WIRELESS
NETWORKS (EC8004)
Dr. B.VENKATALAKSHMI
https://www.linkedin.com/in/dr-b-venkatalakshmi-79a7a013/
COURSE
DESCRIPTION
01
Name of the Course:
WIRELESS NETWORKS
02
Course Code : EC8004
03
Course Category :
Professional Elective(PE)
04
Prerequisite: Communication
05
Credits: 3
Networks(PC)
Why do we learn this
course?
02
01
For core
companies
(Qualcomm,
Sasken,
STMicroelectron
ics, Cyprus
semiconductors,
Infineon, Cisco)
placement
For Tech Dream Jobs
like Application
Engineer, Process
Engineer, Production
engineer etc.,
https://www.infineon.co
m/cms/en/careers/worki
ng-atinfineon/applicationengineer/
03
To enrich our
domain skill
competency for
competitive
exams/Higher
Studies/ Research
opportunities
03
03
What capability will be obtained after learning this course?
COs
You can simply impress your
audience and add a unique zing
and appeal to your Presentations.
CO3
CO1
Conversant/ Comprehend the
latest 3G/4G networks and its
architecture.
Implement different type of
applications for smart phones and
mobile devices with latest network
strategies
CO4
CO2
Design and implement wireless
network environment for any
application using latest wireless
protocols and standards.
How do we obtain above capabilities?
UNIT I
UNIT I – MIND MAP
WLAN FUNDAMENTALS
WIRED Vs WIRELESS
WLAN FUNDAMENTALS
WLAN stands for Wireless Local Area Networks. These are networks
connecting end user devices using tether less communication within
a home, office or small buildings.
WLAN FUNDAMENTALS
The goal of WLAN is to replace office cabling and to
provide tether less connection
WLAN advantages
•Flexibility High penetration across walls, effective
communication being RF waves in the coverage area
•Planning  Needs less planning as wiring is not
required
•Design  Tiny and PDAs are possible
•Robustness  Resilience under disaster
•Cost After initial establishment, scalability incurs less
cost, so overall cost is less
WLANs disadvantages
•Poor Quality of Service
Description
Bandwidth
WLAN
10mbps
Error rate
Delay
10-4
More
Others
Cu – 100mbps
Optical – 1000mbps
Optical- 10-12
Less
Remarks
LOW
HIGH
Due to error detection
and
correction
mechanisms
•Proprietary Solutions
Slow standardization procedures – additional features compatibility – need for
adapters from same vendors
•Restrictions
Need for global solution establishment – like IMT-2000- WLAN needs low
power devices and license free frequency bands
•Safety and security
Eavesdropping becomes more easy – precaution to prevent safety hazards
Design Goals of WLAN
•Global Operation
•Low Power
•License free operation
•Robust Transmission Technology
•Simple cooperative operation
•Easy to Use
Transmission Techniques - WLAN
Infrared Technology uses infrared light of 900nm wavelength. This technology can support for setting up Ad-hoc
connections and mobility feature within small area. IR uses directed light if there exists Line Of Sight (LOS) between
sender and receiver. Senders are simple LEDs or LASER and receivers are Photo Detectors. It uses IrDA (Infra Red
Data Association) protocol. The advantages of IR technology are
•Simple and cheap senders and receivers
•IrDA 1.1 supports dual data rate 1.15 and 4Mbps
•No license
•Shielding is simple
•No electrical interference
IR technology also has disadvantages like low bandwidth and lack of penetration through walls and obstacles.
Transmission Techniques - WLAN
•RF Transmission makes use of RF waves for data transmission. Many varieties of wireless
networks are supported by RF transmission. There are many advantages of RF transmission as
follows
•Wide Area Networks, Mobile Networks are all supported by RF transmission
•Large area can be covered
•Can penetrate through walls and other obstacles easily
•Reflection supports more coverage
•No need for LOS
•Higher data rate – 54Mbps
The major disadvantage of RF transmission technology is Shielding issue. Its very difficult to
provide shielding. Electrical interference is unavoidable
Infrastructure WLAN
Ad-hoc WLAN
Infrastructure WLAN
•Provides access to other networks
•Do forwarding and Medium access control functionalities
•Backbone/fixed network connectivity is established through access points
•Several access points along with fixed networks form larger network (beyond RF
coverage)
•Design becomes simple as only the access point need to be configured and not
the client nodes
•Can use different access schemes with or without collision
•Disadvantage – cannot be used for disaster management
•Example – Cellular networks, Satellite phone network (Fully wireless)
Ad-hoc WLAN
ACCESS CONTROL
How a wireless host can get access to the shared
medium (air)
The CSMA/CD algorithm does not work in wireless
LANs for such reasons:
- Send and receiving signal power
- The hidden station problem prevents collision
detection
HIDDEN STATION PROBLEM