Wireless Communication

Prof. Dr. S. Swapna Kumar

Dept. of Electronics and Communication Engg.

Vidya Academy of Science and Technology, Thalakkottukara, Thrissur,

Kerala- 680501, India

drsswapnakumar@gmail.com

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!!