Wireless LANs (WLANs) allow computers to connect to a local network using radio transmissions rather than wires. They use technologies like Wi-Fi that transmit data over the 2.4 GHz or 5 GHz radio bands. WLANs provide mobility within a limited range and can be used to avoid installing network cables. However, they have less range than wired networks and can experience interference from other devices.

1. Submitted to :
Mr. Tarun Verma
Submitted by :
Sagar Bissa(2011uec1298)
Ramniwas Jat (2011uec1296)
Sandeep Kr. Mahawar(2011uec1303)
Rakesh Mehra(2011uec1293)
Sitaram Choudhary(2011uec1312)

2. Outline
• Communication Systems
• Wireless Communications
• Radio
• Radar
• History of wireless communication
• Current Wireless Systems
• Cellular systems
• Wireless LANs
• Satellite Systems
• Paging Systems
• Bluetooth
• Sixth sense Technology
• Design challenges

3. COMMUNICATION SYSTEMS
• Provide electronic exchange of multimedia data,
Voice, data, video, music, email, web pages, etc.
• Communication Systems of today Radio and TV
broadcasting, Public Switched Telephone Network
(voice, fax, modem)
• Cellular Phones
• Computer networks (LANs, WANs, and the
Internet)
• Satellite systems (pagers, voice/data, movie
broadcasts)
• Bluetooth

4. Block diagram of a Communication Systems
Transmitter
Carrier
Information to
be transmitted
(Baseband signal)
Transmitted
signal
Channel
Received
signal
Receiver
Recovery of
information

5. Objectives
• Provide electronic exchange of multimedia
information
• The information to be transmitted is electromagnetic
wave or electrical signal may represent: multimedia
data, Voice, data, video, music, email, web pages, etc.
• The frequency bandwidth occupied by the
information signal is called the baseband, and the
signal is often referred to as the baseband signal.
• Channel – is the medium by which the transmitted
signal is propagated:
• Various layers of atmosphere, cable for telephone or
date link, cable TV or
• Electrical signals are converted to a corresponding
light signal that is propagated through a fiber optic
channel

6. What is Wireless Communication ?
 Transmitting voice and data using electromagnetic
waves in open space (atmosphere)
Electromagnetic wave
Travel at speed of light (c = 3x108 m/s)
Has a frequency (f) and wavelength (λ)
c=fx λ
Higher frequency means higher energy photons
The higher the energy photon the more
penetrating is the radiation

7. Wireless Communications
• Multimedia wireless Communications at any Time
and Anywhere
• Brief history
• Ancient Systems: Smoke Signals, Carrier Pigeons
• Radio invented in the 1880s by Marconi
• Many sophisticated military radio systems were developed
during and after WW2
• Cellular has enjoyed exponential growth since 1988, with
more than 2 billion users worldwide today
• Ignited the recent wireless revolution, 1980-2003
• Growth rate tapering off
• Is there a future for wireless?

9. RADIO

10. An inventor named James Clerk
Maxwell was accredited for the initial
discovery of the uses of radio signals.
Although he did not invent the radio.
Nikola Tesla was the first to talk about
utilizing these signals for the use of
communication.

11. Another inventor named Guglielmo
Marconi built a radio system around
the same period capable of spanning
long distances . Many others
experimented and contributed to the
invention of radio including; Faraday,
Bose, and Popov.

16. radio waves are generated by an antenna and
they propagate in all directions as a straight line
radio waves travel at a velocity of 186.000 miles
per second
radio waves become weaker as they travel a long
distance

17. there are 3 modes of propagation:
 surface mode – for low frequency
waves
 direct mode – for high frequency
waves
 ionospheric mode – long distance
high frequency waves

18. ENCODING INFORMATION ON RADIO
WAVES
• What quantities characterize a radio
wave? – sort of info it carries,
frequency or type of encoding done..
• Two common ways to carry analog
information with
radio waves
– Amplitude Modulation (AM)
– Frequency Modulation (FM): “static
free”

