1

Wireless CommunicationSession 1

Introduction

M. Daneshvar Farzanegan

Soourosh.blogfa.comsmdanesh@yahoo.com

2

About this course The course is about the system aspects of Wireless communication.

Therfore, it covers:- Radio propagation models- Fading and other effects channel in wireless channel.- modulation and equalization techniques- Cellular concept- Frequency reuse and channel allocation algorithms- Networking issues (MAC, network and transport layer, principale)

It does not cover:- Antenna Design- Propagation waves differential equations (Maxwell Equation)- speech coding or other signal processing aspects

- software-centric aspects (e.g., operating systems, mobile agents, smart phone programming)

It is focused on mechanisms, and avoids as much as possible a detailed (and boring) description of standards

However, it does propose an insight on IEEE 802.11 and cellular networks

Acronyms are abundant and we have to cope with them…

The course is also an attempt to get closer to the “real world”

Text books

http://www.inf.fu-berlin.de/inst/ag-tech/resources/mobkom/mobile_communications.htm

- J. Schiller: Mobile Communications, Second EditionAddison-Wesley, 2004

- W. Stallings: Wireless Communications & Networks, Second Edition, Prentice Hall, 2005

http://www.WilliamStallings.com/Wireless/Wireless2e.html

- Andrea Goldsmith : Wireless CommunicationsStanford University Press, 2004

- M. Schwartz: Mobile Wireless CommunicationsCambridge University Press, 2005

Wireless communication and mobility

Aspects of mobility:user mobility: users communicate “anytime, anywhere, with anyone”device portability: devices can be connected anytime, anywhere to the

network

Wireless vs. mobile Examples stationary computer (desktop) Cable-Internet laptop in a hotel wireless LANs in historic buildings smart phone

The demand for mobile communication creates the need for integration of wireless networks or mobility mechanisms into existing fixed networks:telephone network cellular telephony (e.g., GSM, UMTS, LTE)

local area networks Wireless LANs (e.g., IEEE 802.11 or “WiFi”)

Internet Mobile IP

5

Examples of applications (1/2)

Person to person communication (e.g., voice, SMS)

Person to server (e.g., location-based services, timetable consultation, telebanking)

Vehiclesposition via GPS

local ad-hoc network with vehicles close-by to prevent accidents, guidance system, adaptive cruise control

transmission of news, road condition, weather, music via Digital Audio Broadcasting

vehicle data (e.g., from buses, trains, aircrafts) transmitted for maintenance

Disaster situationsreplacement of a fixed infrastructure in case of earthquakes,

hurricanes, fire etc.

Military networks

6

Upcoming application: road traffic

GSM, UMTSTETRA, ...

http://ivc.epfl.chhttp://www.sevecom.org

7

Examples of applications (2/2)

Traveling salespeopledirect access to customer files stored in a central location

consistent databases for all agents

mobile office

Replacement of fixed networksSensors

trade shows networks

LANs in historic buildings

Entertainment, education, ...outdoor Internet access

travel guide with up-to-datelocation dependent information

ad-hoc networks formulti user games

Location-dependent advertising

8

Location dependent services

Location aware serviceswhat services, e.g., printer, fax, phone, server etc. exist in the

local environment

Follow-on servicestransmission of the actual workspace to the current location

Information services„push“: e.g., current special offers in the shop nearby

„pull“: e.g., where is the closest Migros?

