Cellular concept part 1


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Cellular concept part 1

  1. 1. Mobile Communication SystemsyPart 1- Introduction & PrinciplesProfessor Z GhassemlooyProfessor Z GhassemlooySchool of Computing, Engineering andInformation SciencesSchool of Computing, Engineering andInformation SciencesUniversity of NorthumbriaU.K.University of NorthumbriaU.K.Prof. Z. Ghssemlooyhttp://soe.unn.ac.uk/ocrhttp://soe.unn.ac.uk/ocr
  2. 2. Reading List- Mobile and Data Communications Systems, D Wong, D Britland, Pub: Artech Housey , g, ,- Mobile Communications, A Jagoda, M DeVillepin, Pub: J. Wiley- Mobile Information Systems, Editor: J. Walker, Pub: Artech House- Introduction to Digital Mobile Communications, Y Akaiwa, Pub: J. WileyMobile Communications 2nd Ed J Schiller ISBN 0 321 12381 6- Mobile Communications, 2nd Ed, J Schiller, ISBN 0-321-12381-6- Wireless Communications & Networks – Stallings- Mobile Communications – Dr. J. Schiller- 3G Wireless Demystified - Hartey-Introduction to Telecommunications - Anu Gokhale- Mobile Communication Systems, Parsons J D and Gardiner J G, Blackie USA HalstedPressMobile Communications Engineering Lee William C Y McGraw Hill Inc- Mobile Communications Engineering, Lee, William C. Y., McGraw-Hill, Inc.- Mobile Cellular Telecommunications Systems, Lee, William C. Y., McGraw-Hill, Inc.Websites:Websites:- IEC Online Education- How Stuff works- Teracom Training InstituteProf. Z. Ghssemlooyg- Telecom Writing
  3. 3. ContentsFrequency BandHistory Part IyPrinciplesTransmission PropertiesTransmission PropertiesCellular ConceptT ffi E i iTraffic EngineeringPropagationModulationPerformanceProf. Z. Ghssemlooy
  4. 4. Frequency Bandsq yVHF (30 MH 300 MH )VHF (30 MHz - 300 MHz)VHF Mid B d (70 87 5 MH )– VHF Mid Band (70 - 87.5 MHz)– VHF High Band (148 - 174 MHz)UHF (300 MHz - 3 GHz)– UHF Band (403 - 420 MHz)– UHF Band (450 - 520 MHz)UHF Band (450 520 MHz)– UHF Band 900 MHz (820 - 960 MHz) ⎫– UHF Band 1.9 GHz (1880 - 1900 MHz) ⎫Prof. Z. Ghssemlooy( )
  5. 5. Mobile ServicesPrivate Mobile Radio (PMR) System ⎫ate ob e ad o ( ) Syste ⎫– Conventional Mobile Radio Systems• Simple two-way radio• Fixed frequency assignment• Fixed frequency assignment• Generally no privacy– Trunked Mobile Radio SystemsC ll l t k hit t• Cellular network architecture• Efficient use of the frequency spectrum• Intelligent radio equipmentCordless Telephone Systems (e.g. DECT)– Analogue Cellular Phone Systemsg y– Digital Cellular Phone Systems ⎫– Personal Communication SystemsProf. Z. Ghssemlooy– Mobile Data Services
  6. 6. Mobile Communications - Historyy1934 AM based: 1st Generation Analogue Cellular Systems1934-USAAM based: 1st Generation Analogue Cellular Systems- For public safety- 5000 mobiles- Vehicle ignition noise a major problem1935USAEFM based: - Frequency bands:- 800 - 900 MHz and 400 - 500 MHz- 120 kHz RF bandwidth channel spacing of 30 kHzEuropeAsia- 120 kHz RF bandwidth, channel spacing of 30 kHz- Data rate 5 - 10 kbps- No of channels 400 – 1000, half-duplex1946-USAFirst Generation Public Mobile Telephone Service:- Coverage distance: 50 km, 60 kHz bandwidthProf. Z. Ghssemlooy- Single powerful transmitter
