CS647 - Advanced Topics In Wireless Networks

CS647 - Advanced Topics inWireless NetworksIntroductionDrs. Baruch Awerbuch & Amitabh MishraComputer Science DepartmentJohns Hopkins UniversityCS 6471.1

OutlineA case for mobility – many aspects History of mobile communication Market Wireless Networks Cellular Networks Ad hoc Networks Sensor Networks Areas of researchCS 6471.2

Computers for the next decades? Computers are integrated Technology is in the background small, cheap, portable, replaceable - no more separate devicescomputer are aware of their environment and adapt (“location awareness”)computer recognize the location of the user and react appropriately (e.g.,call forwarding, fax forwarding, “context awareness”))Advances in technology CS 647more computing power in smaller devicesflat, lightweight displays with low power consumptionnew user interfaces due to small dimensionsmore bandwidth per cubic metermultiple wireless interfaces: wireless LANs, wireless WANs, regionalwireless telecommunication networks etc. (“overlay networks“)1.3

Mobile communication Two aspects of mobility: Wireless vs. mobile88998989Examplesstationary computernotebook in a hotelwireless LANs in historic buildingsPersonal Digital Assistant (PDA)The demand for mobile communication creates the need forintegration of wireless networks into existing fixed networks: CS 647user mobility: users communicate (wireless) “anytime, anywhere, withanyone”device portability: devices can be connected anytime, anywhere to thenetworklocal area networks: standardization of IEEE 802.11,ETSI (HIPERLAN)Internet: Mobile IP extension of the internet protocol IPwide area networks: e.g., internetworking of GSM and ISDN1.4

Cell (Mobile) PhoneAs soon as the airplane’sdoor is opened, you canswitch on the cell phoneand you are connected .HellCS 647BeaconoMessageSignalsCell Phone contacts thenearest Base Station andregisters itself to getserviceCellular ServiceBase Station1.5

Applications - CellularMicrowave TowerWashington,DCCellChicagoMaintaining the telephone number across geographical areasin a wireless and mobile systemCS 6471.6

First Generation Cellular Systems and Services1970sDevelopments of radio and computer technologies for800/900 MHz mobile communications1976WARC (World Administrative Radio Conference) allocatesspectrum for cellular radio1979NTT (Nippon Telephone & Telegraph) introduces the firstcellular system in Japan1981NMT (Nordic Mobile Telephone) 900 system introducedby Ericsson Radio System AB and deployed in Scandinavia1984AMPS (Advanced Mobile Phone Service) introduced byAT&T in North AmericaCS 6471.7

Second Generation Cellular Systems and Services1982CEPT (Conference Europeenne des Post et Telecommunications)established GSM to define future Pan-European cellular RadioStandards1990Interim Standard IS-54 (USDC) adopted by TIA (TelecommunicationsIndustry Association)1990Interim Standard IS-19B (NAMPS) adopted by TIA1991Japanese PDC (Personal Digital Cellular) system standardized by theMPT (Ministry of Posts and Telecommunications)1992Phase I GSM system is operational1993Interim Standard IS-95 (CDMA) adopted by TIA1994Interim Standard IS-136 adopted by TIA1995PCS Licenses issued in North America1996Phase II GSM operational1997North American PCS deploys GSM, IS-54, IS-951999IS-54: North AmericaIS-95: North America, Hong Kong, Israel, Japan, China, etcGSM: 110 countriesCS 6471.8

Worldwide wireless subscribers (old prediction 20010001996CS 647199719981999200020011.9

Mobile phones per 100 people t talyDenmarkNorwaySwedenFinland010202005: 70-90% penetration in Western EuropeCS 647304050601.10

Worldwide cellular subscriber growth1200Subscribers [million]100080060040020001992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002Note that the curve starts to flatten in 2000 – 2004: 1.5 billion usersCS 6471.11

Third Generation Cellular Systems and Services (1/2) IMT-2000 (International Mobile Telecommunications2000):- Fulfill one's dream of anywhere, anytime communications a reality.Key Features of IMT-2000 include:- High degree of commonality of design worldwide;- Compatibility of services within IMT-2000 and with thenetworks;fixed- High quality;- Small terminal for worldwide use;- Worldwide roaming capability;- Capability for multimedia applications, and a widerange of services and terminals.CS 6471.12

Third Generation Cellular Systems and Services (2/2) Important Component of IMT-2000 is its abilityto provide high bearer rate capabilities:- 2 Mbps for fixed environment;- 384 Kbps for indoor/outdoor and pedestrianenvironment;- 144 kbps for vehicular environment. Standardization Work:- In progress Scheduled Service:- Started in October 2001 in Japan (W-CDMA)CS 6471.13

Foundation: ITU-R - Recommendations for IMT-2000 M.687-2 IMT-2000 concepts and goals M.816-1 framework for services M.817 IMT-2000 network architectures M.818-1 satellites in IMT-2000 M.819-2 IMT-2000 for developing countries M.1034-1 requirements for the radiointerface(s) M.1035 framework for radio interface(s) andradio sub-system functions M.1036 CS 647spectrum considerations M.1078 security in IMT-2000 M.1079 speech/voiceband data performance M.1167 framework for satellites M.1168 framework for management M.1223 evaluation of security mechanisms M.1224 vocabulary for IMT-2000 M.1225 .evaluation of transmission technologies. http://www.itu.int/imt1.14

Coverage Aspect of Next Generation Mobile banGlobalPicocellCS 647Microcell Macrocell Global1.15

