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Wireless
Internet
By Matt Hyclak
Wireless Internet
is actually a group of technologies, some old and some new, that
allow users to connect to a network without any physical cabling.
The most common method of connecting up today is via Wireless
Fidelity (Wi-Fi), the marketing term for the Institute of Electrical
and Electronics Engineers’ (IEEE) 802.11 standard. There
are actually several sub-types of these standards. The first to
market was 802.11b, followed shortly by the arrival of 802.11a
and 802.11g.
How
does IP-Wireless Work?
802.11b
works in the unlicensed 2.4GHz radio spectrum, allowing for 11Mbps
data rates. Connection distances on the order of 100 feet are
typical for this technology. 802.11a is positioned for the higher
5GHz band, and can provide speeds up to 54Mbps. Meanwhile, in
a quick follow-on to the other two 802.11g has been approved by
the Institute of Electrical and Electronics Engineering standards
group as an additional format. It also operates in the 2.4GHz
spectrum, and is compatible with 802.11b, but 802.11g provides
for 54Mbps speeds (IEEE 2004).
Two additional 802.11 standards, 802.11e and 802.11i, are currently
being examined. 802.11e adds Quality of Service (QoS) to the standard
while maintaining backward compatibility. QoS is especially important
as Voice over IP gains popularity, to ensure that the voice traffic
is delivered in a timely a manner when other data is on the network.
802.11i adds the Advanced Encryption Standard (AES) security protocol
to the 802.11 family as Wi-Fi Protected Access (WPA) version 2,
providing much more security than is available via the current
Wired Equivalent Privacy (WEP) or WPA implementations.
These new standards fill an important hole for businesses to feel
comfortable deploying wireless technologies. According to a 2004
study conducted by Jupiter Research, “90% of the 313 companies
surveyed say improved security solutions will impact their decision
to install WLANs this year.” (Le Thomas, 30).
The IEEE Wireless LAN working group began accepting proposals
in September 2004 for the 802.11n standard. 802.11n will double
the current bandwidth of the 802.11 family from 20MHz to 40MHz,
and is “shooting for a data rate of 250Mbps with an actual
throughput of about 175Mbps.” (Rupley, 21) This high rate
of transmission speed will depend on Multiple-Input Multiple-Output
(MIMO) antenna technology, that locates multiple antennas in a
device to increase the amount of available bandwidth by using
several channels. (Network World Fusion, 2004)
In addition to the Wi-Fi family of standards, an additional wireless
standard is emerging: WirelessMAN. Worldwide Interoperability
for Microwave Access (WiMax) is a term coined by the non-profit
WiMax Forum, a group made up of industry leaders in the technology.
WiMax is defined in the IEEE’s 802.16 standard. 802.16 is
not seen as a competitor to the existing Wi-Fi infrastructure,
but as a compliment to it. The 802.11 family of protocols is designed
to replace the Local Area Network (LAN). Since LANs generally
cover small areas geographically, 802.11 can use the unlicensed
frequencies at low power. In comparison, WiMax is designed for
Metropolitan Area Networks (MAN), requiring higher power. The
standard designates that higher frequencies between 10GHz and
66GHz be used.
The 802.16a standard was approved in January 2003. It positions
user applications in a range of frequencies from 2-11GHz spectrum
with special attention to non-line-of-site situations. 802.16a
can offer speeds of 70Mbps at distances of about 30 miles. This
is obviously a much larger area of coverage than what Wi-Fi provides.
Currently, the 802.16 standard is only for fixed wireless transmission.
The 802.16e standard under discussion adds extensions for mobile
wireless technology. (IEEE 2004)
The
Background and Promotion
Both
the 802.11 and 802.16 standards were developed by the IEEE; however,
input from industry players can affect what features and specifications
are included in the standards. Good examples of this are the 802.11n
standard in which the IEEE solicited proposals to help define
the standard. The WiMax industry group formed around the 802.16
standard, which includes manufacturers such as Intel, Motorola
and AT&T. Since the standards have gone through the IEEE,
the playing field is fairly level for competitors, ensuring that
end-users will have compatible equipment, regardless of which
manufacturer(s) are chosen.
What
Problems do 802.11 and 802.16 Solve?
802.11
and 802.16 are similar, but solve slightly different problems.