  7. 7. History - 1st Generation (1G) Systemsy ( ) y1960 Cellular Radio, developed by Bell Labs., p y19 0 C ll l M bil S t (USA)1970 Cellular Mobile System (USA)1980 First Generation Analogue Cellular Systems- Advanced Mobile Telephone Systems (AMPS)- Advanced Mobile Telephone Systems (AMPS)- Frequency bands: 800 - 900 MHz and 400 - 500MHzCh l i 30 kH d f h l 400- Channel spacing 30 kHz and no of channels 400– 1000- Data rate 5 - 10 kbpsProf. Z. Ghssemlooyp-FM for speech, FSK for signalling, FDM
  8. 8. History - 2nd Generation (2G) Systems(1991 4)(1991-4)Systems:- 1991 First Group Special Mobile (GSM) network, Finland- 1992 Commercial GSM, all major European operators- 1992 Japanese Digital Cellular (JDC) system- 1993 GSM1800 system in commercial operation, UKy p ,- 1994 Commercial operation of D-AMPS (IS-54), US- U.S. Digital Cellular (USDC) and CDMA• Technology: TDMA, TDMA hybrid FDMATechnology: TDMA, TDMA hybrid FDMA• Characteristics:• Digital voice and low speed data• Frequency band @ 900 MHz, RF channel spacing 200 kHz• Modulation: GMSK, DPSK, Fixed frequency assignment• Speech rate 13 kbps, Speech coding, TDMA• High security and higher capacity,• Improved speech Quality of service (QoS)1. NEC Cellstar 500 series (1992)2. Nokia 2110 series (1994)3 N ki 5120 (1998)• Improved speech Quality of service (QoS)• GSM 1.8 GHz, and 1.9 GHzUSDC 1 9 GH3. Nokia 5120 (1998)4. Kyocera 2135 (2002)5. Audiovox CDM8300 (2002)6. Samsung SCH-A650 (2004)Prof. Z. Ghssemlooy• USDC 1.9 GHz• Digital Cordless Systems (DCS) 1.8 GHz
  9. 9. Current - 3rd Generation (3G) Systems(1995 )(1995 - )Support Multimedia Services:– Especially Internet Service, 144kb/s (Outdoor and higher velocity ),– 384kb/s(from outdoor to indoor) and 2Mb/s (indoor);– Speech of QoS and other servicesFirst Transitional System: 2 GHz2000 - 2nd Transitional Systems: 2.5 GHz2001 1st CDMA Network @ 144 k bps2001 - 1st CDMA Network @ 144 k bps2002- Handover between GSM and WCDMA by Nokia and Vodafone2003 Worlds 1st IPv6 over 3G UMTS/WCDMA network, Ericsson,2003 Worlds 1st CDMA2000 high-speed packet data phone call ( 3.09Mbps), Nokia2004 Worlds 1st Enhanced Datarate for Global Evolution2004, Worlds 1st Enhanced Datarate for Global EvolutionEDGE-WCDMA 3G packet data handover, Nokia and TeliaSonera2005, 9 Mbps with WCDMA, HSDPA phase 2, EricssonProf. Z. Ghssemlooy, p , p ,2005, 1.5 Mbps enhanced uplink WCDMA system, Ericsson
  10. 10. Current - 3G SystemsyAre referred to as:Are referred to as:Universal Mobile Telecommunications System (UMTS) inEuropeInternational Mobile Telecommunications 2000 (IMT2000)worldwide.“UMTS will be a mobile communications system that can offersignificant user benefits including high-quality wirelessmultimedia services to a convergent network of fixedmultimedia services to a convergent network of fixed,cellular and satellite components. It will deliver informationdirectly to users and provide them with access to new andinnovative services and applications It will offer mobileinnovative services and applications. It will offer mobilepersonalised communications to the mass marketregardless of location, network and terminal used”.Prof. Z. GhssemlooyUMTS Forum 1997
