01 introduction to wireless communications

نظام المحاضرات االلكتروني

Mobile Communications Prepared for

Dijlah University College Department of Computer Techniques Engineering

2015 – 2016

Lecture 1 – Introduction to

wireless communications

Dr. Eng. Hussein Jamaluddin Khaleel

Email: [email protected]

http://www.duc.edu.iq/

mailto:[email protected]




Introduction – Wireless communications

• Wireless communications: the ability to transmit information using electromagnetic waves in open space

• Advantages: • Freedom from wires

• No cost of installing wires, no bunches of wires

• Moving around e.g. Bluetooth , Wi-Fi

• Global coverage • Where wired communication is not feasible or costly e.g. rural areas, battle field and

outer space

• Stay Connected • Any where any time

• Flexibility • Connect to multiple devices simultaneously

Dijlah University College 2


Introduction – Mobile communications

• Mobile communications: the ability to communicate on the move

• Mobility involves three aspects: • User mobility: users communicate wirelessly anywhere and anytime

• Device portability: provide connectivity to the network anywhere & anytime

• Coverage: availability of the network connection anywhere and anytime



Introduction – Cont.

• Wireless communication methods have been developing for more than one century

• Growth driven by advancements in: • Electronic circuits integration and miniaturization

• Signal processing techniques

• Wireless communication technologies

• Materials fabrication

• Resulted in large-scale deployment of portable radio equipment and communication networks that are: • Smaller, lighter and cheaper

• More reliable and powerful

• Easy to use



History of wireless communications

• Early inventions

• 150 BC - Smoke signals for communication, Greece

• Acoustic signals

• Flags (semaphore)

• 1792 - Optical telegraph, Claude Chappe, France



History of wireless communications

• Discovery of electromagnetic waves • 1864 - Maxwell theory of electromagnetic fields, England

• 1888 - Hertz demonstrates wave transmission through space, Germany

• Wireless transmissions • 1896 - Guglielmo Marconi demonstrates wireless telegraphy

• 1907 - Commercial transatlantic connections

• 1915 - Wireless voice transmission, New York - San Francisco

• 1920 - Discovery of short waves by Marconi

• 1926 - Train phone on the line Hamburg - Berlin


Maxwell

Hertz

Marconi


History of wireless communications – Cont.

• 1934 – Mobile communications for public safety, using AM

• 1935 – Edwin Armstrong demonstrated FM

• WWII – Accelerated the evolution of technology • Technology used in mobile communications and TV

• Number of mobile users increased significantly

• 1946


• 1946 – 1st Mobile Telephone Service (MTS) in the U.S.

• Single high-power transmitter, FM, manual dial

• Problem: uses high bandwidth because of technology limitations

• 1965 – Improved MTS (IMTS) was introduced

• Increased spectrum efficiency, automatic channel trunking

• Problem: poor service due to large number of subscribers


History of cellular communications

• 1968 – Concept of cellular mobile system proposed • Breaking coverage zone into small cells

• Advantage: re-use of portions of the spectrum in different cells

• Disadvantage: greater infrastructure and management

• 1st Generation mobile system (1G): analog • 1979 –1st cellular system in the world, by NTT, Japan

• 1981 – NMT-450 in Scandinavian countries

• 1983 – AMPS in the U.S.

• 1985 – ETACS in some European countries, C-450 in Germany

Not compatible with each other



History of cellular communications – Cont.

• 2nd generation mobile system (2G): digital, SMS • 1990 – GSM (Global System for Mobile), Europe

• 1991 – D-AMPS (Digital AMPS) or USDC (US Digital Cellular), U.S & Canada

• 1993 – PDC (Pacific Digital Cellular), Japan

• 1995 – CDMAOne, IS-95, IS-136, U.S.

• 2000 – GPRS (General Packet Radio Service), HSCSD (2.5G), MMS, Internet

• 2003 – EDGDE (Enhanced Data rates for GSM Evolution), improved data rate

• 3rd generation mobile system (3G): video calls, high speed Internet • 2000 – CDMA2000, U.S. and China

• 2000 – UMTS (Universal Mobile Telecommunication System) (W-CDMA), Europe, worldwide

• 2008 – HSPA (High Speed Packet Access), (HSDPA & HSUPA), higher data rates

• 2010 – HSPA+ (Evolved HSPA), further improved data rates



History of cellular communications – Cont.

