past 10 years, cellular telephones (wireless devices that can access networks
and inter\intra nets) have evolved from a rarity
to an everyday accessory These
and other wireless devices prompted the International Telecommunications Union,
the Institute of Electrical and Electronics Engineers, and the European
Telecommunications Standards Institutes to develop standards for wireless
Users of such
devices have the flexibility,
convenience, and canaccess information from any location.
Other wireless technologies include the microwave, satellite, radio
frequency transmission, and various cellular services.
. Examples of approaches to wireless activities include
Wireless Local Area Networks (LANs), Infrared and Spread Spectrum Technologies,
Wider Area Wireless Networking, Specialized Mobile Radio, Cellular Digital
Packet Data, Microwave Technology, Satellite Technology, and Personal
Communications Services (Littman, 1998).
products are deployed in schools K Ė12, colleges, and universities where there
use is providing campus-wide
connectivity for students, teachers, and administrators.
Wireless LANs offer a
lowcost solution to high speed Internet access with the flexibility to meet the
needs of an everchanging educational landscape (www.aironet.com).
The integration of technology with education is rapidly changing
teaching/learning paradigms and environments.
technology, provides its users with access to information without looking for a
place to plug in, and network managers with
the capability to set up or augment
networks without installing or moving wires.
The advantages of being wireless include
mobility, installation speed and simplicity, installation flexibility, reduced
cost of ownership, and scalability. Consequently,
wireless communications are connecting more people and information, faster, and
more cost effectively than ever before.
All wireless communication, whether analog, voice, or digital data consists of
electromagnetic waves traveling through the air.
These waves determine the frequency
(number) of crests that move past a point in one second.
The shortest waves have the highest frequency (number of cycles per
second); the longest have the lowest frequency.
One cycle per second is called a hertz (Hz).
One kilohertz (kHz) is 1,000 cycles per second; one megahertz (MHz is a
million cycles per second; and one gigahertz (GHz) is a billion cycles per
second. Wavelengths range from a
high of100,000 meters (270,000 feet) to a low of 1 mm (.004 inch) and
frequencies range from 3 kHz to 300 GHz. The
full range of wavelengths and frequencies is
called the spectrum. The
frequency and wavelength of different parts of the spectrum determine how it is used.
Generally, the shorter the wave and the higher the frequency, the more
limited the range (Stalling, 1998). In
the U.S., the Federal Communications Commission (FCC) regulates the spectrum;
assigns frequencies and operating power and
both inspects and regulates
the use of transmitting equipment (www.fcc.gov).
Wireless telecommunications networks have been deployed in growing
numbers throughout North America and elsewhere in the world.
These wireless networks evolved from early microwave and satellite forms
to cellular, personal communications systems (PCS) and enhanced specialized
mobile radio systems (SMR).
Microwaves are very short waves in the upper range of the radio spectrum
used mostly for point-to-point communications systems.
Microwave transmission can handle all types of information, such as
voice, data, facsimiles, and video, in either an analog or digital format.
As the nation's cellular and personal communications systems grow,
point-to-point microwave facilities enable these wireless systems to serve the
country less populated areas on an economical basis (Gold, 2000). Early technology limited the operations of these systems to
radio spectrum in the 1 GHz range; but due to improvements in solid state
technology, commercial systems are transmitting in the 40 GHz region. This
spectrum offers a variety of possibilities, such as use in, short-range, high
capacity wireless systems that support educational and medical applications, and
wireless access to libraries or other information databases (www.fcc.gov).
Satellite technology is another form of wireless technology, which uses
microwave technology at high frequencies and is for wide area communications.
Its major advantage is that it can deliver services to remote locations
which cannot be easily accessed through traditional communication methods (Littman,
As defined by Littman (1998), ďa wireless LAN (WLAN), is a
communications network capable of supporting wire-free interconnectivity for
mobile users within an office, a building, or a group of buildings in a confined
geographical location such as on a university campusĒ.
A typical WLAN configuration is a backbone wired LAN that supports
servers, workstations, and one or more bridges or routers to link with other
networks. A control module acts as
an interface to a wireless LAN. The
control module includes either a bridge or router which then link the WLAN to
Another use of WLAN technology is to connect LANs in nearby buildings. A wireless link can be point to point between two
buildings using bridges or routers.
