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March
2002 -
Volume 2, Issue 2
The
ABCs of Wireless Technology
What does
"wireless" mean?
"Wireless" means transmitting signals over invisible radio
waves instead of wires. Television remote controls were the first
wireless devices to become a part of everyday life. Now the cordless
keyboard and mouse, PDAs, and digital and cellular phones are widely
used.
How do wireless
networks work?
Wireless data is predominately transferred over two kinds of networks:
wide area networks (WANs) and local area networks (LANs). These
networks are similar to their wired counterparts-they just use radio
waves instead of copper or fiber.
WANs can cover
areas as large as several countries. Wireless LANs, already popular
in airports and hotels, are often used to replace or enhance wired
LANs. They can cover a range of 153 meters indoors and up to 305
meters outdoors. They may service a smaller area than their WAN
cousins, but LANs can transfer data much faster, at speeds up to
11Mbps. Wireless LANs are used primarily for data; they do not usually
support voice traffic.
What technologies
are involved?
First a word about how wireless technologies are referred to. You'll
read a lot about "generations" of wireless, which correspond
to the rate and quality of data and voice transmission. The first
generation was analog voice (the earliest cell phones).
The second generation is digital (such as more efficient cell phones
with voice and data at rates of 9.6Kbps to 14.4Kbps). Currently
carriers are working on what they call 2.5 generation, or 2.5G,
transmission rates, which will carry data up to 114Kbps. The future
is 3G, which will include multimedia and data transmission rates
of up to 2Mbps to 5Mbps, advanced roaming capabilities, as well
as the sought after (by some) "always-on" potential.
When it comes
to WANs, an alphabet soup of technologies is used to send data through
the air. One of the most used and talked about is wireless application
protocol (WAP). WAP-enabled devices offer a limited version of the
Web designed to work on the small black-and-white screens of phones
and PDAs.
Within the current
digital world of wireless, there are four primary technologies:
code-division multiple access (CDMA), global system for mobile communication
(GSM), integrated dispatch enhanced network (iDEN), which is used
by Nextel, and time division multiple access (TDMA).
Bluetooth, a
LAN technology, enables devices rather than a network to communicate.
With an operating range of only 10 meters feet, Bluetooth can be
used in a headset to wirelessly listen to audio on a computer and
send photographs from a digital camera to the computer.
What's the difference
between wireless and mobile?
A laptop is a mobile device. The Lotus Notes application on that
laptop is mobile because it resides on the laptop but needs to connect
through a wired modem connection before it can be used. A cell phone
is a wireless device. The Lotus Notes application on that cell phone
is wireless because it can receive data wirelessly-that is, without
being plugged into a wired connection.
What can
these technologies do for businesses?
Wireless applications include e-mail, paging, voice transmission
and Web access. Companies currently use wireless technologies to
connect laptops, mobile phones and PDAs to a wide variety of product
and customer information.
What are
the limitations?
First and foremost, you need to realize that wireless communications
will never be perfect. The experience will never mimic what you're
used to seeing on your PC.
When it comes
to WANs, bandwidth and spectrum are major limitations. The networks
are slow. When transmitting data, you're forced to send smaller
bits of data just so the information moves as quickly as possible.
The size of the device that's accessing the information is also
an issue.
Phones and PDAs have small screens-often only a couple of inches
in diameter-and it is not easy to see large documents on them. Think
of a contractor trying to read an architect's blueprints on a job
site.
When it comes
to voice transmission, you need to remember that wireless is a radio-based
technology, which calls for transmission towers and receivers that
are positioned to dodge interference.
Do I need
wireless?
Just because your company can go wireless doesn't mean it should-not
every company needs wireless.
Critical, time-sensitive
applications are the best candidates for WAN projects. If getting
information in real-time makes or breaks a sale, give your salespeople
access to that data. But remember that WANs are best suited for
accessing small pieces of information because of bandwidth constraints.
Wireless LANs
are often installed for convenience, such as when you don't want
to wire the building, or when your staff is dispersed throughout
the building. They are often used in hospitals, where doctors and
clinicians can check in while on rounds or on the floor. Wireless
LANs are faster and more reliable than WANs, and they can be similar
in price to wired LANs.
What's a good
strategy for getting a wireless project off the ground?
Start by figuring out what kind of information needs to be accessed,
by whom and from where.
Evaluate how
easily it will be to access the information that is going to be
sent out to wireless devices. Is the information coming from a variety
of sources? Is the information too large to be conveniently accessed
on a PDA or phone?
Start small,
with a pilot project. Not all projects will be scalable for a
larger rollout or more robust applications.
Keep realistic
expectations in mind. Ask the following questions:
· Coverage-how large an area am I asking my wireless to cover?
· Speed and bandwidth needed to run an application-will I
have enough?
· Device interface-does the application work well on a small
screen?
What are the
security risks associated with wireless technologies?
Most people with PDAs and phones don't use built-in security features,
such as password protection and locking keypads, and the data on
handheld devices is rarely encrypted. If a device is lost or stolen,
all the information on it can be accessed by someone else.
For WANs, there
is something called the WAP gap-the small window of time between
decrypting and encrypting information (usually performed by the
carrier, such as Sprint PCS) when there is vulnerability. However,
the chances of a breach are very low.
The most significant
risk is to LANs. The 802.11 family of specifications used for wireless
LANs relies on a protocol that has been broken. Without the proper
security measures in place, a wireless LAN can be accessed by anyone
with cheap equipment and hacking skills.
What about
using wireless technologies on a global level?
The idea of accessing wireless data services from anywhere around
the world on the same device is still a dream. Several U.S. wireless
carriers offer voice services on an international level, but they
do not offer data services.
However, global
enterprises could find faster wireless data services abroad. Services
in Europe and Japan are a few steps ahead of those offered in the
United States, which could make business applications more viable
for companies with foreign offices. Just don't expect them to work
seamlessly across national borders anytime soon.
What does
the future look like?
As in all industries, the economic downturn has changed the priorities
in the wireless world.
The industry
is now focusing on providing better, faster data and introducing
text services to consumers. Text messaging (known in Europe as short
messaging service-SMS), which includes e-mails, instant messaging
and paging services, already delivers alerts about things like flight
delays, sports scores and stock prices.
These services are expected to grow in popularity as the technologies
become more available. The most important characteristics of the
technologies and services that are leading the wireless world into
the future will be speed and constant connectivity.
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