21. Radar
• RADAR is a method of using electromagnetic waves to remote-
sense the position, velocity and identifying characteristics of
targets.
Two Basic Radar Types
• Pulse Transmission
• Continuous Wave

23. Types of radar
1 Primary radar 2 secondary radar
Pulse
radar
Continues
radar
Intra pulse
modulated
Pulse
modulated
modulate
d
Un
modulated
Imaging Radar
Non-Imaging Radar

24. How pulse Radar Works

25. Frequency modulation looks like
On the above diagram, the frequency of the wave is low on the left
and it slowly increases as you look right. The different frequencies of
the wave will lie in a range called bandwidth. Radars use bandwidth
for several reasons regarding the resolution of a data image, memory
of the radar and overuse of the transmitter. For instance, a high
bandwidth can yield a finer resolution but take up more memory.

26. Continuous- Wave Radar
CW radar sets transmit a high-frequency signal
continuously. The echo signal is received and
processed. The receiver need not to be mounted at
the same place as the transmitter. Every firm civil radio
transmitter can work as a radar transmitter at the
same time, if a remote receiver compares the
propagation times of the direct signal with the reflected
one. Tests are known that the correct location of an
airplane can be calculated from the evaluation of the
signals by three different television stations.

27. Frequency
Wavelength 1 mm1 km 1 m 1 µm 1 nm
1 MHz 1 GHz
IR UV
109
Hz
0 1 2 3 4 5 6 7 8 9 10 11 12
30 20 10 8 6 5 4 39 7
Allocated Frequency (GHz)
Wavelength (cm)
X-BandC-BandS-BandL-BandUHF
VHF
Visible
1012
Hz
Ku
K
Ka
W

28. Radar observables:
• Target range
• Target angles (azimuth & elevation)
• Target size (radar cross section)
• Target speed (Doppler)
• Target features (imaging)
Antenna
Transmitted
Pulse
Target
Cross
Section
Propagation
Reflected
Pulse
(“echo”)

29. Radar Range Measurement
Transmitted
Pulse
Reflected
Pulse
Range
Target
• Target
range =
cτ
2
wherec = speed of light
τ = round trip time

30. Use of radar
 Detection and search radar
 missile guidance systems
 Radar for biological research
 Air traffic control and navigation radar
 Weather-sensing radar systems
 Parking of vehicles
 military purpose
 electron pressure
 Temperature measurement

32. Radar Can Measure Pressure
The strength of the echo received from the
ionosphere measures the number of electrons
able to scatter radio waves or what we call
electron pressure

33. Radar Can Measure Temperature
Some electrons are
moving due to heat - In
this case the echo is
scattered
The echo will contain a
range of frequencies close
to the transmitter
frequency
As the temperature
increases, the electrons
move faster
So radar can act like a
thermometer and measure
the temperature of the
ionosphere

34. • Atmospheric attenuation
• Reflection off of earth’s
surface
• Over-the-horizon
diffraction
• Atmospheric refraction
Radar beams can be attenuated, reflected and
bent by the environment
Radar beams can be attenuated, reflected and
bent by the environment

35. Atmospheric Effects

36. The AN/TPS-43 radar
system, with a 200 mile
range, was the only Air
Force tactical ground based
long range search and
warning radar for nearly two
decades. Most of the
AN/TPS-43 radars are being
modified to the AN/TPS-75
configuration.
3-D Air Search Radar

37. History of wireless communication
• Guglielmo Marconi invented the wireless telegraph in 1896
 Communication by encoding alphanumeric characters in
analog signal
 Sent telegraphic signals across the Atlantic Ocean
• 1914 first voice communication over radio waves
• Communications satellites launched in 1960s
• Advances in wireless technology
• More recently
 Radio, television, mobile telephone, communication
satellites
 Satellite communications, wireless networking, cellular
technology

38. Early uses
 It was very much for entertainment
often playing popular music.
 It was also the fastest medium to
release news.
 Unlike previous publications such as
newspapers the radio was instant .
Radio was reserved for military uses
during the first part of the 20th
century.