A wireless link can also be between a LAN hub and a mobile data terminal
such as a laptop computer. Anyone
with a wireless laptop can communicate with students and colleagues and transfer
data from the laptop to a desktop computer on campus
A WLAN must meet the same requirement of any typical LAN which include
high capacity, ability to cover short distances, full connectivity among
attached stations, and broadcast capability (Stalling, 1998).
Wireless Implementation Standards
network protocols and interfaces to support ubiquitous information access for
mobile and wireless hosts so that computing sessions initiated in one location
can continue without disruption when the user moves to a different location are
under investigation (Littman, 1998). The
Wireless Application Protocol (WAP) is an emerging standard for the presentation
and delivery of wireless information and telephony services on mobile phones and
other wireless terminals. WAP uses
existing industry standards as the basis for its own architecture and design.
For example, a WAP gateway is required to communicate with other Internet
nodes using the standard HTTP protocol. Furthermore,
the specification calls for wireless handsets to use the standard URL addressing
scheme to request services. The WAP
specification is an open standard that enables public content, corporate
Intranet and operator specific solutions to reach wireless subscribers.
It extends existing Internet standards, enabling application developers
to tailor their content to the special needs of wireless users (www.wapforum.org).
generation (3G) mobile devices and services are transforming wireless
communications into on-line, real-time connectivity.
It will allow users to have immediate access to location specific
services that offer information on demand.
The rapid and efficient deployment of new wireless data and Internet
services has emerged as a critical priority for communications equipment
manufacturers. Network components
that enable wireless data services are fundamental to the next generation
network infrastructure. The
recently adopted global 3G wireless standard will address emerging user demands
and provide new services. The
concept of 3G wireless technology represents a shift from voice-centric services
to multimedia oriented services. In
addition, heavy demand for remote access to personalized data is fueling the
development of applications such as SAP and multimedia management to complement
the 3G protocols. Complementary
standards, such as Bluetooth, will enable interoperability between a mobile
terminal and other electronic devices such as a laptop, desktop, and
peripherals, providing added convenience to the consumer and allowing for the
synchronization and uploading of information at all times (www.trillium.com).
wireless technology is a standard, as well as a specification for short-range
radio links between mobile computers, mobile phones, and other portable devices.
The Bluetooth Special Interest Group is an industry group consisting of
leaders in the telecommunications, computing, and network industries that are
driving development of the technology and bringing it to the public.
These companies consist of Intel, 3COM, Ericsson, IBM, Motorola, Nokia,
and Toshiba (www.bluetooth.com). Bluetooth
technology was developed to provide a wireless connection between small mobile
devices and their peripherals. The
targets were mobile computers, the mobile phones, small personal digital
assistants, and peripherals. It
allows for the replacement of cables that connect one device to another with one
universal radio link. It also
provides a universal bridge to existing networks, a peripheral interface, and a
mechanism to form small private groupings called piconets of connected devices
away from a fixed network infrastructure.
Broadband access technology has the capabilities to deliver service to the
markets not served by other technologies and compete on reliability and price.
Broadband digital wireless systems operate in the microwave regions above
1 GHz. They can be delivered through multi channel multipoint
distributions system (MMDS), and local multipoint distribution services (LMDS).
The LMDS are the newest type of broadband wireless network, and is set up
on the hub and spoke model with a base station antenna transmitting and
receiving to and from individual subscribers.
Most LMDS systems use the asynchronous transfer mode (ATM) protocol at
the core of the network. This
allows services to be provided on a bandwidth on demand basis, which
accommodates the need for multimedia applications and differences in user
traffic patterns. MMDS has been
historically used to deliver one-way TV cable broadcasts to homes.
It can now provide two-way digital broadband access after the FCC revised
its one-way restriction on the frequency band in 1998.
MMDS is delivered via a rooftop antenna to a box in the userís
location. Its signal can travel up
to 30 miles, and can be deployed in metro areas with only a few base stations.
Fading and line-of-sight concerns remain a consideration with the
implementation of this technology (Smith, 2000).
satellite data service has the speed or return path capabilities to compete with
cable, DSL, or LMDS in the larger broadband marketplace.
