Swapna Kumar & Marilyn Ochoa University of Florida, USA Abstract
Wireless communication dr. s. swapna kumar
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Transcript of Wireless communication dr. s. swapna kumar
Wireless Communication
Prof. Dr. S. Swapna Kumar
Dept. of Electronics and Communication Engg.
Vidya Academy of Science and Technology, Thalakkottukara, Thrissur,
Kerala- 680501, India
Michael Faraday and James Clerk Maxwell,inventors of the field concept in electricity and magnetism.
Maxwell’s Equations
Wave Propagation
electric
field
magnetic
field
Notice that the electric and magnetic fields are at right angles to one another!
Emitted by sinusoidal current running through a wire (transmitting antenna)
What is Frequency?
• Wave vocabulary– Amplitude
– Frequency
– Period
– Wavelength
– Bandwidth
cf
Name 900 Mhz 2.4 Ghz 5 Ghz
Range 902 - 928 2.4 - 2.4835 5.15 - 5.35
Bandwidth 26 Mhz 83.5 Mhz 200 Mhz
Wavelength .33m / 13.1” .125m / 4.9” .06 m / 2.4”
Radio Frequency (RF) Spectrum
Transmission Media
7.6
GUIDED MEDIA
WIRELESS• Any type of electrical or electronic operation accomplished without use of
wires.
• Wireless connections use air to connect sending and receiving devices
COMMUNICATION
Sending
device message
Connection
device
Communication
channels
Connection
device message
Receiving
device
• It is transmission of signals i.e. sending of electromagnetic waves by electronic transmitters
• Channel is a division in transmission medium
WHAT IS WIRELESS COMMUNICATION?
• Transmitting/receiving voice and data using electromagnetic waves in open space.
• The information from sender to receiver is carried over a well defined frequency band(channel).
• Each channel has a fixed frequency bandwidth & capacity(bit rate).
• Different channels can be used to transmit information in parallel and independently.
EARLY WIRELESS WORK
Early inventors –Alexander Graham Bell, GaglielmoMarconi and John Logie Baird
• In 1878, David E Hughes induced electromagnetic waves
• In 1888, Thomas Alva Edison used a vibrator magnet for induction transmission, gave system of signals.
History: Timeline
1894 –experiments began with
Hertzian Waves
1896 – Wireless Telegraph &
Signal Company established
1901 – first trans-Atlantic
signal received
1905 – first distress signal
successful using Morse Code
1919 – RCA incorporated
1939-1945 – WWII US Military initiates
radio data transmission technology
1971 –ALOHANET
experiment, first wireless
LAN
1973 –Motorola
creates first mobile cellular
telephone
1983 – America enters cellular
telephone market
1987 – FCC encourages use
of 800Mhz spectrum
1990 – IEEE creates work
group to establish
wireless LAN standards
1997 – 802.11 established as wireless LAN
standard
Why Deploy Wireless?
• Unlicensed bands.
• Global coverage
• No bunch of wires running.
• Cost savings over wire line.
• Can not run wire to locations needed.
• Stay connected, flexibility to connect multiple devices.
“Do I really need all of that wire?”
Nightmare jumble of cables
“Wireless Communication Waves”
Wireless Communication networks are generally implemented with some type of remote information
transmission system that uses electromagnetic waves.
Propagation methods
How communication takes place
Transmitting signalReceived signal
satellite
Transmitting antenna
Receivingantenna
CURRENT WIRELESS SYSTEMS
• CELLULAR SYSTEM
• WIRELESS LANs
• SATELLITE SYSTEM
• PAGING SYSTEM
• PANs(BLUETOOTH)
TYPICAL FREQUENCIES
• FM RADIO 88 MHZ
• TV BROADCAST 200 MHZ
• GSM PHONES 900 MHZ
• GPS 1.2 GHZ
• PCS PHONES 1.8 GHZ
• BLUETOOTH 2.4 GHZ
• Wi-Fi 2.4 GHZ
WIRELESS NETWORKS
Wireless network is a network set up by using radio signal frequency to
communicate among computers and other network devices. Sometimes
it’s also referred to as WiFi network or WLAN.
• Wireless devices– Distance: 300 feet (90 meters)– Bandwidth: 54 Mbps– Can also include Voice over IP (VoIP)
Types:- Digital networks –consists routers that route data
Analog networks – consists switches establishing connections
The Wireless Landscape
The Wireless Landscape
21
Advantages of Wireless Networking
• Mobility
• Easier and less expensive installation
• Increased reliability
• Disaster recovery
22
Disadvantages of Wireless Devices
• Wireless communication disadvantages
– Radio signal interference
– Security issues
– Health risks
FUTURE
Major role in development of technology
High speed data transfer
Data transfer over large area or distance
Eco friendly and non-hazardous ways have to be found out
Has to be made more secured
To Be Continued….(Convergence)
The Institute of Electrical and
Electronics Engineers = IEEE
IEEE
Journals
Conference
Proceedings
Standards
IBM Journal
eBooks
E-learning
Library
Thank You!!