Basic Concepts in Wireless LAN

1. Shashikant V. Athawale
Assistant Professor
Department of Computer Engineering,
AISSMS COE ,Pune

2.  Wireless Standard
 Wireless LAN And Technology
 Wireless Application Protocol

3.  There have been 5 major milestones in wireless internet
communication.
◦ 802.11 – Released in 1997, the original wireless protocol
◦ 802.11a – Released in late 1999
◦ 802.11b – Released in late 1999
◦ 802.11g – Released in mid 2003
◦ 802.11n – Released in 2009

4.  The ORIGINAL wireless protocol.
◦ Security implemented via WEP
 Wired Equivalent Privacy (Legacy)
 Provided Bandwidth
◦ 1 or 2 Mbit/s due to use of CSMA/CA
 Relatively Unpopular
 Low interoperability due to loose specifications
 Used DSSS
 Considered Legacy and no longer used

5.  One of two amendments to the original 802.11
specification released simultaneously
 Provided up to 54 Mbit/s bandwidth
 Uses OFDM
◦ Orthogonal Frequency-Division Multiplexing
 Transmits a signal over several sub signals for higher efficiency

6.  Second of two amendments released in 1999
 Provided up to 11 Mbit/s bandwidth
 Uses DSSS
◦ Direct-Sequence Spread Spectrum
 Transmits a signal over several sub signals for higher efficiency

7.  Pretty much the most common wireless network in use
today.
 Operates on 2.4Ghz band
 Provides up 54Mbit/s bandwidth
◦ 108Mbit/s with special implementations
 Uses OFDM for modulation
 Adopted quickly after release for cheap and high bandwidth

8.  Newest member of the 802.11 family.
 Has rated 600Mbit/s bandwidth
 Introduces MIMO
◦ Multiple-Input Multiple-Output
 OFDM Modulation
◦ Uses higher frequencies for increased number of carrier waves

9.  A wireless LAN uses wireless transmission medium
 Used to have high prices, low data rates, occupational
safety concerns, and licensing requirements
 Problems have been addressed
 Popularity of wireless LANs has grown rapidly.

10.  Saves installation of LAN cabling
 Eases relocation and other modifications to network structure
 However, increasing reliance on twisted pair cabling for LANs
◦ Most older buildings already wired with Cat 3 cable
◦ Newer buildings are prewired with Cat 5
 Wireless LAN to replace wired LANs has not happened
 In some environments, role for the wireless LAN
◦ Buildings with large open areas
 Manufacturing plants, stock exchange trading floors, warehouses
 Historical buildings
 Small offices where wired LANs not economical
 May also have wired LAN
◦ Servers and stationary workstations

14.  Peer-to-peer network
 Set up temporarily to meet some immediate need
 E.g. group of employees, each with laptop or palmtop,
in business or classroom meeting
 Network for duration of meeting

16.  Same as any LAN: High capacity, short distances, full connectivity, broadcast
capability.
 Throughput: efficient use wireless medium
 Number of nodes:Hundreds of nodes across multiple cells
 Connection to backbone LAN: Use control modules to connect to both types of
LANs
 Service area: 100 to 300 m
 Low power consumption:Need long battery life on mobile stations
 Transmission robustness and security:Interference prone and easily
eavesdropped
 Collocated network operation:Two or more wireless LANs in same area
 License-free operation
 Handoff/roaming: Move from one cell to another
 Dynamic configuration: Addition, deletion, and relocation of end systems
without disruption to users

17.  Infrared (IR) LANs: Individual cell of IR LAN limited
to single room
◦ IR light does not penetrate opaque walls
 Spread spectrum LANs: Mostly operate in ISM
(industrial, scientific, and medical) bands
◦ No Federal Communications Commission (FCC) licensing is
required in USA
 Narrowband microwave: Microwave frequencies but
not use spread spectrum
◦ Some require FCC licensing

18.  An open, global specification that empowers mobile
users with wireless devices to easily access and interact
with internet information and services instantly.
 The wireless industry came up with the idea of WAP.
The point of this standard was to show internet contents
on wireless clients, like mobile phones.