Satellite systems are costly to launch, but
Satellite do offer high bandwidth, a high degree of frequency reuse, and
unrivaled geographical coverage. Although
expensive, the amount of infrastructure required to provide a satellite service
is much less than in terrestrial networks.
As the market moves more and more toward global services, satellite
technologies will likely become a much bigger contender for a share of the
wireless technology marketplace (Fowler, 1998).
Wireless Applications and Providers
Infrared electromagnetic waves have frequencies higher than microwaves but lower
than the visible spectrum. Infrared
transmission is used for wireless LANs, as well as for point-to-point
communications with portable devices. Infrared
limitations include signal fading and line-of-sight requirements.
Spread spectrum is a wireless communication in which the frequency of the
transmitted signal is deliberately varied according to a specific mathematical
function. The signal is spread over
a large segment of the electromagnetic radiation spectrum to prevent it from
being intercepted. Although it uses
much more bandwidth than a constant signal a major advantage is that the signals
produced can penetrate walls and other obstructions (Littman, 1998).
Specialized Mobile Radios (SMRs) are primarily used for voice
communications, but systems are also being developed for data and facsimile
services. Additionally, the
development of a digital, rather than analog, SMR marketplace is allowing new
features and services, such as two-way acknowledgment paging and inventory
tracking, credit card authorization, automatic vehicle location, fleet
management, inventory tracking, remote database access, and voicemail.
Wireless communication companies have multiplied quickly. There are more than 50 million wireless telephone users in the US. Satellite systems, such as Iridium and Teledesic are developing worldwide data and communications services. As the technology is more reasonably priced, wireless could replace wired telephones as the medium of choice in America. Wireless technology uses in education can now offer low-cost solutions to high-speed information access with the flexibility to meet the needs of the ever-changing educational landscape. A growing number of applications required by businesses and educational institutions require mobility and simultaneous access to a network. Until recently, if an application required information from a central database, it had to be connected to a wired network. Wireless LAN enables mobile computers to be in constant contact with servers and each other. This section describes some wireless applications in current use in the corporate as well as the education arenas.
The mobility of wirelessness is needed and could be
used in health care facilities, warehouses, restaurants, and in real
estate and sales. Having the
flexibility and freedom to move laptop computers anywhere in any
environment, enhances productivity.
The transportation industry requires mobility and real time connectivity
over large areas. Retail businesses require flexible networking, fast
reconfiguration and redeployment of resources.
Health care providers need to have easy
access to many types of medical records and to specialists
for assistance as well as to computer-controlled medical equipment, from the
point of care. Wireless access can
also be effective in manufacturing facilities where robots and other mobile
automated equipment are already used.
In January 2000, IBM and Motorola announced a partnership under which the
two companies will develop wireless
Internet technology for cars. Users
will be able to send email, check on stocks, or engage in impulse buying while
they drive. The first
of these devices could
appear in cars as early as 2002 (www.wirelesstcp.net).
Personal Digital Assistant (PDA) development is advancing rapidly because
of advances in wireless technology. Using
a PDA with a wireless Internet connection, one can check e-mail, access web
channels, browse web sites, or synchronize the PDA with a host computer or
server. The range of PDA task
capabilities is increasing quickly as software innovations for such assistants
blossoms with access and use. Bluetooth
technology, for example, enables
PDAs to exchange information, connect to the Internet or LANs, or conduct
e-commerce. Cellular Digital Packet Data (CDPD) is a packet data protocol
designed to work over the original cellular network or as a protocol for a
digital air interface technology used in cellular and personal communications
services. The wireless mobile technology with the fastest data rate used in the
United States at this time is the Cellular Digital Packet Data (CDPD), which has
a top rate of 19,200 bps. At this
time, CDPD coverage is limited to major cities.
wireless computer devices have been developed and tested at Carnegie Mellon
University. The military, business,
and industry have used these 2-pound devices for a variety of purposes.
To accommodate workers, who need their hands free Carnegie Mellon designed
wearable computer devices that operate by voice or handwriting recognition.
monitors work like a miniature dashboard, allowing users to obtain information
without blocking their vision. Current
users of wearable devices include the National Science Foundation, the Defense
Advanced Research Project Agency, Intel, AT&T and IBM.