  11. 11. UMTS - Main Requirements (3 Ms)q ( )Multi-mediaMulti-environmentM lti t Vi t l tMulti-operator Virtual operatorsGlobalDifferent environments for UMTSSuburbanUrbanMicro-CellIn- BuildingH C llMacro-Cell Pico-CellHome-CellProf. Z. GhssemlooyH. Aghvami, KCL,UK
  12. 12. Mobile Telephony Standardsp yA C P id Wh t’ Will P idAccessStandardCompany Provides What’sComingWill ProvideCDMA / TIA Verizon Voice, Data, 1XEV-DO 300-500 kbps, to95 PTT, 1xRTT CDMA-2000 2.4 MbpsTDMA / TIA136Cingular /AT&TVoice, Data Edge 384 kbps data136 AT&TCDMA / PCS Sprint Voice, Data 1XEV-DV to 3.1 MbpsTDMA / iDEN Nextel Voice, Data,PTTSpectrumchangeAddress publicsafety concernGSM T-Mobile Voice Data GPRS W- 115 kbps dataGSM T Mobile,AT&TVoice, Data GPRS, WCDMA, PTT115 kbps dataProf. Z. GhssemlooySource: IEEE
  13. 13. Technologies - Multimedia MessagingService (MMS)Service (MMS)It d d iIt d d iIt send and receives:–Text messagesGraphics and PhotosIt send and receives:–Text messagesGraphics and Photos–Graphics and Photos–Audio, video clips–Graphics and Photos–Audio, video clipsMultimediaIt supports:–Image: GIF, JPEG,It supports:–Image: GIF, JPEG,MultimediaMessagingService Image: GIF, JPEG,–Video: MPEG4–Audio: MP3, MIDIImage: GIF, JPEG,–Video: MPEG4–Audio: MP3, MIDIService(MMS)For high transmission speed uses:3GFor high transmission speed uses:3GProf. Z. Ghssemlooy- 3G- GPRS: General Packet Radio Service- 3G- GPRS: General Packet Radio Service
  14. 14. Technologies - General Packet RadioService (GPRS)Service (GPRS)Packet based:– subs are always on line– easy and quick accessy qProvide high speed wireless Internet and datacommunicationscommunicationsSpeed four times higher than conventional GSMsystemssystemsProf. Z. Ghssemlooy
  15. 15. Technologies - BluetoothgShort range RF technologyA global standardNo wiringData and voice communicationsOffers ad hoc network and synchronicity between allpersonal devicespersonal devicesProf. Z. Ghssemlooy
  16. 16. Mobile Computingp gApplicationsInterfaceConsiderationsCommunications,Connectivity andNetworkInfrastructureUsabilityIssuesSystemsDataRepositories/InfrastructurePersistent StorageProf. Z. GhssemlooySystemsIntegration DatabaseSystemsPersistent StorageMedia
  17. 17. Number of mobile phone subscribers inUKUKhttp://www.mobilemastinfo.com/information/history.htmProf. Z. Ghssemlooy
  18. 18. Mobile Internet OutlookMillions1,400Projectedcellular1,4001,200More handsets than PCscellularsubscribers(Nokia 1999)1,000connected to the Internet by theend of 2003 !Projected Web800600Projected Webhandsets(Nokia 1999)400 Projected PCsconnected tothe Internet2000the Internet(Dataquest 10/98)Prof. Z. Ghssemlooy1996 1997 1998 1999 2000 2001 2002 2003 2004 20050
  19. 19. Mobile Network in UK5 network operators45,000 base station sites.2/3 i t ll d i ti b ildi t t2/3 are installed on existing buildings or structures.< 2% are mounted on schools.Additional mobile phone base stations will need tobe built to support 3G services. It is possible that thenumber of base station sites will rise to 50,000 byProf. Z. Ghssemlooy2007.
