11-12-2012, 01:10 PM
Wireless Local Area Network (WLAN) Advantages vs. Disadvantages
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Abstract
This paper addresses the Wireless Local Area Network (WLAN) for companies in European
countries. The wireless system for Local Area Network (LAN) is an important landmark in the
history of the Internet and electronic applications. It opens up existing systems, databases and
intranets to mobile equipment such as telephones and hand-held terminals through a graphical
customer interface. The most important benefit of WLAN is that it is independent of different
mobile technologies that are used in different parts of the world.
The recent increase in mobile computing technologies and projects in the enterprise
environment has resulted in extensive use of numerous point-to-point products that cover only a
small part of the total mobile and wireless infrastructure that is required.
This paper is intended to be used as a recommendation for any company involved in building
more effective use of commercial WLAN in European countries. Much of what is required to
build an enterprise WLAN standard has been already defined years ago. It is critical that this be
synthesized and summarized so that network managers and managements can have a better
understanding of how to manage this great WLAN technology in the commercial environment.
This paper attempts to fill in that space and concludes with an opinion of the WLAN technology
based on the research.
Introduction
Wireless LAN is a networking technology that allows the connection of computers without
any wires and cables, mostly using radio and infrared frequency (RF) technology. It's called
LAN because the range targets within an office, a building, a store, a small campus, or just a
house.
The description of a WLAN is a mobile data communication connectivity system installed
and configured as an alternative in some cases for traditional LAN. The WLAN equipment is
capable of receiving and sending data over an adequate range. In the United States, the WLAN
business is increasing in areas like the airports, health-care, warehousing and manufactures.
Several research companies are predicting a healthy increase in WLAN business market in the
coming years. The WLAN provides advantages over traditional LAN technology such as buried
cables in the ground, hidden cables behind walls, and long cable runs measured in feet or miles.
Without restrictions, the new technology infrastructure can easily be installed and ready to be
used.
Current growth concerning network communication technology in the enterprise
communication environment has resulted in widespread deployment of numerous products that
cover only a small part of the total mobile and WLAN infrastructure required. The WLAN
industry has experienced phenomenal increase over the past ten years. The U.S. wireless
industry posted revenue of $40 billion in 1999, according to the Cellular Telecommunications
Industry Association, and employed 156,000 workers (Palazzo, 2002). Most manufacturer
companies offer WLAN equipment to improve field productivity, increase customer approval
and reduce operational costs by shifting the way field workers and dispatchers perform their
jobs.
Mobility
The most important benefits of WLAN are flexibility, mobility and portability, but no
industry standard currently addresses the tracking or management of mobile equipment in its
Management Information Base (MIB). This omission would reject customers from roaming
between WLAN APs that cover a common work area, such as a complete floor of a building.
The manufacture has engineered this problem, offering its own solutions of flexibility algorithms
that facilitate roaming within an IP domain such as a floor with an eye towards optimizing
roaming across IP domains.
The WLAN equipment can provide customers with connectivity to real-time information
anywhere in their work areas. This flexibility supports productivity and service opportunities not
possible with traditional wired networks. Installation of WLAN equipment can be fast, easy and
can eliminate the need to pull cable through walls and ceilings.
Range
In the analysis of WLAN range, there is marginal theoretical difference in the range
capabilities of Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread
Spectrum (DSSS) systems. The largest range difference will be caused by two sources; the type
and location of the antenna system not the spread spectrum modulation used and the environment
that the equipment is operating in. The antenna diversity is one of the most important influences
on the range and performance of equipment, particularly near the edge of the range profile, the
marginal area. The antenna diversity is the use of multiple antennas that are physically
separated. This is done because the radio waves will reflect off all objects, walls, buildings,
bridges, cars, hills, trees, etc and cause nulls and peaks arbitrarily distributed in the air (OCBN,
2001).
It is significant for a good path to have a high height for the antenna. Basically, a better
antenna elevation means better connectivity range, with all other things being equal. An
appropriate antenna height would be required to “shoot over” path obstructions like hills or trees
and also to reach suitable “Fresnel” zone permission, see figure 5 on WLAN frequency & range.
This is much the same as the peaks and troughs that are seen on the surface of water when
separate waves encounter each other and are called "Multipath" in the radio environment. With
two antennas separated by a quarter of a wavelength, a few inches for 2.4 GHz band, it is
statistically very unlikely that both antennas will be in a null or wave trough at the same time,
whereas a single antenna will be realistically possible to be in a null in a highly reflective
environment, such as an office building (Proxim,1998).
Equipment Cost
An analysis reveals savings can be measured in terms of equipment cost for WLAN compared
to what customarily is in used for wired LAN connection. In order for two customers to
communicate over the wired network, the following are required for installation, network cable
installation with, data drop ($500), PC LAN card ($50), a hub ($100), small router ($2,500), a
network T1 modem ($1,300), and cable conduit between customer buildings, bringing the total to
$9,000. For the WLAN, connecting two customers to a LAN, the total cost is not more than
$7,000 that to include the bridge 100Mw output ($1,400), ceiling antenna ($82.00), 11Mbps
DSSS AP ($990) and cable ($120). The big savings is that there is no need to open a trench to
bury network cable.