• 4th generation mobile system (4G): ultra broadband, high-quality audio/video streaming • 2007 – Mobile WiMax, IEEE 802.16, U.S.

• 2009 – LTE (Long Term Evolution), Europe, worldwide

• 2013 – LTE Advanced, improvement on LTE, higher data rates

• 5th generation mobile system (5G): in progress • Concept in research and development phase

• Expected to achieve even higher data transmission rates

• Aims to achieve more efficient utilization of spectrum



Cellular evolution and standards

(Source: Wikipedia)



Early mobile phones, IMTS, 1960s-1970s

Evolution of mobile phones

More modern phones over the last 2 decades became smaller and lighter



Statistics: Percentage of telephone subscribers



Statistics: Mobile phone subscribers in Iraq


Source: ITU World Telecommunications


Classification of mobile radio systems

• Historically, “mobile” was used for radio devices that can move during operation • Home equipment: garage door opener, remote control

• Walkie-talkie

• Pagers

• Recently, “mobile” is used for a radio terminal that is attached to high speed mobile platform • Cellular phone in a fast moving car

• “Portable“ describes a radio terminal that can be hand-held and moved at walking-speed • Walkie-talkie and cordless phone



Examples of mobile radio systems

• Paging systems • Send brief messages (pages) to a subscriber (numeric, alphanumeric or voice)

• Notification, news

• Consist of network of telephone lines, base stations transmitters, radio towers for broadcasting of messages

• One-way communication (simplex)

• High-power transmitters

• Coverage may vary, within a city or a building

• Standards: • POCSAG in the 1970s

• ERMES and FLEX in the 1990s



Examples of mobile radio systems – Cont.

• Cordless telephone systems • Provide wireless extension to the telephone network within a limited area

• Two-way (duplex) communications

• Consists of a portable handset, connected to dedicated base station, which is connected to the telephone network

• 1st generation: household environment

• 2nd generation: allow mobility in workplace and public use with limited coverage in urban areas

• DECT (Digital European Cordless Telephone), Europe, 1993

• PACS, U.S., 1994



Examples of mobile radio systems – Cont.

• Cellular telephone system • Provide wireless connection over a large geographical area

• Coverage are is divided into small cells

• Radio channels are re-used by other distant cells

• Two-way (duplex) communications

• High quality voice and data services

• Uninterrupted call when users move from one cell to another

• Consist of (at high level): • Mobile stations (phone)

• Base stations (tower)

• Mobile switching center



Comparison of mobile radio systems

• Mobile station



Comparison of mobile radio systems – Cont.

• Base station



Trends in radio communications: Technologies

(Source: Y. D. Zhang, Villanova University)



Trends in radio communications: Speed and mobility

(Source: Y. D. Zhang, Villanova University)



Applications – I

• Mobility • transmission of news, road condition, weather, music

• personal communication using GSM

• position via GPS

• local ad-hoc network with vehicles close-by to prevent accidents, guidance system, redundancy

• vehicle data (e.g., from busses, high-speed trains) can be transmitted in advance for maintenance

• Emergencies • early transmission of patient data to the hospital, current status, first

diagnosis

• replacement of a fixed infrastructure in case of disasters, e.g. earthquakes, hurricanes, fire, etc.

• crisis, war, etc.

(Source: Prof. J. Schiller, FU Berlin)



Applications – II

• Travelling salesmen • direct access to customer files stored in a central location

• consistent databases for all agents

• mobile office

• Replacement of fixed networks • remote sensors, e.g., weather, earth activities

• flexibility for trade shows

• LANs in historic buildings

• Entertainment & education • outdoor Internet access

• intelligent travel guide with up-to-date location dependent information

• ad-hoc networks for multi user games




Goal – always best connected


GSM

GSM

LAN,

WLAN GSM

GSM, WLAN

GSM, Bluetooth

GSM, DSL/WLAN

DSL, WLAN



End of Lecture 1

Any questions?


01 introduction to wireless communications

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