40. Advantages and disadvantages of
wireless communication
advantages:
 mobility
 a wireless communication network is a solution in
areas where cables are impossible to install (e.g.
hazardous areas, long distances etc.)
 easier to maintain
disadvantages:
 has security vulnerabilities
high costs for setting the infrastructure
unlike wired comm., wireless comm. is influenced by
physical obstructions, climatic conditions, interference
from other wireless devices

41. Current Wireless Systems
• Cellular systems
• Wireless LANs
• Satellite Systems
• Paging Systems
• Bluetooth
• Ultrawideband Radios
• Zigbee Radios

42. Cellular Systems:
Reuse channels to maximize capacity
• Geographic region divided into cells
• Frequencies/timeslots/codes reused at spatially-
separated
locations.
• Co-channel interference between same color cells.
• Base stations/MTSOs coordinate handoff and
control functions
• Shrinking cell size increases capacity, as well as
networking burden
BASE
STATIO
N MTS
O

43. Type of Cells
Satellite
Macrocell
Microcell
Urban
In-Building
Picocell
Global
Suburban
Basic Terminal
PDA Terminal
Audio/Visual Terminal

44. Type of Cells
• Cell radii can be vary from 10’s of meters in
buildings to 100’s of meters in the cities, up to
several km’s in the countryside.
• Macrocells, provide overall area coverage
• Microcells, Microcell will focus on slow
moving subscribers moving between
buildings.
• Picocells, Would focus on the foyer of a
theater, or exhibition centre.

45. The Wireless Revolution
Cellular is the fastest growing sector of communication
industry (exponential growth since 1982, with over 2 billion
users worldwide today)
• Three generations of wireless
• First Generation (1G): Analog 25 or 30 KHz FM, voice only, mostly
vehicular communication
• Second Generation (2G): Narrowband TDMA and CDMA, voice
and low bit-rate data, portable units.
2.5G increased data transmission capabilities
• Third Generation (3G): Wideband TDMA and CDMA, voice and
high bit-rate data, portable units

46. 0G (Zero Generation Mobile System)
At the end of the 1940’s, the first radio telephone
service was introduced, and was designed to users in
cars to the public land-line based telephone
network.
In the 1960’s, a system launched by Bell Systems,
called, Improved Mobile Telephone Service (IMTS),
brought quite a few improvements such as direct
dialing and more bandwidth. The very first analog
systems were based upon IMTS and were created in
the late 60s and early 70s.

47. 1G Technology
1G refers to the first-generation of
wireless telephone technology was
developed in 1970’s.
1G had two major improvements:
the invention of the microprocessor
the digital transform of the control link between
the phone and the cell site.
Analog signal

48. 2G Technology
Around 1980’s
Better quality & capacity - More people could use there
phones at the same time
Digital Signals – consist of 0’s & 1’s

49. Previous Technology - 2G
Digital – consist of 0’s and 1’s
Digital signal:
 1.Low level, 2.High level, 3.Rising edge
and 4.Falling edge

50. Previous Technology - 2G
Digital data can be compressed and multiplexed
much more effectively than analog voice
encodings
Multiplexing -multiple analog message signals
or digital data streams are combined into one
signal
For 1 and 2G standards, bandwidth maximum is
9.6 Kbit/sec, (I.E) approximately 6 times slower
than an ISDN

51. Previous Technology - 2G
Allows for lower powered radio signals that
require less battery
Power–CODEC introduction -program that
encodes and decodes digital data stream or signal
Translates data from digital to analog and vice
versa

52. Previous Technology - 2G

53. Advantages in Previous Technology
- 2G
The digital voice encoding allows digital error
checking
increase sound quality
lowers the noise level
Going all-digital allowed for the introduction of
digital data transfer
SMS –“short message service”
E-mail

54. Disadvantages in Previous
Technology - 2G
Cell towers had a limited coverage area
Jagged Decay curve
 Abrupt dropped calls
 Analog –gradual sound reduction
“Spotty” coverage

