EMERGING TECHNOLOGIES : Wireless Networks.

One of the most striking changes in the use of technology in the last year or so has been the explosive growth in the use of wireless networks for Internet and local network access. We will be looking in this column at the varieties of wireless connectivity now in use, including infrared, cellular, and Wi-Fi (802.11b), as well as those just now arriving on the scene, such as Bluetooth and 3G. The promise of ubiquitous wireless networks dramatically enhances the usefulness of small Internet-capable devices.

Infrared

Infrared (IR) ports have been standard on most laptops and PDA's ("personal digital assistants") for quite some time. Some printers and cell phones come equipped with infrared ports as well. The principal use has been to provide a communication channel between devices for synchronization, backup, or file transfer. The transfer rate is not as fast (4 Mbps or megabits per second) as wired connections (such as USB), although now some IR ports can transfer at a zippier 16 Mbps. IR ports are also used to transfer contact information or calendar entries between hand-held devices. This use is quite popular in Japan and Europe, particularly for exchanging business cards and downloading short messages. Utilities are available which allow for IR interoperability among Palms, WindowsCE/PocketPC devices, and even older Newton Messagepads (JetSend, Peacemaker, BackTalk). While IR is the granddaddy of wireless protocols, new applications continue to be developed for the its use, including InfoPort, a product for beaming large documents to Palm devices from kiosks or other public terminals (being used at the University of South Dakota for transferring documents to students), and Infrared Financial Messaging (IrFM), a new "point and pay" wireless payment standard. Financial transactions, in fact, are seen as a major future use of IR, as it is a more secure means of communication than other wireless protocols, since devices have to be lined up in close proximity to one another.

What allows communication among digital devices through infrared is a common set of specifications developed by the Infrared Data Association (IrDA) and first published in 1994, the most significant of which is the Object Exchange protocol or OBEX. A project is underway at the University of Tromso (Norway) to develop an open source implementation of OBEX which promises to make available OBEX functionality without license fees (to Extended Systems). In a rare example of not re-inventing the wheel with each new technological advance, OBEX has been selected as the standard for file exchange on the new Bluetooth wireless protocol. IrDA capability is built into mainstream operating systems including MS Windows, Linux, and MacOS. But IrDA compatible ports are also being added to devices such as cameras (the Casio WQV3 cameras) and scanners (Hewlett-Packard CapShare and the QuickLink Pen from WizCom). Scanning text or images into a hand-held scanner, which can then be beamed and stored on a hand-held computer offers interesting possibilities for collecting such materials as newspaper clippings or realia for language learning purposes.

Bluetooth

A wireless protocol which has been highly touted in the last several years is Bluetooth, developed originally by Ericsson in Sweden in 1994 and named for Harald Bluetooth, the Viking king who united Denmark and Norway in the 10th century. Bluetooth uses a short-wave, always-on radio signal that lets devices of all kinds communicate with one another, including cell phones, printers, laptops, and hand-held computers. Since it uses RF (radio frequency) waves, communication does not require a line-of-sight connection between devices, as does IR. Like IR, Bluetooth is short range (the normal limit is 10 meters) but is also omnidirectional and can travel through non-metal obstructions (clothes, furniture, walls). Longer range transmitters, capable of sending signals up to 100 meters, are also being developed. Bluetooth transmits at a maximum rate of 1 Mbps.

There has been quite a buzz about Bluetooth and the era of "personal area networks" (also being called "piconets") or "information clouds" this wireless technology promises to create. The idea is that once Bluetooth components become inexpensive enough (from the current US $20 to US $5), they will become embedded in all kinds of machines, including VCRs, washer-dryers, stoves, microwaves, and CD-players, all of which could be monitored and controlled by Bluetooth. Ericsson envisions a scenario in which mall shoppers would access sales information on their PDAs as they stroll, or cameras might send instantly pictures to relatives as they are taken. For some, this kind of all-encompassing network is more threatening than enticing. Of interest to language teachers is the fact that Bluetooth supports voice as well as data.

Others see a more modest role for Bluetooth principally as a cable replacement technology, taking over the role of wired serial or USB connections. In contrast to IR, Bluetooth allows point-to-multi-point connections, thus creating an ad-hoc wireless connection of "master" and (up to seven) "slaves." Also, as opposed to IR, Bluetooth communication can be initiated by the devices themselves, allowing for self-monitoring and automated interactions. Given the proliferation of cell phones in Europe, Bluetooth is expected to gain a foothold there first. It is already incorporated into a variety of phones available in Europe.

