principles of wireless communications - uni- · pdf fileprinciples of wireless communications...

Dr. Ing. Dirk Wübben

Department of Communications EngineeringInstitute for Telecommunication and High Frequency

University of Bremen, Germany

Phone: +49 421 [email protected]

www.ant.uni-bremen.de

Principles of Wireless Communications

3rd BaSoTi Summer School, Riga, Latvia

Dirk Wübben Principles of Wireless Communication 2UniversitätBremen

Course Overview

1. IntroductionHistorical overviewExamples for wireless communication systems

2. Signals and SystemsSummary of mathematical description for signals and systems

3. Principles of Digital Wireless CommunicationsBasic components of a digital wireless communication system

4. Orthogonal Frequency Division MultiplexingMobile Fading ChannelOFDM: an elegant way of equalization


Early History of Wireless Communication

Wireless Communication: Transmission of information without wiresMany people in history used light for communication

Optical telegraphs (Greece, 350 BC)Signaling towers (flags) (China, Han-Dynasty, 206 BC – 24 AC)Smoke signals for communication (Greece, 150 BC)Optical telegraph, Claude Chappe (1794)


Electromagnetic Waves

Discovery of electromagnetism1820 Oersted Electric current generates magnetic field

1831 Faraday demonstrates electromagnetic induction

Electromagnetic Waves1864 Maxwell Theory of electromagnetic fields, wave equations

1895 Hertz Proof of electromagnetic waves


History of Communication

Application to Communication1837 Morse First Telegraph1861 Reis First Telephone (Patent Bell 1876)

Wireless Communication1901 Marconi First transatlantic transmissionfirst demonstration of wireless telegraphy (digital!)long wave transmission, high transmission power necessary (> 200kw)

Digital Communication1948 Shannon „A Mathematical Theory of Communication“


1. Generation of Mobile CommunicationA-Netz (1958-1977)

Call set up from mobile to fixed onlyNo handover between cellsapprox. 11000 subscriber (1971)

B-Netz (1972-1994)Germany, Austria, LuxembourgCall set up from fixed to mobile with knowledge of mobile‘s position1979 13 000 Subscriber, heavy „Mobiles“ mainly in carsapprox. 27.000 subscribers (1986)less than 1 Mio. subscribers worldwide

C-Netz (1985)Handover between cellsAutomatical localizationDigital siginalingapprox. 850.000 subscriber (1993) Der Abschied von ABC- Eine Zeitreise zu den wichtigsten

Stationen, Broschüre der T-Mobil, www.handy-sammler.de


2. Generation of Mobile CommunicationDigital Transmission to improve system capacity, coverage and QoS

Typical Networks: IS-95 (US), D-AMPS (US), PDC (Japan) andGSM

Groupe Spéciale Mobile (1982)Development of European digital mobile communication system

Global System for Mobile Communication (1992)Germany: D-Netz (900 MHz) and E-Netz (1800 MHz)Voice is the dominating application but systems are capable of fax, data, SMS, MMS, …International RoamingData rate 9,6 kbit/s (compare ISDN: 64 kbit/s and DSL: ≥ 16 Mbit/s)More than 1 Billion subscriber worldwide (2004)

Extensions for higher data rate (2.5 G)High Speed Circuit Switched Data : 57,6 kbit/sGeneral Packet Radio System : 115,2 kbit/sEnhanced Data Rate for GSM Evolution : 384 kbit/s SonyEricsson P900, 2004

www.sonyericsson.de

Motorola International 1000www.handy-sammler.de/Museum/13.html


3. Generation of Mobile Communication3G

World-wide harmonization (services, data rates) Improved/extended data services, capacity and flexibilityStandardization at ITU: IMT-2000User Data Rates: 144 kbit/s – 2 Mbit/s

Universal Mobile Telecommunications System (UMTS)One implementation of IMT-2000 with compatibility to GSMNew Air Interface (W-CDMA)New frequency range (2 GHz)Core Network from GSM/GPRS (first release, R’99), Further evolvement in releases (R’99, R4, R5, R6)

ApplicationsVideo-Conferencing and Video-StreamingMobile officeMedical emergency Localization-based servicesDownload of music

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Short-range Wireless Communication

Wireless Local Area Networks (WLAN)Wireless network connection with limited coverageData rates up to 54 Mbit/sOrthogonal Frequency Division Multiplexing (OFDM)

BluetoothReplacement for short wired connectionsData rate ca. 1 Mbit/s

Ultra WideBand (UWB)Very high data ratesCoexistence with other standards


Frequencies for Communication

VLF = Very Low Frequency UHF = Ultra High FrequencyLF = Low Frequency SHF = Super High FrequencyMF = Medium Frequency EHF = Extra High FrequencyHF = High Frequency UV = Ultraviolet LightVHF = Very High Frequency

Frequency and wave length:

wave length λ, speed of light c0 ≅ 3x108m/s, frequency f

1 Mm300 Hz

10 km30 kHz

100 m3 MHz

1 m300 MHz

10 mm30 GHz

100 μm3 THz

1 μm300 THz

visible lightVLF LF MF HF VHF UHF SHF EHF infrared UV

optical transmissioncoax cabletwisted pair

λ =c0f


Frequencies and Regulations

ITU-R holds auctions for new frequencies, manages frequency bands worldwide (WRC, World Radio Conferences)

E urope U S A Japan

C e llu lar P hones

G SM 450-457 , 479-486 /460-467 ,489-496 , 890-915/935-960 , 1710-1785/1805-1880 U M TS (FD D ) 1920-1980, 2110-2190 U M TS (TD D ) 1900-1920, 2020-2025

AM P S , TD M A , C D M A 824-849 , 869-894 TD M A , C D M A , G SM 1850-1910, 1930-1990

P D C 810-826 , 940-956 , 1429-1465, 1477-1513

C ord less P hones

C T1+ 885-887 , 930-932 C T2 864-868 D E C T 1880-1900

P AC S 1850-1910, 1930-1990 P AC S -U B 1910-1930

P H S 1895-1918 JC T 254-380

W ireless L AN s

IE E E 802.11 2400-2483 H IP E R L AN 2 5150-5350, 5470-5725

902-928 IE E E 802.11 2400-2483 5150-5350, 5725-5825

IE E E 802.11 2471-2497 5150-5250

O thers R F-C ontro l 27, 128 , 418, 433 , 868

R F-C ontro l 315, 915

R F-C ontro l 426 , 868

principles of wireless communications - uni- · pdf fileprinciples of wireless communications...

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