  20. 20. Mobile Communications - DefinitionDesigned to operate over a very large area with aDesigned to operate over a very large area with alimited bandwidthA cellular mobile comms system uses a large numberA cellular mobile comms. system uses a large numberof low-power wireless transmitters (100 W oe less)Off l it th h ll littiOffers larger capacity through cell splittingVariable power levels allow cells to be sized accordingto subscriber density& demand within a particular regionAs mobile users travel from cell to cell theirAs mobile users travel from cell to cell, theirconversations are handed off between cellsChannels (frequencies) used in one cell can be reusedProf. Z. Ghssemlooyin another cell some distance away
  21. 21. Mobile Communications - PrinciplespWave propagation mechanism is closely affected by thewavelengths of the propagating frequencyUses a separate radio channel to talk to the cell siteC ll it t lk t bil t iCell site talks to many mobiles at once, using onechannel per mobileChannels use a pair of frequencies for:• forward link for transmitting from the cell siteli k f th ll it t i ll f th• reverse link for the cell site to receive calls from the usersRadio energy dissipates over distance so mobiles mustRadio energy dissipates over distance, so mobiles muststay near the base station to maintain communicationsBasic structure of mobile networks includes telephoneProf. Z. Ghssemlooypsystems and radio services
  22. 22. Mobile Communs. - Cellular SpectrumPhone TransmitA band10 MHzB band10 MHz825 835 845824 846.5 849A”bA’bB’b333 channels30kHz333 channels30kHzbandandand1 MHz 1.5 MHz 2.5 MHz33 chs 50 chan 83 chs20 MHz Guard870 880 890869A band B bandBase Transmit891.5 894AA band10 MHz333 channels30kHzB band10 MHz333 channels30kHzA”bandA’bandB’bandProf. Z. Ghssemlooy1 MHz33 chan1.5 MHz50 chs2.5 MHz83 chs
  23. 23. Mobile Comms. - Systemy• Mobile Unit• Mobile Base Station• Mobile Switching CentreProf. Z. GhssemlooyMobile telecommunicationsswitching office (MTSO)
  24. 24. Mobile Comms. - ComponentspMobile Base Station (MBS): includesMobile Base Station (MBS): – includes– an antenna,– a controller,a controller,– a number of receiversMobile telecommunications switching office (MTSO)– connects calls between mobile unitsChannels between mobile unit and MBSC t l h l t h i f ti l t d t tti– Control channels: to exchange information related to setting upand maintaining calls– Traffic channels: to carry voice or data connection betweenyusersProf. Z. Ghssemlooy
  25. 25. MTSO Controlled Call between MobileUsersUsersSteps:-Steps:-Mobile unit initializationMobile originated callMobile-originated callPagingC ll t dCall acceptedOngoing callH d ffFunctions:-Handoff Call blockingCall terminationCall droppingCalls to/from fixed and remoteProf. Z. Ghssemlooymobile subscriber
  26. 26. Mobile Radio EnvironmentP ti P th LPropagation Path LossMultipath FadingFrequency-Selective FadingDoppler ShiftppCo-Channel InterferenceAdjacent Channel InterferenceAdjacent Channel InterferenceMan-Made NoiseUrban EnvironmentUrban EnvironmentSuburban EnvironmentR l E i tProf. Z. GhssemlooyRural Environment
  27. 27. System CharacteristicsyFrequency sharing amongst usersM lti th i t f i tMultipath interference environmentLine-of sight coverage (UHF)High base station antenna (30m)Low mobile antenna (1 5m - 3m)Low mobile antenna (1.5m - 3m)Beyond Line-of-sight (VHF)Long distance (HF)Prof. Z. Ghssemlooy
  28. 28. Early Mobile Systemsy yTraditional mobile similar to TV broadcastingTraditional mobile similar to TV broadcastingOne very powerful transmittery plocated at the highest spotwould cover an area with adi f t 50 kradius of up to 50 kmCellular concept re-structured the mobile telephonenetwork in a different way:network in a different way:• Using low power transmitters to cover larger area.E g dividing a metropolitan region into 100 different cellsProf. Z. GhssemlooyE.g. dividing a metropolitan region into 100 different cells12 channels each
  29. 29. Digital Cellular- what does it offers?gBest quality compared with analogue systemImproved bandwidth efficiencyImproved bandwidth efficiency- Reduced from 30 kHz to 10 kHz, and then to 5 kHz.This is achieved via 3-time-slot Time Division Multiple Access(TDMA) (i.e. three pairs of people using a 30 kHz radiochannel simultaneously)Use of micro-cellular technology to accommodate smaller andsmaller cells particularly around the new frequency bandf 2 GHof 2 GHzImproved frequency reuseProf. Z. GhssemlooyImproved frequency reuse
  30. 30. Transmission TypesypfSimplexf1f2f1Tx : f1Rx : ff1f2Rx : f2Tx Rxf fTx : f1Rx : f2Tx Rxf2 f12Half DuplexProf. Z. GhssemlooyTx : f1, Rx : f1f1 f1
  31. 31. Transmission Types - Full Duplexyp pf1 f3f fTx : f1R fTx : f3R ff4f3f2f1f2 f4Rx : f2 Rx : f4RxTxTxRxProf. Z. Ghssemlooy
  32. 32. Transmission - Duplex Operationp pf1 f2RxRx((ff )) Antennaf1 f2F((ff11))DupDupAntennaF1TxTx((ff ))MMf2((ff22))TLoadTx LoadReceptionTxLoadProf. Z. GhssemlooyRxAntenna Transmission RxAntenna
  33. 33. Typical Wide-Area Systemyp yDispatcherDispatcherDi it lDispatcher2DigitalSwitchDispatcherDispatcher11-- Dispatcher: Communicates with the vehicles.Dispatcher: Communicates with the vehicles.C i ti d H lf D lC i ti d H lf D lProf. Z. Ghssemlooy-- Communication mode: Half Duplex.Communication mode: Half Duplex.-- MobileMobile--toto--mobile communication is possible using a Talkmobile communication is possible using a Talk--Through Repeater (halfThrough Repeater (half--duplex) orduplex) ordirect using Simplex mode.direct using Simplex mode.