55. 3G Technology
Large capacity and broadband capabilities
Allows the transmission of 384kbps for mobile
systems and up to 2Mbps
Increased spectrum efficiency –5Mhz
A greater number of users that can be simultaneously
supported by a radio frequency bandwidth
High data rates at lower incremental cost than 2G–
Global roaming

56. Previous Technology - 3G
CDMA –Code Division Multiple Access
Form of multiplexing
Does not divide up the channel by time or frequency
Encodes data with a special code associated with each
channel

57. Code Division Multiple Access

58. Types of Multiplexing
FDMA – Frequency Division Multiple Access
Each phone call is allocated one frequency for the entire
duration of the call

59. Types of Multiplexing
TDMA - Time Division Multiple Access
Each phone call is allocated a spot in the frequency for a
small amount of time, and "takes turns" being transmitted

60. Types of Multiplexing
CDMA - Code Division Multiple Access
Each phone call is uniquely encoded and transmitted across
the entire spectrum, in a manner known as spread spectrum
transmission

61. Reasons for New Research
Even though 3G has successfully been introduced
to mobile users, there are some issues that are
debated by 3G providers and users.
High input fees for the 3G service licenses
Great differences in the licensing terms
3G phones are expensive

62. Fourth Generation

63. What is 4G?
Fourth Generation Technology
Faster and more reliable
100 Mb/s
Lower cost than previous generations
Multi-standard wireless system
Bluetooth, Wired, Wireless
Ad Hoc Networking
IPv6 Core
OFDM used instead of CDMA
Potentially IEEE standard 802.11n
Most information is proprietary

64. Communications Architecture
Broadcast layer:
fix access points, (i.e.) cell tower connected by fiber,
microwave, or satellite (ISP)
Ad-hoc/hot-spot layer:
wireless LANs (i.e. internet at Starbuck’s)

65. Communications Architecture
Personal Layer Gateway:
devices that connect to upper layers; cell phone, fax,
voice, data modem, MP3 players, PDAs
Info-Sensor layer:
environmental sensors
Fiber-optic wire layer:
high speed subterranean labyrinth of fiber optic cables
and repeaters

66. Ad Hoc Networks
 Spontaneous self
organization of networks of
devices
 Not necessarily connected to
internet
 4G will create hybrid wireless
networks using Ad Hoc
networks
 Form of mesh networking–
Very reliable

67. Enhance Mobile Gaming
Experience enhance wireless capabilities that
deliver mobile gaming interaction with less
than five seconds
Play online multi player games while traveling
at high speeds or sitting outside

68. Broadband access in Remote
location
4G will provide a wireless alternative for broadband access
I will provide first opportunity for broadband access in
remote locations without an infrastructure to support
cable or DSL access.

69. Wireless Local Area
Networks (WLANs)
 WLANs connect “local” computers (100m range)
 Breaks data into packets
 Channel access is shared (random access)
 Backbone Internet provides best-effort service
 Poor performance in some apps (e.g. video)
01011011
Internet
Access
Point
0101 1011

70. Wireless LAN Standards
• 802.11b (Current Generation)
• Standard for 2.4GHz ISM band (80 MHz)
• Frequency hopped spread spectrum
• 1.6-10 Mbps, 500 ft range
• 802.11a (Emerging Generation)
• Standard for 5GHz NII band (300 MHz)
• OFDM with time division
• 20-70 Mbps, variable range
• Similar to HiperLAN in Europe
• 802.11g (New Standard)
• Standard in 2.4 GHz and 5 GHz bands
• OFDM
• Speeds up to 54 Mbps
In 200?,
all WLAN
cards will
have all 3
standards

71. Satellite Systems
• Cover very large areas
• Different orbit heights
• GEOs (39000 Km) versus LEOs (2000 Km)
• Optimized for one-way transmission
• Radio (XM, DAB) and movie (SatTV) broadcasting
• Most two-way systems struggling or bankrupt
• Expensive alternative to terrestrial system
• A few ambitious systems on the horizon

