Wireless Networks: New Meaning to Ubiquitous Computing. By: Drew Jr., Wilfred (Bill), Journal of Academic Librarianship, 00991333, Mar2003, Vol. 29, Issue 2

Section: MANAGING TECHNOLOGY

Imagine that you are a student walking from class. With a little time on your hands, you stop at the library to find some books and magazine articles for a paper you need to write. Going over to a study carrel, you pull out your IBM ThinkPad and log into the network. You go to the library home page and click on the online catalog. You do a search for some books on equine nutrition, e-mail the results to yourself for use in the bibliography, and head to the stacks to get the items on your topic currently available for loan. Laptop in hand, you walk over to the SF 285.5 section of the library and pull three books. In the stacks, you spy a student worker taking books off the shelf and running some sort of wand attached to a handheld computer over the inside of a book. He tells you he is doing inventory and shelf reading. On your way back to the carrel you stop and chat with some friends. They are working on a class project and have their laptops out looking for magazine articles in a library databases. One of your friends gets up and walks over to a printer across the lobby to get one of the articles. You see another student using a Palm PDA. She is getting assistance by “chatting” with the reference librarian. She then walks to the stacks to get a book suggested to her by the librarian, occasionally glancing down at her PDA to confirm the call number.

What is remarkable about this scenario? The students and the library worker are all using computing devices connected to the campus network and the Internet beyond. Yet there’s not a wire in sight, no power cord, no network cable. All the individuals are completely mobile, empowered to consult network-based resources anytime they want, and from any place, by a wireless network that “blankets” the entire library.

WHAT IS A WIRELESS NETWORK?

Here’s a little-known fact: The scenario above is possible, thanks in part, to one of the most beautiful Hollywood actresses of all time. In 1942, Hedy Lamarr and composer George Antheil patented the concept of spread spectrum.( n1) Many cellular phone systems use this technology to prevent interference from other radio signals. This technology is also key to modern wireless local area networks (WLANs).

A wireless network enables your device to stay connected to your wired network without a wire or network cable. WLANs use access points to receive and transmit radio signals to and from the user’s computer or other device. The user’s device has a special card that contains a small radio transmitter and receiver. The access point is hard-wired to the local area network (LAN) and via that to the Internet. WLANs allow users to roam (move from one point to another) without having to unplug a network cable from one jack and plug it into another. This is done by strategically locating access points to avoid breaks in coverage as the user moves around.

STANDARDS

Perhaps the most important event to happen in terms of wireless LANs was the creation of the IEEE 802.11 standard in 1997.( n2)

The Institute of Electrical and Electronics Engineers (IEEE) is a professional organization of engineers, scientists, and students. It develops standards for many things, including networking and computing. The 802.11 standard sets the protocols used between a wireless client (user’s device) and a base station (access point) or between two wireless clients.( n3) The earlier versions of IEEE-compliant networks performed in the 2 Mbps (megabits per second) range, but IEEE 802.11 has been revised and updated since 1997. The 802.1 lb, also called Wi-Fi (Wireless Fidelity), increases bandwidth to 11 Mbps. 802.11b is currently the most widely used standard and is in the 2.4 GHz frequency range, an unregulated frequency in which we are also beginning to see some cordless telephones.

There is also an 802.1 la version of the standard, which brings the potential bandwidth to 54 Mbps. 802.1 la operates at 5 GHz, a frequency used mostly by the military and not available in every country. According to Marshall Breeding( n4), 802.11a was supposed to be available mid-2002, yet as of this writing deployment of 802.11a networks has yet to be widespread. Since “a” and “b” networks operate at different frequencies, they are incompatible. To provide an 802.11a network would, therefore, require, at least for a time, maintainance of the 802.11b network as well. Also, as wireless network speeds increase, cell size, that is, the area covered by a given access point, shrinks, requiring more access points and/or a different arrangement of antennae. This means that 802.11a will require more access points to provide the same coverage as Wi-Fi, making it potentially more expensive than an 802.11b network. 802.11a is compatible with other international standards such as Hiperlan/1 and/2. This is a European standard set out by the European Telecommunications Standards Institute (ETSI). It sets the wireless LAN standards for most European countries.( n5)

Another wireless networking standard that has received a great deal of publicity is Bluetooth. Bluetooth, like 802.11b networks, operates at a frequency of 2.4 GHz.( n6) The problem with using Bluetooth is its limited physical range and bandwidth, about 30 feet with a bandwidth of 2 Mbps. (In contrast, 802.1lb has a range of 300 feet with a bandwidth of 11 Mbps.) Bluetooth has been designed primarily to connect various wireless devices together such as allowing your PDA to synchronize with your laptop or cell phone. Bluetooth is suitable for many applications but not for data networking purposes such as surfing the World Wide Web or accessing large files.
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