802.11 is very much focused on LAN technology, generally as a
replacement or compliment to an existing Ethernet network. 802.11
is very well suited to covering buildings with a handful of access
points, requiring very few wires to be run to connect to the network.
This is especially useful in situations where pulling cable is
difficult, costly, or even impossible in a case such as a historical
building. It also has a large consumer following since a family
can now put computers in different rooms and not have to worry
about trying to run cable or hiring someone to do it (See ).
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Figure
1 – Source: http://www.homeofficereports.com/homenetworks.htm |
802.11
is also useful for situations where unknown
computers will be coming in and out of the network. Coffee
shops and similar locations with “wireless hotspots”
are good examples. Providing everyone with an Ethernet port is
difficult when it is unknown how many people will need access,
with what types of equipment, and exactly where in the building
it will be needed. Covering the area with wireless eliminates
that problem.
802.16 solves a different set of problems. As it exists now, it
is a Point-to-Multi-Point fixed wireless technology. With the
802.16a standards, line-of-sight is not needed to communicate
with the access points. This is particularly useful when trying
to deliver service to an area where terrain makes running cable
too costly or infeasible and traditional wireless standards will
not work. The coverage territory could be a mountainous region
or a dense city with many tall buildings.
Interconnection
with Other Media
802.11
and 802.16 technologies work in the microwave spectrum, that works
well with self-contained networks. Internet users can use the
wireless technology to reach other networks such as the Internet
or a business or home LAN. This connection can be made through
fiber optic cable, twisted pair Category 5 or Category 6 cable,
or even coaxial cable. The point is, eventually, a cable is needed.
The Wireless Access Point (WAP) provides an appropriate interface
into the wired network, whatever that may be. Since 802.11 is
a technology that is extremely dependent on Ethernet, that is
usually a standard RJ-45 twisted pair interface for 10, 100 or
even 1000Mbps Ethernet. (IEEE, 2004) In the case of 802.16, Ethernet
and fiber optic interfaces are likely to be used.
Economic and Regulatory Constraints
802.11
is not a heavily regulated technology. Since families will tend
to use the unlicensed spectrum in the 2.4GHz and 5GHz range, there
is no real regulation on their use. So long as the devices are
sufficiently low-powered to not interfere with the users operating
in the licensed spectrum, the FCC in the United States and similar
bodies worldwide see little need to impose restrictions.
Economics has also become a non-factor to consumers for 802.11.
The hardware is cheap enough now that it is easily affordable
by anyone who owns a computer. Wireless Access Points cost between
$50-100, and the interface cards for the computers are less than
$50. For a larger installation such as a coffee shop or airport,
there will be some expenditure to map the area to ensure coverage
is satisfactory to users. Equipment that has central management
capabilities is slightly more expensive, but not unreasonably
so.
802.16 will be more highly regulated since it uses spectrum that
is licensed. The areas that can be covered by 802.16 are much
larger, about half the distance FM radio stations and TV stations
can broadcast. This application begs for oversight to ensure that
interference is not an issue in overlapping areas. Economic effects
remain to be seen. Intel is just now releasing chips that implement
the 802.16 standard. Since it is such a new technology, there
will be a fairly high cost associated with the new equipment,
quite the opposite of the commodity 802.11 hardware.
Applications
802.11 technologies are meant to supplement or replace wired LAN
technologies. The coverage area of a single Wireless Access Point
inside buildings is approximately a 100 foot radius, so several
access points are needed for full coverage. Open areas can also
be covered with well-designed antenna placement, usually requiring
fewer WAPs. Currently, the biggest application for this technology
is Internet access.
With the new 802.11e standard, featuring Quality of Service, devices
such as Cisco System’s 7920 Wireless VoIP phone will become
much more useful. The concept of a phone at one’s desk will
be obsolete since the phone can be carried around and calls completed
so long as the user is in an area covered by wireless. The phone
number remains the same regardless of where that user is. This
type of technology will get increased use as broadband becomes
more common in the home and the wireless equipment becomes less
costly.
Already the “standard” wireless devices are extremely
cheap; it will not be long before the 802.11e and 802.11i standards
can be completed for the same cost. Wireless “hot spots”
are becoming more common in coffee shops and book-stores where
proprietors are looking for ways to keep customers longer, thus
encouraging them to purchase more. Airports and hotels are also
deploying wireless networks that can be used, often for a fee,
by those in public areas.
