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Wireless world awaits.

The 21st century may well be an end to the wired world. Already cellular telephones have gained international acceptance. Wireless computer networks have been introduced and developers are examining other uses for this connection technology.

Wireless is expected to become a factor in the further development of other computerized products such as electronic point of sale systems (EPOS) and automatic teller machines (ATMs).

If we were to examine the ceiling or the floor of a modern shopping centre or bank, we would see a maze of wires. Wiring is a fact of modern life. But that is about to change. Electronic cash registers and ATM machines will soon communicate without wires.

Wireless devices are flexible, for example, in the case of the EPOS, during peak periods, retailers could roll out additional systems to meet demand without needing to physically wire them into the store's computer system. In banking, wireless could introduce a new element in customer service; the portable ATM. In the future these machines may turn up at public events, as needed.

But, before wireless becomes a staple of electronics devices, some problems need to be resolved. Currently, radio broadcast technology has been used to connect computers in local area networks (LANs) in which workgroups of personal computers or workstations share information or peripheral devices.

One of the problems that is limiting wireless LANs is the need for appropriate radio frequencies. Each country has its own system of allocation.

Security is a Concern

There is also an unjustified concern about security. Actually, one of the major attractions of wireless computing is its security. Broadcast data, through encryption, can offer a level of security unmatched by a wired system. Wired signals (messages or data) travel around the wire itself. Because of this, it is relatively easy to pick up the signal by placing another wire near the one carrying the signal. Transmission across wires is usually digital and therefore very easy to decode.

One might argue that low power radio broadcast signals exist within a larger volume as opposed to the small cylinder surrounding a wire, and are therefore easier to access physically. And it could be said that typical radio modulation, such as AM or FM, is also relatively easy to decode. But what if the signal is modulated in such a way as to encrypt its content?

The approach used in computing to do this is known as 'spread-spectrum' and was designed initially for military purposes as a modulation technique to encrypt a signal with a spreading code so that a receiver could not decode the signal without knowing the spreading code. Two different techniques are used to encrypt the signal; one is known as frequency hopping and the other is direct sequence modulation.

Both spread the transmitted signal across a larger frequency band than necessary to transmit the signal. Frequency hopping moves the frequency of the narrow band signal around within a broad frequency bank in a pattern based on the spreading code. Direct sequence modulation transmits across the entire broad band, but at a higher signal rate. This is accomplished by multiplying the original narrow bank signal by a spreading code.


Reliability is an important issue. Today, the least reliable component of network is often its cabling. Data transmission reliability is linked to the reliability of the cabling itself. Then there is always the problem of accidentally cutting a cable. Most network failures are due to a problem in the cable component. Wireless eliminates this component.

Cabling is also subject to radio frequency interference, which is why most cable runs are limited to 150 feet. There is also the problem of locating a cable too close to incandescent ceiling lamps.

Spread-spectrum on the other hand is resistant to radio frequency interference. One of the original virtues of this technology was its immunity to radio by opposing military forces.

Although the spread-spectrum technology can work over considerable distances, its use may be limited by government regulation to very short distances. In the United States, for example, the Federal Communications Commission enforces a low power level requirement allowing a range of approximately 1,000 feet. This makes it suitable for most offices given that typical workgroups have diameters of some 200 to 300 feet. Connections beyond the workgroup, to other parts of the enterprise, will then have to be achieved through cable or other transmission systems.

Flexibility is Key

One of the greatest values inherent in a wireless approach to net working is flexibility. In today's wired environment, considerable effort is required to move computers or add additional systems. With a wireless system, computing resources can be placed wherever they are needed for however long they are needed.

The impact of wireless on computing is expected to be dramatic and industry analysts have declared that "copper is dead. Clearly fibre optics and radio technology will replace copper as a connection between computers".

While attention of late has focused on wireless local area networks, another technology has emerged as a prime candidate for wireless communication: the pen-based computer. Its use here may be revolutionary speculates Greg Blonder, director of the Materials and Technology Integration Research Laboratory, of AT&T's Bell Laboratories. "Quite frankly, the greatest use for the pen-based system may well be as a substitute for the telephone. If you can use it to maintain contact with other people and to exchange information, there may be less need for audio conversation on the telephone". He sees wireless communications as offering users the opportunity of being able to communicate with others without being actively involved in the communications process. "In other words we will be able to participate in other activities and still carry on communication."

Computer users, he said, will be able to walk about with their computers within a wireless area of their offices. When they are out of the office, they can use other means to re-enter their systems, such as cellular communications.

As this happens, the way we use computers will change, for one thing, they will no longer be stationary objects.
COPYRIGHT 1993 Canadian Institute of Management
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1993 Gale, Cengage Learning. All rights reserved.

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Title Annotation:wireless technology
Author:McGlynn, Joe
Publication:Canadian Manager
Date:Jun 22, 1993
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