One disadvantage to the use
of wearable computers is the
current lack of access to high-speed wireless bandwidth (www.wirelesstcp.net).
many more uses of wireless technology in academe than can be described here. A
few examples will be provided. The
Florida State University College of Law in Tallahassee has installed a wireless
LAN to give its students wireless computer connectivity on its campus.
Professors can download casework directly to students through the
college's Intranet. In the
classroom, professors can send real time handouts directly to student laptops.
The wireless connection offers total
freedom and access to the network from
anywhere on campus, from classroom to courtyard to law library. The school is also doing a pilot
distance learning experiment. Students
are connected via wireless devices
to an ISDN line and are taught remotely by a Chicago Kent College Law professor.
With the wireless infrastructure, the curriculum and support material can
be delivered real-time via the Internet. Aironet
and the Florida State College of Law are also developing a joint pilot project
to test the efficacy of wireless LAN devices in the Tallahassee municipal court system.
When students at Greenville College in Greenville, Illinois need to access the
Internet, they simply turn on their computers-anytime, anywhere on campus. The wireless network technology allows students, teachers and
college administrators to roam freely around campus using their laptop computers
in any classroom, campus dorm room, or sitting on a park benche in the middle of
a campus lawn. Students
have instant access to information, and
take tests and quizzes on line, attend classes outdoors, or in
venues other than the traditional classroom setting. Princeton's Computer
Science Department decided to test the efficacy of wireless connections to the
Local Area Network (LAN) linking departmental offices and conference facilities
on several floors. Whether engaged
in research or involved in other departmental activities, faculty and students
can carry laptop computers equipped with wireless LAN adapters from room to room
and floor to floor while staying wirelessly connected to the network.
Because of the pilot study's success, the department has begun to expand
the wireless network. Plans are
being developed to design a wireless Wide Area Network (WAN) that will reach
from the department server to remote sites, including faculty members' homes.
A partnership between East Carolina University and Ericsson Wireless Internet
Solutions is targeting geographically displaced learners and mobile
professionals. This project
develops a high-speed wireless Internet system and an intelligent instructional
tool set for providing courses worldwide. It
will minimize learnerís need for a hardwire internet connection,
provide an intelligent instructional tool set and student assessment
system for pacing coursework to each studentís ability, and deliver multimedia
content without internet bandwidth limitations. Within three years, nine universities plan to implement
wireless solutions to deliver up to
40 credited hours.
Virginia Tech purchased four A-block Local Multipoint Distribution Services (LMDS)
licenses covering 16,500 square miles of rural Southwest Virginia and portions
of Tennessee and North Carolina to create a regional test bed for broadband
wireless technology. The licenses
give faculty and students the unique opportunity to do applied research in areas
such as LMDS signal propagation, systems and components, and antenna design.
Students can insert a wireless card into a laptop, turn on the machine,
and instantly connect to a network or the Internet.
This ease of access to the network encourages greater use of laptops and
greater integration of the technology into the curriculum.
Faculty members who have hesitated due to the physical effort of getting
a room of students online are more likely to consider assignments to use the
Internet. Ease of use also
encourages spontaneity in or out of the classroom.
Students and faculty can turn to their laptops to collaborate or answer
questions as soon as the need arises. Easy
and fast access and set up is valuable for groups of students.
Wireless technology can free up as much as an hour a day for students who
are using laptops at several different times each day.
Students and faculty can move from classroom to office or conference room
as they choose without logging on or off and rebooting their machines
A major goal of the research is to work with industry to accelerate the
development of the technology toward lower-cost components and to
support the technical and financial viability of LMDS in the rural
market. In addition to the research
value from the licenses, the University is supporting economic development by
providing its citizens and communities with early access to the emerging
technologies of LMDS.
In addition the system will be used to extend the stateís public ATM network,
so that broadband connectivity may be brought to more locations, especially as a
way to provide economical access to new network-based learning (www.aironet.com).
Advantages and Disadvantages
with any technology, there are both benefits and limitations.
Wireless communication is
not exception. Like many technological innovations before it
has rapidly advanced to the
point of users not questioning what can be done with wireless technology, but
rather what method to use and then how best to use the method chosen.