72. Paging Systems
• Broad coverage for short messaging
• Message broadcast from all base stations
• Simple terminals
• Optimized for 1-way transmission
• Answer-back hard
• Overtaken by cellular

73. Bluetooth
• Cable replacement RF technology (low cost)
• Short range (10m, extendable to 100m)
• 2.4 GHz band (crowded)
• 1 Data (700 Kbps) and 3 voice channels
• Widely supported by telecommunications, PC,
and consumer electronics companies
• Few applications beyond cable replacement

74. SIXTH SENSE
TECHNOLOGY

75. PHYSICAL WORLD
Objects ~ Gestures
Gestures ~ Interaction
INTERACTIVE
TECHNOLOGIES

76. SOME OF INTERACTIVE
TECHNOLOGIES
•Multi touch Systems
•Flexible screens
•Multi touch IWB (Interactive White Boards)
•Smart interactive Tables & multi touch
desks
•Microsoft Surface
•SIXTH SENSE TECHNOLOGY

77. INTRODUCTION
•SixthSense is a wearable gestural interface that
augments the physical world around us with digital
information.
•Technology that plays with Human gestures to
make the world more interactive and workflow
much easier.
•Pranav Mistry, of Indian origin, a PhD student in
the Fluid Interfaces Group at the MIT Media Lab is
the mastermind behind the sixth sense technology.

78. EARLIER
EXPLORATIONS
•Gesture interface device
•Sticky notes
•Pen that can draw in 3-D
•Google Maps in a physical world

79. SO WHY SIXTH
SENSE??
•Hereby Physical world is painted with the
digital information.
•You can carry your digital world with you
wherever you go.
•You can start with any wall or any surface
as an interface even your palm.

80. PROTOTYPE &
CONSTRUCTION

81. CAMERA
•Also called as digital
eye as it analyses the
digital pixels.
•It captures the object
in view and tracks the
gestures.

82. PROJECTOR
•The projector projects
visual information
enabling surfaces and
physical objects to be
used as interfaces.
•It displays data sent
from the smart phone
on any surface in
view–object, wall, or
person.

83. SMART PHONE
•A web enabled smart
phone in the user’s
pocket processes the
video data.
•Other software
searches the web and
interprets the hand
gestures.

84. COLOR MARKERS
•At the tip of the user’s
fingers.
•Helps the webcam to
recognize the
gestures.
•The movements and
arrangements of these
makers are interpreted
into gestures.

85. WORKING?
•Images
•Pictures
•Gesture
s
Info on
surface
captur
e
Send for
processing
Reflect on
desired
surface
Project image
Send
Info

86. APPLICATIONS

87. •Watch related
videos on the
newspaper
articles you are
reading.

88. . Check the time
just by drawing
a circle on the
wrist.

89. •To make a call,
virtual keypad is
shown on your
palm.

90. Get product information by using
image recognition technology..

91. Get book reviews,
ratings & other
relevant
information

92. •Get flight
updates
regarding
timing of the
flight.

93. •Projects relevant
information regarding
a person.
•
Click pictures just by
forming “framing
gesture”.

94. •Organize, sort & resize pictures by
projecting them on a surface.
•Call up the map and use
thumbs & index fingers to
navigate through.

95. •Zoom in & zoom out
using intuitive hand
movements.
•Drawing application by
tracking fingertip
movements.

96. CONCLUSION
•Integrating information to everyday objects
will not only help us to get rid of the digital
divide, but will also help us in some way to
stay human, to be more connected to our
physical world.
•IT WILL NOT END UP IN MAKING US
MACHINES SITTING IN FRONT OF
OTHER MACHINES!!

97. Sixth Sense Technology By
Pranav Mistry

98. Design Challenges
• Hardware Design
• Precise components
• Small, lightweight, low power
• Cheap
• High frequency operations
• System Design
• Converting and transferring information
• High data rates
• Robust to noise and interference
• Supports many users
• Network Design
• Connectivity and high speed
• Energy and delay constrains

99. The END
THANK YOU