  34. 34. Mobile Transmission EnvironmentDeep Radio Shadow + Radio HorizonDeep Radio Shadow + Radio HorizonReflection, Refraction and ScatteringFadingFading– Frequency-Selective– MultipathPropagation Path Loss (Attenuation)Doppler ShiftDelay DistortionyNoise and InterferenceUrban Suburban and Rural EnvironmentsProf. Z. GhssemlooyUrban, Suburban, and Rural Environments
  35. 35. Transm. Pro. - Deep Radio ShadowpRadio waves at low frequencies can diffract (bend) around object quit• Radio waves at low frequencies can diffract (bend) around object quitwell• In mobile systems (high frequency band), wave diffraction does nottake place well, therefore a deep radio shadow occurs on the un-illuminated side of the obstruction (e.g., building, hill, truck, or evenhuman being)shadowhuman being)shadowTProf. Z. GhssemlooyTx
  36. 36. Transm. Env. - Radio Horizon (1/2)• Is 30% farther from the transmitting antenna than theequivalent visible horizon due to the reduction of therefraction in the upper atmosphere as compared to thatt d l lat ground level.Beyond radio horizon the signal strength falls very rapidlyBeyond radio horizon, the signal strength falls very rapidlyso that in areas well beyond the horizon the same frequencycan be reused without causing interference.g• The higher the transmitter antenna the further away isThe higher the transmitter antenna, the further away isits radio horizon.Prof. Z. Ghssemlooy
  37. 37. Transm. Env. - Radio Horizon (2/2)The coverage area (not the radius) is approximatelyproportional to the antenna heights of both transmitterand receiverand receiver.With a higher transmitter tower the far flung horizonWith a higher transmitter tower, the far flung horizonprevents close reuse of the same frequency.Between the transmitter and horizon in open flatBetween the transmitter and horizon, in open, flatcountry, the received power reduces approximatelyas the inverse fourth power of distance from thetransmitter (as we see later on).Prof. Z. Ghssemlooy
  38. 38. Transmission Env. – contd.EiReflection at large obstaclesiEr= α Ei, where α is the absorption coefficient < 1EiScattering at small obstacles Er1= α EiE 2= α EiEr2 α EiErk= α EiE 1= α EDiffraction at edgesEiEr1 α EiEr2= α EiProf. Z. GhssemlooyDiffraction at edges
  39. 39. Transm Env – MultipathTransm. Env. – MultipathDispersionsignal at TxDispersionDistortionsignal at Txsignal at receiverDispersion: signal is dispersed over time, thus interfering with“neighbor” symbols --> Inter Symbol InterferenceDistortion: signal reaches a receiver directly and phaseshifted:- distorted signal depending on the phases of thedifferent partsProf. Z. Ghssemlooydifferent parts
  40. 40. Transm. Pro. – Multipath Fadingp gIn a multipath propagation environment signal are:In a multipath propagation environment signal are:- Generally added to strengthen the received signal- At some point they subtract from one another, thus causingfading, (at approximately half wavelength intervals).- The fade power level is typically 20 dB weaker than the localaverage field strength. Fades that are 40 dB weaker are notuncommon.- The combination of shadowing and multipath fading resultsin a radio field that varies wildly over a short ranges (up to60 or 70 dB difference between the maximum and minimumt t l l l ithi 100 2)Prof. Z. Ghssemlooystreet level value within a 100 m2).
