March - April 2003
Volume 2 - Issue 6
Volume 2 - Issue 6
In This Issue: |
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TechTime 
Wi-Fi, Hot Spots, 802.11, and YouIf you have not heard of Wi-Fi yet, you will soon. Wi-Fi is short for Wireless Fidelity, the popular name for 802.11 standard developed by the (IEEE) Institute of Electrical and Electronic Engineers. This is the same group that developed the 802.3 standard, which is commonly known as Ethernet. The most prevalent Wi-Fi standard is 802.11b, the standard for wireless LANs (local area networks) operating in the 2.4 GHz spectrum with a bandwidth of 11 Mbps (Megabits per Second). 802.11a is a different standard for wireless LANs operating in the 5 GHz frequency range with a maximum data rate of 54 Mbps. For additional information, refer to this side-by-side comparison of the two standards. Wi-Fi enables users to connect to the Internet without using wires. Wi-Fi networks are available on university campuses, in small offices, and in homes. In addition, "Hot Spots" are being installed in airports, bookstores, cafés, and hotels worldwide. Hot Spots are making it more convenient for people with laptop computers and PDAs (Personal Digital Assistant) to connect to the Internet. Wi-Fi enabled computers send and receive data anywhere within the range of a base station. In New England, many Borders Bookstores and Starbucks cafés are installing wireless base stations to become Hot Spots. Customers at selected McDonalds restaurants in New York who purchase an Extra Value Meal receive one hour of free high-speed wireless Internet access, or can purchase a single session of up to 60 minutes for $3.00. These companies hope that by giving people a place to search the Internet, check E-mail, or chat online, they'll stay longer and spend more money. On the University of Massachusetts Medical School Campus in Worcester (UMass Med), a wireless network has been available for years in the Lamar Soutter Library and is also available in the new Aaron Lazare Research Building. The installation of additional wireless access points is planned on the UMass Med campus over the next few months. Many hospitals are installing wireless networks to streamline the patron registration process and improve patient care. For example, in some hospitals, nurses can input patient data into the hospital's network, eliminating the need to take handwritten notes and input the data later. In addition, through the use of patient and medication barcodes, it is possible to verify prescription information at the patient's bedside -- reducing the chance of errors. The use of wireless networks can also provide bedside access to patient registration information, laboratory results, and radiology reports. Wireless networks are installed in homes to easily connect multiple laptops or PCs to the Internet and to each other. People enjoy the ability to access the Internet throughout their house and link multiple computers to each other without wiring their homes. What Makes Up a Wireless Network? The pieces that make up a wireless network are very similar to those required for a wired network. The Wi-Fi network consists of two basic components: Wi-Fi radios and access points. Wi-Fi devices "connect" to each other by transmitting and receiving signals on a specific frequency of the radio band. Wi-Fi radios are embedded or attached to desktop computers, laptops and mobile devices. The access points act as "base stations" -- they send and receive signals from the Wi-Fi radios to connect to the Internet, and if desired to each other. It is now common for laptop computers and mobile computing devices to come with a Wi-Fi radio as standard equipment. They are ready to operate without wires. For other laptops, a Wi-Fi radio embedded in a PC Card is inserted into the laptop's expansion slot. Many PDAs have a slot for a Compact Flash format Wi-Fi radio. In addition, small-format Wi-Fi radios for PDAs and mobile data devices are rapidly becoming available. Limitations As with any new technology, there are limitations. (Remember when cell phone coverage was limited to a few large cities?) For wireless networks, the three major limitations are Distance/Speed of Connection, Potential Interference, and Security.
A major limitation is the maximum distance transmitters can send and receive data. For the 802.11b standard, the coverage distance is up to 300 feet. Base stations are recommended every 200 feet is each direction. For the 802.11a standard, base stations are recommended every 50 feet. The connection to the Internet or LAN is slower the further away the Wi-Fi radio (laptop, PDA, etc.) is from the base station. Network interference is possible from any device that operates in the 2.4 GHz spectrum, such as cordless phones, microwave ovens, adjacent Hot Spots, and neighboring wireless LANs. "Interference between medical devices and wireless networks can be mitigated or eliminated," according to a White Paper (PDF) prepared by Cisco Systems, a provider of wired and wireless LANs. In addition, "wireless radios operate on a non-interference basis. This means that they may not cause harmful interference, but they must accept harmful interference, including interference that distrupts service." As a result, there is the potential that certain equipment may interfer with the network, but a lesser chance that the network will interfer with medical equipment. Wireless LANs (WLANs) are vulnerable to hacking since communication occurs "through-the-air" and the current standard for wireless networks, wired equivalent privacy (WEP), does not yet function properly. It is common for organizations to implement enhanced security software solutions that are available from a number of vendors to ensure privacy. These solutions utilize encryption, authentication, and data integrity to secure wireless communication. Encryption "scrambles" the transmitted data. Authentication is password control to enter the network. Data integrity ensures that system malfunctions or intruders have not altered information between the sender and the receiver. Many of the companies that sell wireless networks perform a site survey as part of the sales and installation process. This provides information on where to locate base stations for best performance and identifies potential interference issues. Requesting Your Input Is your organization using wireless technology, either within the library or the institution as a whole? If so, what are some of the benefits and what have been some of the challenges that had to be overcome? Contact me at penny.glassman@umassmed.edu to share your experience for a future issue of TechTime. Useful Links
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Penny Glassman, Technology Coordinator |
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