1 degree wide and 1 to 4 miles long. That works out well for secure links between buildings. Beyond the signal range, another system can be operating on the same channel without interference or detection. Off to either side, other millimeter wave beams on the same channel can serve other buildings in the same metro area. The radio signals can also be encrypted to further enhance security.

So what is Donald Trump doing with all that connectivity? It's to provide residents at Trump Place in New York City with high speed wired and wireless data service, VoIP, video on demand and high definition television. In this case, it's virtual fiber to the home.

For wired fiber optic and copper WANs, let our GigaPackets service find you the best prices available for your application.

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