Wi-Fi

If Bluetooth is being promoted as a cable replacement technology, Wi-Fi is seen widely as a replacement of wired Ethernet. Actually wireless LAN (local area network) technology has been around since the late 1980's. However, different proprietary approaches were used, and the networks operated at low-speed (1-2 Mbps). In 1997, the standards setting body, IEEE, released the 802.(11) standard for wireless local area networking using the unlicensed 2.4 GHz frequency band (as opposed to the 900 MHz band used previously). This standard was later updated to 802.11b, which raised the transmission speed from 2 to 11 Mbps, or approximately the same transmission speed as traditional wired Ethernet connections. This is the standard generally referred to today as Wi-Fi ("wireless fidelity") or wireless LAN. As opposed to Bluetooth, Wi-Fi requires use of a "base station" or "access point" for transmitting signals to clients, which generally use Wi-Fi PC cards or desktop adapters to connect to the base station. Like Bluetooth (which also transmits at 2.4 GHz), Wi-Fi signals can travel through solid objects, although they traverse better through wood or drywall than through stone and brick. Transmission distances vary from 50 to 300 feet, depending on equipment and configuration, and can be extended up to 20 miles through the use of high gain antennas.

Wi-Fi began to be widely used when in 1999 Apple introduced its "Airport" wireless networking technology which uses the 802.11b standard. Apple integrated antennas for Wi-Fi into all of its laptops and offered an attractively priced base station capable of communicating with up to 10 clients (the latest version serves 50 clients). Today many Wi-Fi base stations and adapters are available from a variety of vendors. As prices have dropped and vendors multiplied in the past year, wireless networks have sprouted throughout the US in homes, schools, and offices. The home growth in the US has been driven in part by the increasing popularity of higher-speed Internet access through cable and DSL ("digital subscriber line") modems. Base stations such as Apple's Airport allow sharing of an Internet line by multiple users. Since DHCP ("dynamic host configuration protocol") is built into the Airport hub, all devices can share just one IP number. The base station can be connected to a dial-up or Ethernet Internet connection. Some base stations (such as those from D-Link, Linksys or Nokia) incorporate firewall support.

Mixed networks of Windows, Mac and/or Linux computers can co-exist quite comfortably and easily on the same Wi-Fi network, along with network-capable printers and mobile devices equipped with Wi-Fi cards. Individual configuration of Wi-Fi connections is not difficult; MacOS and WindowsXP automatically detect the presence of Wi-Fi signals (assuming a Wi-Fi client card is installed) and walk the user through set-up of the network for Internet access. Some Wi-Fi enthusiasts have taken to trolling urban areas for available Wi-Fi networks (comprehensive world-wide guides are also available). In fact, the ease and power of Wi-Fi networks has led to the establishment of wireless freenets in several urban areas in North American and elsewhere. With a series of base stations and antennae, it is not difficult to set up such a network, which some dub "parasitic grids." In the aftermath of the September 11 tragedy several such networks were quickly established in Manhattan (such as NYCWireless). Others see such "renegade wlans" as a way to bridge the "digital divide", bringing Internet access to the inner city. Commercial Internet providers are also now beginning to offer Internet access (for a fee) through Wi-Fi, especially in smaller communities. Wi-Fi connections are also showing up in public and commercial spaces such as airports or coffee shops, where connections are available for a fee.

Despite Wi-Fi's popularity there are several concerns in its use voiced by users and system administrators, namely limited bandwidth, radio interference from other devices, and security. A revision of the specification called 802.11a addresses these issues, at least in part. Although Wi-Fi runs at about the same speed as 10 Mbps wired Ethernet, configuration and security concerns usually reduce throughput to something more like 5-7 Mbps. 802.11a runs at the higher speed of 54 Mbps, although real-world use will be lower. This is still a significant increase for applications needing higher bandwidth such as streaming media. Wi-Fi runs on a radio frequency (2.4 GHz) shared by microwave ovens, most cordless phones, and Bluetooth devices, creating the potential for serious interference problems. 802.11a runs at 5.4 GHz, thus avoiding that conflict. Both wireless standards have a built-in security protocol called WEP ("Wireless Encryption Protocol") which allows for encrypted transmissions. Often, however, WEP has not been used on Wi-Fi networks out of concern that throughput will be negatively effected. The higher bandwidth of 802.11a may encourage greater use of WEP. Security experts, however, point out that WEP is not impenetrable and recommend use of VPN ("Virtual Private Network") software for secure network access with wireless clients. A new security protocol, 802.1x, is just being added to Wi-Fi setups (and is supported in WindowsXP).

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