Support servicescaches, intermediate results, state information etc. „follow“ the

mobile device through the fixed network

Location-Based Services (LBSs)Foursquare, Facebook Mobile,…

9

Quad band GSM (850, 900, 1800, 1900 MHz)

GPRS/EDGE

Tri band UMTS/HSDPA (850, 1900, 2100 MHz)

LTE

GPS + accelerometers

WiFi (802.11b/g/a/n)

Bluetooth 2.1

Modern mobile phones

10

Wireless enabled devices

11

Satellite Communications

BTCC-45 Bluetooth GPS Receiver

European attempt: Galileo

Global Positioning System (GPS)30 satellites currently

Orbit altitude: approx. 20,200 kmFrequency: 1575.42 MHz (L1)

Bit-rate: 50 bpsCDMA

Iridium 9505A Satellite Phone

Iridium Satellite

Supports 1100 concurrent phone callsOrbit altitude: approx. 780 km

Frequency band: 1616-1626.5 MHzRate: 25 kBdFDMA/TDMA

12

WiMAX GP3500-12 omnidirectional antenna

Frequency band: 3400-3600 MHzGain: 12 dBi

Impendence: 50 Power rating: 10 Watt

Vertical beamwidth: 10

WiMAX PA3500-18 directional antennaFrequency band: 3200-3800 MHz

Gain: 12 dBiImpendence: 50

Power rating: 10 WattVertical beamwidth: 17

Horizontal beamwidth: 20

Wireless “Last Mile”: WiMax

13

IEEE 802.15.4 Chipcon Wireless TransceiverFrequency band: 2.4 to 2.4835 GHz

Data rate: 250 kbpsRF power: -24 dBm to 0 dBm

Receive Sensitivity: -90 dBm (min), -94 dBm (typ)Range (onboard antenna): 50m indoors / 125m ourdoors

TelosB Sensor Mote

MicaZ

Imote2

Wireless sensors

Iris Mote

Cricket Mote

14

RFID tag

SDI 010 RFID Reader

ISO14443-A and B (13.56 MHz)Operating distance: 1cm

Communication speed: up to 848 Kbit/s

Radio-frequency Identification (RFID)

15

Implantable Cardioverter Defibrillator (ICD)

Medical Implants

Operating frequency: 175kHzRange: few centimeters

Medical Implant Communication Service (MICS)Frequency band: 402-405 MHz

Maximum transmit power (EIRP): 25 microwattRange: few meters

16

Vehicular communications

16

Dedicated short-range communications (DSRC)Frequency band (US): 5.850 to 5.925 GHz

Data rate: 6 to 27 MbpsRange: up to 1000m

17

Tuning Frequency:30KHz - 30MHz (continuous)

Tuning Steps:1/5/10/50/100/500Hz & 1/5/9/10KHz

Antenna Jacket / Impedance:BNC-socket / 50Ohms

Max. Allowed Antenna Level :+10dBm typ. / saturation at -15dBm typ.

Noise Floor (0.15-30MHz BW 2.3KHz):Standard: < -131dBm (0.06μV) typ.

HighIP: < -119dBm (0.25μV) typ.Frequency Stability (15min. warm-up

period):+/- 1ppm typ.

Software Defined Radio

Application: Cognitive Radios Dynamic Spectrum Access

18

Mobile devices

performance

Pager• receive only• tiny displays• simple text

messages

Mobile phones• voice, data• web access• location based services

PDA• simple graphical displays• character recognition• simplified WWW

Laptop• functionally eq. to desktop• standard applications

Wireless sensors• Limited proc. power• Small battery

RFID tag• A few thousands

of logical gates• Responds only

to the RFID readerrequests (no battery)

19

Wireless networks in comparison to fixed networks

Higher data loss-rates due notably to interferencesemissions of e.g., engines, lightning, other wireless networks, micro-

wave ovens

Restrictive regulations of frequenciesUsage of frequencies has to be coordinated, useful frequencies are

almost all occupied (or at least reserved)

Lower transmission ratesFrom a few kbit/s (e.g., GSM) to a 100s of Mbit/s (e.g. WLAN)

Higher jitter

Lower security (higher vulnerability)

Radio link permanently shared need of sophisticated MAC

Fluctuating quality of the radio links

Unknown and variable access points authentication procedures

Unknown location of the mobile station mobility management

20

History of wireless communication (1/3)

Many people in History used light for communicationheliographs, flags („semaphore“), ...

