Wednesday, August 17, 2011

On Super Wifi MANETs, Part 1




Today, I want to write on a subject that has been on the back of my mind for the last half-year.
Rewind back to 2007. That is when I first discover TEDtalks. And of the many riveting talks, one by Negroponte (then the head of MIT Media lab) leaves a particularly strong impression on me. It is on his "One Laptop per Child" project. With an ambitious goal of giving a $100 dollar laptop (specially designed for this purpose) to every child in the developing world. What impresses me at the time, is the fact that these laptops are able to form a "wireless mesh network" using their wifi antenna. That is the first time I hear of the term "mesh network". A quick research on the Internet tells me that "mesh networking is a type of ad-hoc network where each node must not only capture and disseminate its own data, but also serve as a relay for other nodes." The mesh networking capability of the OLPC laptops are also wireless (mobile ad-hoc networks, or MANET), but the essential idea is the same.

Fast-forward to September 2010. Many tech blogs and sites cover the imminent passing of the "super wifi law" by the FCC. In short, it is the decision by the Federal Communications Commission of the United States of America to free the white spaces (UHF TV band) for unlicensed data.




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A little history: the now-ubiquitous wifi technology was born out of a decision by the FCC back in 1985 to open several bands of wireless spectrum, allowing them to be used by anyone without the need for a government license. Recall that all wireless technologies were all born out of the War efforts during the Second World War, and as such were heavily regulated by the government. The bands that the FCC chose to release to the public was the 'garbage bands': 0.9GHz, 2.4GHz, and 5.8GHz, these were already allocated to industrial, scientific and medical equipments. Microwave ovens, for example, use 2.4GHz radio waves to heat up water molecules. As such, these bands seemed pretty much useless for communications purposes, and it's almost as if the UA government just opened them up and went "let's see what happens."


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So what does the FCC decision at the end of 2010 to release the 700MHz white space to the public mean? The most significant and obvious difference is the range. Whereas original wifi (and let's not forget Bluetooth) was good for about 50m, the new super wifi is good for 50 miles. It's an increase of more than three orders of magnitude.

Currently, smartphones access the Internet via two means. The First is via telecommunication network providers, using cellular frequencies. This includes GSM, CDMA, 3G, and 4G networks. The second is ones usually found in home networks and 'hotspots': that's right, the wifi.

But with the arrival of a long-range spectrum deregulation, the possibilities are seemingly endless. This is what I am hoping to write about in the next part.

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