  41. 41. Transm. Env. - Attenuation• The strength (amplitude) of the signals reduces as it• The strength (amplitude) of the signals reduces as itpropagate through the channel. This is called signalattenuation or loss, which is due to:,• Absorption of energy• Scattering of energy• Limits the maximum coverage distance.• Can be overcome by in line amplification.Can be overcome by in line amplification.High frequencies penetrates building fairly well, mostlyth h d i d d thi t lli fHigh frequencies penetrates building fairly well, mostlyth h d i d d thi t lli fthrough doors, windows, and thin non-metallic roofs.Typical mean building penetration losses are 10 to 20dB, but penetration losses as high as 40 dB have beenthrough doors, windows, and thin non-metallic roofs.Typical mean building penetration losses are 10 to 20dB, but penetration losses as high as 40 dB have beenProf. Z. GhssemlooydB, but penetration losses as high as 40 dB have beenencountered.dB, but penetration losses as high as 40 dB have beenencountered.
  42. 42. Transm. Env. - Bandwidth• All real channels have a limited bandwidthAll real channels have a limited bandwidth.• Not all the frequency components of transmitted signalwill pass through the channel.• At the receiver, exact regeneration of the original signalAt the receiver, exact regeneration of the original signalbecomes quite difficult.• Resulting in the received signal distortion• Resulting in the received signal distortionProf. Z. Ghssemlooy
  43. 43. Transm. Pro. - Delay Distortiony• Critical in complex waveform transmission, such as DigitalSignals, where different frequency components of thesame signal travel at slightly different speedssame signal travel at slightly different speeds.• As the propagation link increases, fast components of onebit (edges) may eventually catch up the proceeding slow( g ) y y p p gmoving components of the bit (flat top). Thus resulting indistortion.Prof. Z. Ghssemlooy
  44. 44. Transm. Pro. - Noise & Interference. Thermal noise. Amplifier noiseRFRF + NoiseReceiverReceiverRFsignal. Man made noise. Inter-modulation: noise from other transmitters at differentfrequencies. Co-channel interference: noise from other transmitter at the samefrequencyProf. Z. Ghssemlooyfrequency. Electromagnetic interference in a vehicle
  45. 45. Mobile Phones Technology -DisadvantagesDisadvantagesAlthough the development of mobile phones brought convenient andAlthough the development of mobile phones brought convenient andadvantages to the world. But the disadvantages brought along withthe fast grown technology cannot be ignored. These problems notonly influenced people personally but also the society at largeonly influenced people personally but also the society at large.Symptoms caused by the radiation of mobile phones are:– headache, earaches, blurring of vision and even causing cancerThough, these problems are still under research. Mobile phoneusers are advice to reduce the usage on mobile phones if it ispossible.pMobile phone addiction.– Mobile phone addiction is becoming one of the biggest non-drugaddictions in the 21st century in particular among the teenagersaddictions in the 21st century in particular among the teenagers.– New models of mobile phones are released almost everyday. In orderto get up-to-date, people tend to change their mobile phones once ina while These became habits among the mobile phone users causingProf. Z. Ghssemlooya while. These became habits among the mobile phone users causingthem to spend unnecessary cost on mobile bills and
  46. 46. Mobile Phone Technology - FutureDevelopmentDevelopmentMobile phones are getting more and more sophisticatedMobile phones are getting more and more sophisticated,just like computerThe technology is growing everyday with different functionsand usageFrom the network system from mobile phones, it is stilldevelopingdeveloping.– The new 3G system had just been launched not long ago,– 4G system expected in 2010. It is expected that the 4Gsystem will be able to deliver• a much faster speed up to 100Mb per second during connection,• tighter network security• High quality during communication no matter on voice or video calls.• security system, and surveillance on certain items. The 4G system will beexpected to be launched in 2010.Prof. Z. Ghssemlooy
  47. 47. Mobile Phone Technology - FutureDevelopmentDevelopmentMobile phone, the piece of communication deviceitself is also becoming a multi functioned device.S t h d PDA h l dSmartphones and PDA phones are alreadylaunched in the market.M bil h ith ti f ti l iMobile phone with computing functions replacinglap-topsProf. Z. Ghssemlooy
  48. 48. SummaryyHistoryMobile technologiesPrincipleCharacteristicsTransmission propertiesProf. Z. Ghssemlooy
  49. 49. Next LectureCellular ConceptCellular ConceptProf. Z. Ghssemlooy