150 BC smoke signals for communication(Greece)

1794, optical telegraph, Claude Chappe

Electromagnetic waves are of special importance:

1831 Faraday demonstrates electromagnetic induction

J. Maxwell (1831-79): theory of electromagnetic Fields, wave equations (1864)

H. Hertz (1857-94): demonstrateswith an experiment the wave character of electrical transmission through space(1886)

21

History of wireless communication (2/3)

1895 Guglielmo Marconi

first demonstration of wireless telegraphy

long wave transmission, high transmission power necessary (> 200kw)

1907 Commercial transatlantic connections

huge base stations (30 to 100m high antennas)

1915 Wireless voice transmission New York - San Francisco

1920 Discovery of short waves by Marconi

reflection at the ionosphere

smaller sender and receiver, possible due to the invention of the vacuum tube (1906, Lee DeForest and Robert von Lieben)

22

History of wireless communication (3/3)

1928 Many TV broadcast trials (across Atlantic, color TV, TV news)

1933 Frequency modulation (E. H. Armstrong)

1946 First public mobile telephone service in 25 US cities (1 antenna per city…)

1976 Bell Mobile Phone service for NY city

1979 NMT at 450MHz (Scandinavian countries)

1982 Start of GSM-specificationgoal: pan-European digital mobile phone system with roaming

1983 Start of the American AMPS (Advanced Mobile Phone System, analog)

1984 CT-1 standard (Europe) for cordless telephones

1992 First deployment of GSM

2002 First deployment of UMTS

2010 - 2013 LTE standards mature, first trials

Wireless systems: development over the last 25 years

cellular phones satellites wireless LANcordlessphones

1992:GSM

1994:DCS 1800

2001:UMTS/IMT-2000

CDMA-2000 (USA)

1987:CT1+

1982:Inmarsat-A

1992:Inmarsat-BInmarsat-M

1998:Iridium

1989:CT 2

1991:DECT 199x:

proprietary

1997:IEEE 802.11

1999:802.11b, Bluetooth

1988:Inmarsat-C

analog

digital

1991:D-AMPS

1991:CDMA

1981:NMT 450

1986:NMT 900

1980:CT0

1984:CT1

1983:AMPS

1993:PDC

2000:GPRS

2000:IEEE 802.11a,g

NMT: Nordic Mobile Telephone DECT: Digital Enhanced Cordless Telecom.AMPS: Advanced Mobile Phone System (USA) DCS: Digital Cellular SystemCT: Cordless Telephone PDC: Pacific Digital CellularUMTS: Universal Mobile Telecom. System PAN: Personal Area NetworkLTE: Long Term Evolution UMA: Universal Mobile Access

2005:VoIP-DECT

2010LTE

2009:IEEE 802.11n

2010UMA

24

Areas of research in mobile communication

Wireless Communicationtransmission quality (bandwidth, error rate, delay)

modulation, coding, interference

media access

...

Mobilitylocation dependent services, also called location based services

location transparency

quality of service support (delay, jitter)

security

...

Portabilityintegration (“system on a chip”)

power consumption

limited computing power, sizes of display, ...

usability

...

Security/privacy

25

Typical reference model

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Network Network

Radiolink

26

Influence of mobile communication on the layer model

location-dependent services

new applications, multimedia

adaptive applications

congestion and flow control

quality of service

addressing, routing, mobility management

hand-over

media access

multiplexing

modulation

power management, interference

attenuation

frequency allocation

Application layer

Transport layer

Network layer

Data link layer

Physical layer

security

27

Overlay Networks - the global view

wide area

metropolitan area

campus-based

in-house

verticalhand-over

horizontalhand-over

Integration of heterogeneous fixed andmobile networks with varyingtransmission characteristics

28

References (in addition to the recommended textbooks)

B. Walke: Mobile Radio Networks, Wiley, Second Edition, 2002

T. Rappaport: Wireless Communications, PrenticeHall, Second Edition, 2001

D. Tse and P. Viswanath: Fundamentals of Wireless Communication, Cambridge University Press, 2005