There are no wires from or
to any machine from anywhere, which is an advantage in
any environment. Wireless systems are commonly thought to be more
expensive initially than wired systems, but may actually be less expensive when
setting up a new system in an existing facility.
For example, in older buildings where cable access is not possible or is
to costly the relocation of wireless devices is simple and there are no
additional rewiring costs or
downtime with such a move. With
wireless access new devices can be
added or removed without disruption to the remaining system.
After the initial financial expenditure of setting up a wireless system,
the cost of running and maintaining a wireless communications solution is
minimal One problem with the
technology itself is the limited spectrum available for communications.
Splitting-up the environment into a number of small cells increases
overall accessible bandwidth of the communication system, but also increases the
cost as more cell sites are required.
Disadvantages of wireless systems are that they
slower than existing wireless technology which does not offer the
performance of wired systems. The generate sizeable radio waves, and can be
disrupted by interference. How much slower can depend on the tasks being done. There is little difference in simple tasks such as checking
e-mail and browsing the web. The
more complex tasks of downloading large files and using multimedia software, or
multi-tasking require more time on
wireless systems. While wireless
technology eliminates the need for a cord connecting the user to the network,
users still need to plug their laptops into an electrical outlet unless their
batteries are charged. Without
charged batteries, electrical wires remain (www.ccds.cincinnati.oh.us).
When a large number of devices are transmitting, a sizable amount of radio power
The effects of radio communication on human health are being examined,
but much more research is needed is this area.
Interfering signals generated by other devices in a business or education
environment, which can temporarily disrupt a communication link through the
Finally, the unconstrained nature of the communication medium of radio requires
the issue of network security to be addressed.
Verification of communication entities must
be performed to ensure that only registered devices may communicate using
the network, and that only registered devices receive the data.
Some form of encryption may be required for communications to avoid
interception of data transmitted by devices not officially taking part in the
Considerations in Wireless Technology
Being unwired offers
easy access to data, information,
and to the conducting of transactions. Being
unwired also presents greater
security risks than the wired world. The
WAP gateway is open to security
breaches. In other words, a breakpoint in the security of such a system occurs where
the wireless transport layer changes
to a secure socket layer to secure the connection between the WAP gateway and
the server. Verisign has deployed a
mini-certificate issuance service for WAP gateways. The certificates will support gateway assisted SSL and
gateway assisted object signing.
signatures can also be used in wireless devices.
The wireless client contains a private key and digital signing logic, but
does not need to store or process a certificate for the corresponding public
key. The certificate can be stored
in a directory within the wired infrastructure, and be picked up and used by
application servers whenever a userís digital signature needs to be verified.
This enables servers to use the same functions to verify digital
signatures from wireless clients as they use for verifying digital signatures
from wired clients (www.wapforum.org).
public infrastructure of key pairs
provides four requirements of electronic security (using cryptography, digital
signatures, and digital certificates): confidentiality, authentication,
integrity, and non-repudiation. These
key pairs are linked mathematically using asymmetric cryptography and each key
pair is unique. The originator of a
message uses the private key to digitally sign the message.
The digital signature is proof of that userís identity, the equivalent
of a legal, handwritten signature.
The recipient of the message verifies
the signature using the corresponding public key.
Because it is the only matching key, only it can verify the signature and
establish that the originator is authentic and the data is not altered (Sing,
2000). This technology enables
secure mobile transactions to all wireless applications.
Wireless communications are open to other potential security risks. An intruder
does not need physical access to the traditional wired network in order to gain
access to data communications. To
protect against any potential security issues, 802.11 wireless communications
have a function called WEP (Wired Equivalent Privacy), a form of encryption
providing privacy comparable to that of a traditional wired network.
If the wireless network has information that needs to be secure then WEP
needs to be used to ensure the data is protected at least at traditional wired
network levels. In addition, it
should be noted that traditional Virtual Private Networking (VPN) techniques
will work over wireless networks in the same way as they do over traditional
wired networks (Sing, 2000).
In summary, wireless technology has advanced rapidly since its inception.
this innovationís uses have expanded
communication systems producing exciting possibilities for applications
and implementations in corporate,
academic, and many other environments. It
will continue to be a challenge for
potentials users to remain current during such
rapid technological expansion.