MobilityVehicularPedestrianStationary0.01Global System for Mobile CommunicationsTransmission tions SystemMobile Broadband SystemLocal Multipoint Distribution SystemSatellite Universal MobileTelecommunicationsSystemBroadband Satellite Multimedia110100Data rate (Mb/s)Transmission capacity as a function of mobility in some radio access systemsCS 6470.11.16

Medical and Healthcare ApplicationsRemoteDatabasesATM SwitchIn orkATM SwitchWireless Remoteconsultation fromAmbulanceSensors on bodyPossibility for Remote consulting (including Audio Visual communication)CS 6471.17

Applications I Vehicles transmission of news, road condition, weather, music via DABpersonal communication using GSMposition via GPSlocal ad-hoc network with vehicles close-by to prevent accidents, guidancesystem, redundancyvehicle data (e.g., from busses, high-speed trains) can be transmitted inadvance for maintenanceEmergencies CS 647early transmission of patient data to the hospital, current status, firstdiagnosisreplacement of a fixed infrastructure in case of earthquakes, hurricanes,fire etc.crisis, war, .1.18

Typical application: road trafficUMTS, WLAN,DAB, DVB, GSM,cdma2000, TETRA, .adhocPersonal Travel Assistant,PDA, Laptop,GSM, UMTS, WLAN,Bluetooth, .CS 6471.19

Mobile and wireless services – Always Best ConnectedDSL/ WLAN3 Mbit/sGSM/GPRS 53 kbit/sBluetooth 500 kbit/sUMTS, GSM115 kbit/sLAN100 Mbit/s,WLAN54 Mbit/sUMTS2 Mbit/sGSM/EDGE 384 kbit/s,DSL/WLAN 3 Mbit/sGSM 115 kbit/s,WLAN 11 Mbit/sCS 647UMTS, GSM384 kbit/s1.20

Applications II Travelling salesmen Replacement of fixed networks direct access to customer files stored in a central locationconsistent databases for all agentsmobile officeremote sensors, e.g., weather, earth activitiesflexibility for trade showsLANs in historic buildingsEntertainment, education, . CS 647outdoor Internet accessintelligent travel guide with up-to-datelocation dependent informationad-hoc networks formulti user gamesHistoryInfo1.21

Location dependent services Location aware services Follow-on services „push“: e.g., current special offers in the supermarket„pull“: e.g., where is the Black Forrest Cherry Cake?Support services automatic call-forwarding, transmission of the actual workspace to thecurrent locationInformation services what services, e.g., printer, fax, phone, server etc. exist in the localenvironmentcaches, intermediate results, state information etc. „follow“ the mobiledevice through the fixed networkPrivacy CS 647who should gain knowledge about the location1.22

Mobile devicesPager receive only tiny displays simple textmessagesPDA graphical displays character recognition simplified WWWLaptop/Notebook fully functional standard applicationsSensors,embeddedcontrollersMobile phones voice, data simple graphical displaysPalmtop tiny keyboard simple versionsof standard applicationswww.scatterweb.netperformanceCS 6471.23

Effects of device portability Power consumption limited computing power, low quality displays, small disks due tolimited battery capacityCPU: power consumption CV2fC: internal capacity, reduced by integrationz V: supply voltage, can be reduced to a certain limitz f: clock frequency, can be reduced temporallyz Loss of data Limited user interfaces compromise between size of fingers and portabilityintegration of character/voice recognition, abstract symbolsLimited memory CS 647higher probability, has to be included in advance into the design(e.g., defects, theft)limited value of mass memories with moving partsflash-memory or ? as alternative1.24

Wireless networks in comparison to fixed networks Higher loss-rates due to interference Restrictive regulations of frequencies connection setup time with GSM in the second range, several hundredmilliseconds for other wireless systemsLower security, simpler active attacking local some Mbit/s, regional currently, e.g., 53kbit/s with GSM/GPRSHigher delays, higher jitter frequencies have to be coordinated, useful frequencies are almost alloccupiedLow transmission rates emissions of, e.g., engines, lightningradio interface accessible for everyone, base station can be simulated,thus attracting calls from mobile phonesAlways shared medium CS 647secure access mechanisms important1.25

Early history of wireless communication Many people in history used light for communicationheliographs, flags („semaphore“), . 150 BC smoke signals for communication;(Polybius, Greece) 1794, optical telegraph, Claude Chappe Here electromagnetic waves areof 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 characterof electrical transmission through space(1888, in Karlsruhe, Germany, at thelocation of today’s University of Karlsruhe)CS 6471.26

History of wireless communication I 1896Guglielmo Marconi first demonstration of wirelesstelegraphy (digital!)long wave transmission, hightransmission power necessary ( 200kw)1907Commercial transatlantic connections huge base stations(30 100m high antennas)1915Wireless voice transmission New York - San Francisco 1920Discovery of short waves by Marconi reflection at the ionospheresmaller sender and receiver, possible due to the invention of the vacuumtube (1906, Lee DeForest and Robert von Lieben)1926Train-phone on the line Hamburg - Berlin CS 647wires parallel to the railroad track1.27

History of wireless communication II1928many TV broadcast trials (across Atlantic, color TV,TV news) 1933Frequency modulation (E. H. Armstrong) 1958A-Netz in Germany analog, 160MHz, connection setup only from the mobile station, nohandover, 80% coverage, 1971 11000 customers1972B-Netz in Germany analog, 160MHz, connection setup from the fixed network too (butlocation of the mobile station has to be known)available also in Austria, Netherland and Luxembourg, 1979 13000customer in D1979NMT at 450MHz (Scandinavian countries) 1982Start of GSM-specification goal: pan-European digital mobile phone system with roaming1983Start of the American AMPS (Advanced Mobile PhoneSystem, analog) 1984CT-1 standard (Europe) for cordless telephones CS 6471.28