How Hawaii Began to Turn the World Wireless

It is easy to grasp the importance of Wi-Fi today, even though pretty much of it is taken for granted. Setting up a home network, checking e-mails in a coffee shop or making up for tardy 3G coverage on a smartphone is now pretty seamless and straightforward. It was not always so.

Since its beginnings in the 1970s at the University of Hawaii engineers have overcome almost insuperable technical hurdles. At the same time competing companies have created standards using spectrum reserved for microwave ovens and the like. It is a story that deserves to be told, but it is easy to see why writers would shy away.

This is a subject where complexity and acronyms are impossible to avoid entirely. But Ars Technica has managed to make the tale of the development of Wi-Fi surprisingly compelling and there is useful practical information as well.

One of the key challenges, for instance, is ensuring overlapping networks can co-exist.

“It’s not uncommon to see a dozen or more Wi-Fi networks in a residential neighborhood. Fortunately, just because they’re there doesn’t mean that all of these networks are going to interfere much. Most networks are idle most of the time—statistical multiplexing for the win. However, if you find yourself stuck between active Wi-Fi networks, it can pay to experiment a bit.

“In some cases, the best choice is to select the same channel your neighbors are using. That way, your network and theirs will politely take turns transmitting. Waiting for your neighbor’s transmissions will reduce your maximum throughput, but they also wait for you, so you get to transmit at maximum speed when it’s your turn. Alternatively, if you choose a channel that heavily overlaps with a neighbor’s network that is both strong and active, the two networks won’t “see” each other and rather than take turns, generate interference when they both transmit at the same time, reducing the usable transmission rates.

Suggesting that you should try using the same Wi-Fi channel as a neighbor does sound counter-intuitive, but the explanation’s not too hard to follow. Much the same can be said of the whole article.

Ars Technica : Cutting the Cord: How the World’s Engineers Built Wi-Fi

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