4. INTRODUCTION TO
WI-FI
WIFI stands for wireless fidelity
Brand licensed by the Wi-Fi Alliance
Based on IEEE 802.11a,b and g standards
Early 1980s, 1st wireless system was developed
After 1990, wireless technologies gradually widely
accepted
Wi-Fi is a local area network technology that was
originally thought to replace the thousands of miles of
LAN cables
5. CONT…
WIFI is considered to be one of the first widely
deployed fixed broadband wireless networks.
The Wi-Fi architecture consists of a base station that
wireless hosts connect to in order to access network
resources.
As long as the users remain within 300 feet of the
fixed wireless access point, they can maintain
broadband wireless connectivity.
6. ORIGIN OF WI-FI
The precursor to Wi-Fi was invented in 1991 by NCR
Corporation in Nieuwegein, Netherland.
The first wireless products were brought on the market under
the name WaveLAN with a speeds of 1 MB to 2 MB.
Vic Hayes has been named as father of “Wi-Fi’’.
8. WHAT A WIRELESS NETWORK
MADE UP OF:
Base stations, Access points, or Gateways
The base station sends and receives radio signals to
and from the Wi-Fi radio in your laptop or PC.
Enabling you to share your Internet connection with
other users on the network.
Access points and gateways have a wide range of
features and performance capabilities, but they all
provide this basic network connection service.
9. TYPICAL COMMUNITY WI-FI
CONSTITUENTS
High gain Parabolic grid antennas
to beam the signal to over 30km
from tower to tower
Sector antennas to beam the signal
from the towers to the community
users
Customer Premises equipment
(CPE) to access the signal from the
towers
Other components that need to be
installed in order to put the above
systems together
10. WIFI
STANDARDS
Standard Throughput Range Frequency
802.11a Up to 54 Mbps Up to 300 ft Between 5
and 6 Ghz
802.11b Up to 11 Mbps Up to 300 ft 2.4 Ghz
802.11g Up to 54 Mbps Up to 300 ft 2.4 Ghz
11. STRENGTHS OF
WI-FI
Does not require regulatory approval for individual.
Wi-Fi allows local area network to deployed without wires
for client devices
Wi-Fi can make access publicly available at Wi-Fi
hotspots.
Users are able to be mobile for up to 300 feet from the
access point.
There are many Wi-Fi compatible products that are available
at a low cost and can interoperate with other network
technologies.
12. WEAKNESSES OF WI-
FI
Designed technically for short-range operations
and basically an indoor technology
Low bandwidth compared to wired networks
Limited level of mobility
Susceptible to interference
Security is a concern
13. WIMAX
WIMAX stands for Worldwide Interoperability for
Microwave Access
The technology is specified by IEEE as 802.16 standard.
It is a standards-based technology enabling the delivery of
last mile wireless broadband access as an alternative to
cable and DSL.
WIMAX is expected to provide fixed, nomadic,
portable and eventually, mobile wireless broadband
connectivity without the need for direct line-of-
sight (LOS) with a base station.
14. CONT…
In a typical cell radius deployment of three to ten
kilometers, WIMAX Forum Certified™ systems can
be expected to deliver capacity of up to 40 Mbps per
channel, for fixed and portable access applications.
Goal: Provide high-speed Internet access to home and
business subscribers, without wires.
Mobile network deployments are expected to
provide up to 15 Mbps of capacity within a typical
cell radius deployment of up to three kilometers.
16. REFERENCE
MODEL
Application Application
Transport Transport
Network Network Network Network
Data Link Data Link Data Link Data Link
Physical Physical Physical Physical
Radio Medium
17. WIMAX
STANDARDS
802.16 802.16a 802.16- 802.16e-
2004 2005
Date December January June December
Completed 2001 2003 2004 2005
Spectrum 10-66 GHz < 11 GHz < 11 GHz < 6 GHz
Operation LOS Non-LOS Non-LOS Non-LOS and
Mobile
Bit Rate 32-134 Mbps Up to 75 Up to 75 Up to 15
Mbps Mbps Mbps
Cell 1-3 miles 3-5 miles 3-5 miles 1-3 miles
Radius
20. STRENGTHS OF
WIMAX
Faster than broadband service
Single station can serve hundreds of users
No more DSL installation fees
Much faster deployment of new users comparing to wired
networks.
Would allow gamers access to ad hoc local networks of
other players with the same gear- without any internet
connection.
WIMAX services are available in the rural area too
21. WEAKNESSES OF
WIMAX
Line of sight is needed for longer connections.
Weather conditions like rain could interrupt the signal.
Big installation and operational cost which makes it
expensive.
Bandwidth Shared Among Users
WIMAX network is very heavy in structure therefore need
much electrical support for running the overall network.
Speed Decrease over Large Distance
When compared to other modes of broadband connectivity,
for example, fiber optic cables and satellite internet,
WIMAX is still slow