The first applications of 802.16 will be in the backhaul of data.
“There's a clear application for WiMax as a backhaul technology…to
extend our current architecture.” (Nobel, 23) Instead of
running a cable 80 miles from Athens to Columbus OH, three or
four towers could be erected for point to point relay of the data,
eliminating the need for right-of-way and burying or hanging cable,
possibly at the cost of some speed. The economic benefits could
be enough to warrant that speed difference. Since 802.16a is not
line-of-sight dependent, aggregating traffic and transmitting
it over that wireless technology can be used in many locations
where wire line or line-of-sight is prohibitive.
Another application will be offerings of T1-like speeds (1.544Mbps)
to small businesses or residences. WiMax will be able to take
the place of cable modem and DSL services (Lawson, 20). A single
802.16 tower can handle on the order of 50 T1s, which can be very
appealing financially. As the 802.16e standard is implemented,
the concept of a LAN can be applied to much larger areas and mobility
will be possible.
The 802.11-enabled Wireless IP phones can now become 802.16-enabled,
allowing use in a much larger area. Competition to the cell phone
industry is a significant possibility. With 70 Mbps of bandwidth
available, over 1,000 standard telephone calls can be handled
on a single tower. Data services can be offered as well, possibly
with speeds in the Mbps range as opposed to the few hundred Kbps
available now with the current generation of advanced cell phones.
Merging the two technologies into a single handheld device could
allow for wireless calling from anywhere (including home, car
and office), data services (such as calendars, contacts and email),
online gaming, and many other features that would transparently
shift between 802.16 towers and 802.11 access points. It is expected
that “WiMax capability would be available in laptops by
2006, followed by handsets in 2007” (IEEE, 14). The hybrid
Wi-Fi/WiMax service could possibly be the “killer app”
that encourages the deployment of wireless on a grander scale.
Conclusion
Wireless is here to stay. Deployment will mostly focus on convenience
(access on home networks, as well as in coffee shops) and areas
where wire line is prohibitively expensive or impossible to implement
(mountains, many islands as in Malaysia). For high bandwidth applications,
cable will still be the preferred solution, especially with the
bandwidth available in fiber optics.
Wireless can provide both fixed and mobile access. With large
coverage by 802.16 and local coverage by 802.11, devices will
soon be manufactured to implement both technologies so that they
can be used anywhere. This will insure a future for wireless for
a long time to come.Brain, Marshall. 2004. How Wi-Fi Works [online].
Cited October 6, 2004. Available from World Wide Web: (http://computer.howstuffworks.com/wireless-network.htm)
References
Cohen,
Alan. “WiMax: The Wireless Net Gets Extreme”. PC Magazine
(July 2004): 107.
IEEE. 2004. “Intel Joins Siemens in WiMax Drive”.
IEEE Review (March 31, 2004): 14.
IEEE. 2004. IEEE 802 Standard [online]. Cited October 6, 2004.
Available from World Wide Web: (http://www.ieee.org/portal/index.jsp?pageID=corp_level1
&path=about/802std&file=index.xml&xsl=generic.xsl#802_11gen)
Lawson, Stephen. “Intel Unveils First WiMax Silicon”.
Infoworld (September 13, 2004): 20.
Le Thomas, Nguyet. “Can Wi-Fi Live Up to Enterprise”.
America’s Network (July 15, 2004): 30-31.
Network World Fusion. MIMO (multiple-input multiple-output) [online].
Cited December 20, 2004. Available from World Wide Web: (http://www.nwfusion.com/details/6830.html).
Nobel, Carmen. “Airespace's Mission: Lead Wireless Access
Pack”. eWeek (August 2, 2004): 23.
Rupley, Sebastian. “Next-Gen Wi-Fi”. PC Magazine (October
5, 2004): 21.
WiMax Forum. 2004. Certification [online]. Cited October 6, 2004.
Available from World Wide Web: (http://www.wimaxforum.org/certification)
Yang, Catherine, Green, Heather. “Welcome to Broadband City”.
BusinessWeek 10/4/2004. Available from Academic Search Premier.
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