Caleb Howell
ECE 4007 – RP1 – Dr. Jong-Man Kim
RFID Cartographers
Wireless Fidelity Communication Standards
Introduction
Becoming more standard as computer communication technology develops,
Wireless Local Area Networks (WLAN) may very well be the primary embodiment of all
networks in the near future. WLAN technology has been advancing since its conception,
and the standards by which wireless technology manufacturers adhere is IEEE 802.11.
This paper covers various commercial uses, underlying technology, and the assorted
components needed to implement the IEEE 802.11 WLAN standards.
Commercial Applications of IEEE 802.11 Standards
Any wireless networking client’s location that can “see” a wireless access point
can gain access to that particular network. Examples of these locations include, but are
not limited to, businesses and other contained organizations, waiting rooms, coffee shops,
and restaurants. Every one of the aforementioned locations implements IEEE 802.11
technology standards. In June 2008, major U.S. wireless communication companies
including IBM, Intel, AT and T Wireless Services, and Verizon Communications
disclosed that they are planning to start a company, currently code-named Project
Rainbow, that will provide business travelers with national Wi-Fi service. Additional
providers who sell their services for customers who use wireless access points across the
United States include Boingo Wireless Inc., iPass Inc., and Sputnik Inc. [1].
Underlying Technology of IEEE 802.11 Standards
Currently Used Technology
The 802.11 standard has many amendments. Three of those amendments include
802.11 a,b, and g. 802.11a operates in the frequency range of 5.1 to 5.8 GHz and
transmits up to 54 Mbps. The 802.11b operates in the range of 2.4 to 2.485 GHz and
transmits up to 11 Mbps. Finally, the 802.11g standard operates between the frequencies
2.4 and 2.485 GHz and transmits up to 54 Mbps [2, pp. 513-514]. The higher operating
frequency of 802.11a shortens its transmission distance for a given power level and is
easily obstructed, but it transmits at a very high rate. In contrast, 802.11b operates at a
lower frequency allowing it to transmit a greater distance than 802.11a and more easily
penetrate walls, but its transmitting rate is lower. 802.11g is basically a combination of
802.11a and 802.11b. Its operating frequency is lower hence a greater transmission
distance, and its rate of data transmission is extremely fast. The only drawbacks of
802.11g are that, like 802.11b, appliances can interfere with the signal because of the
frequency range, and 802.11g costs more to implement than the other two [3]. All three
of the standards share many characteristics and all use the same medium access protocol,
CSMA/CA. Additionally, they all have the ability to extend to greater distances by
reducing their transmission rate [2, pp. 513-514].
There are eight total finalized amendments to the 802.11 standard. On March 8,
2007, all eight amendments were combined into one document. It is called IEEE 802.112007 and is the single most modern official document available that contains all
amendments to the 802.11 wireless communication standard [4].
Upcoming Technology
The newest version of the 802.11 series is the 802.11n. This new standard
increases the wireless network data transmission rate to over 100 Mbps, because it
implements the new MIMO technology which uses multiple wireless signals and
antennas instead of one [5]. By way of increased signal intensity, 802.11n also transmits
a greater distance than previous standards. The drawbacks of 802.11n are that 802.11b/g
based networks may be subject to interference from the multiple signals that 802.11n
uses, n technology costs more than the other standards, and the standard is not finalized.
An example in the differing costs of n and g notebook card technology sold by Belkin is
$70 and $35 respectively, where n is double the price of g [6].
IEEE 802.11 Implementation
When implementing the IEEE 802.11 standard, both software and hardware are
requirements for functionality. The architecture for 802.11 is comprised of one or more
basic service sets (BSSs). Each BSS contains a central base station, frequently called an
access point, and one or more wireless stations or clients. All BSSs are connected to a
single interconnection device, for example, a router [2, p. 514].
The software aspect of IEEE 802.11 implementation includes a multiple access
protocol (MAC). A wireless client can begin sending and receiving data frames to and
from the access point once it has associated itself with that access point, but problems can
arise when multiple clients attempt transmitting data frames simultaneously over the
same channel. This is where the MAC is implemented in coordinating the transmissions.
The most commonly used MAC in wireless networks is called carrier sense multiple
access with collision avoidance (CSMA/CA) [2, p. 517].
As previously mentioned, 802.11n, once standardization is complete, is supposed
to achieve a transmission rate of 100 Mbps. Two theories are implemented to achieve
that goal: improve MAC efficiency, and increase the peak data rate well beyond 100
Mbps. Much of this is accomplished by MIMO technology which boosts the data rate
through parallel antenna transmission of multiple spatial streams [7].
[1]
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[Accessed Aug. 31, 2008]
[2]
J. F. Kurose and K. W. Ross, Computer Networking: A top-down approach
featuring the internet, 3rd ed. Boston, MA: Addison Wesley, 2005, pp. 513-528.
[3]
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[Accessed: Sept. 2, 2008]
[4]
IEEE Standard for Information Technology-Telecommunications and information
exchange between systems-Local and metropolitan area networks-Specific
requirements - Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications, IEEE Standard 802.11-2007, June 12, 2007.
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[Accessed: Sept. 1, 2008]
[7]
J. Lorincz and D. Bequsic, “Physical Layer Analysis Emerging IEEE 802.11n
WLAN Standard,” presented at the 8th Int. Conf., FESB-Split, Split Univ.,
Croatia, Feb. 20-22, 2006.