19.  WAP is an application communication protocol
 WAP is used to access services and information
 WAP is inherited from Internet standards
 WAP is for handheld devices such as mobile phones
 WAP is a protocol designed for micro browsers
 WAP enables the creating of web applications for
mobile devices.
 WAP uses the mark-up language WML (not HTML)
WML is defined as an XML 1.0 application

20.  To enable easy, fast delivery of relevant information and services
to mobile users.
 Type of devices that use WAP
 Handheld digital wireless devices such as mobile phones, pagers,
two-way radios, smart phones and communicators -- from low-
end to high-end.
 WAP works with most Wireless networks such as:
CDPD, CDMA, GSM, PDC, PHS, TDMA, FLEX, ReFLEX,
TETRA, DECT, DataTAC, Mobitex.

21.  Leverage existing standards whenever possible
 Define a layered, scalable and extensible architecture
 Support as many wireless networks as possible
 Optimize for narrow-band bearers with high latency
 Optimize for efficient use of device resources
 Provide support for secure applications and
communication

22.  WWW programming model is optimized and extended
to match characteristics of the wireless environment
 Utilizes proxy technology to connect between the
wireless domain and WWW

25.  WAP Device
- Is used to access WAP applications and content. It might be a
PDA, handheld computer.
 WAP Client
- Entity that receives content from Internet via a WAP Gateway.
This is usually the WAP Browser.
 WAP Content/Origin/Application Server
- Element in the network where the information or web/WAP
applications resides.

26. Web
Server
Wireless
Network
WAP
Proxy
HTML
Filter
WTA
Server
WAP
Client
WML
WML
HTML

27. Other Services
And Applications
Transport Layer (WDP)
Security Layer (WTLS)
Transaction Layer (WTP)
Session Layer (WSP)
Application Layer (WAE)
GSM CDMA PHS IS-136 CDPD PDC-P FLEX Etc…

28.  General-purpose application environment based on a combination of
WWW and mobile telephony technologies.
 It defines the user interface on the phone. It contains WML and
WTA (Wireless Telephony Application).
 Primary objective – interoperable environment.
 WAE includes a micro-browser (Client software designed to
overcome challenges of mobile handheld devices that enables
wireless access to services such as Internet information in
combination with a suitable network) server environment which
provides
◦ WML
◦ WML script
◦ WTA
◦ Content formats

29. • WAP provides a markup language and a transport protocol that
open the possibilities of the wireless environment and give players
from all levels of the industry the opportunity to access an untapped
market that is still in its infancy.
• The bearer-independent nature of WAP has proved to be a long-
awaited breath of fresh air for an industry riddled with multiple
proprietary standards that have suffocated the advent of a new wave
of mobile-Internet communications. WAP is an enabling technology
that, through gateway infrastructure deployed in mobile operator's
network, will bridge the gap between the mobile world and the
Internet, bringing sophisticated solutions to mobile users,
independent of the bearer and network.
• Backed by 75 percent of the companies behind the world's mobile
telephone market and the huge development potential of WAP, the
future for WAP looks bright.

30.  http://en.wikipedia.org/wiki/IEEE_802.11
 http://www.cisco.com/en/US/prod/collateral/wireless/ps
5678/ps6973/ps8382/prod_white_paper0900aecd806b8
ce7_ns767_Networking_Solutions_White_Paper.html
 www.palopt.com.au/wap

31.  Books
◦ Mobile communications: Jochen Schiller, Addison Wesley 2000
◦ Understanding WAP:
 Official Website (specifications)
◦ www.wapforum.org
 Technical/Developer Info and tools
◦ www.palopt.com.au/wap
◦ www.wap.net
 Major players
◦ www.nokia.com/wap
◦ www.ericsson.se/wap
◦ phone.com
 OpenSource effort
◦ www.wapgateway.org (Kannel WAP gateway project)

32. THANK YOU…!!!