Mobile Communication introduction lecture.pdf

cellular Communication

1. Dr. Ahmed M. AbdEl-Haleem
Mobile Communication
Fall 2022/23
Cellular Communication
Introduction
Faculty of
Engineering

2. Dr. Ahmed M. Abd El-Haleem
Associate Professor in
Communication and Electronic Department
Faculty of Engineering, Helwan University
E-mail: [email protected]
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3. Course Assessment Plan
3
Mid-Term Grade
Research project 10%
Written Exam 20%
Assignments 10%
Final Written Exam 60%

4. Wireless Communication System
4
Passband
Transmitter Channel Receiver
Wireless
Transmission
media
Source information
Input sensor Output sensor
Destination information
Passband
Passband
Baseband
Message
Baseband
Message
▪Path loss and shadowing
▪Self interference
oMultipath [Rayleigh] fading
oDelay Spread: Intersymbol
interference (ISI)
oDoppler Shift [due to motion]
▪Noise (SNR)
▪Other users
oCo-channel interference (CCI)
oAdjacent-channel interference (ACI)

5. Signal-to-Noise Ratio and Shannon Capacity
5





+=
N
S
BC 1log
2
▪Signal-to-NoiseRatio(SNR)
oS/N=SNR= signal power(Watt)/noise power(Watt)
oS/N(dB)=SNR(dB)= 10 log
10(S/N power ratio)
oSNR relate to the performance of communication systems
oBit Error Rate (BER)
oShannon Capacity (System Capacity in bits/s)

6. Signal-to-Noise Ratio and Shannon Capacity
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▪Signal-to-InterferenceRatio(SIR)
oSometimesknownasC/I(carrier-to-interferenceratio)
oInterference: signals from other simultaneous
communications
oS/I=SIR= signal power(Watt)/Interference power(Watt)
▪Signal-to-Interference-plus-Noise-Ratio(SINR)
oSINR= signal power(Watt)/(Interference power(Watt) +
noise power(Watt))
▪ShannonCapacityforWirelessCommunicationChannel
oTheoretical (upper) bound of communication channel
capacity
oConsider a bandlimited Gaussian channel operating in
the presence of additive Gaussian noise.

7. Signal-to-Noise Ratio and Shannon Capacity
7
oTheShannon-Hartleytheoremstatesthatthe
channelcapacityisgivenby
C = B log2(1 + SNR)
oC is the capacity in bits per second (bits/s).
oB is the bandwidth of the channel in Hz.
oSNR is the signal-to-noise ratio.

8. Signal-to-Noise Ratio and Shannon Capacity
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▪How to evaluate the performance of a communication
scheme?
oHow close to Shannon bound?
oSpectral efficiency (bits/s/Hz)

9. Transmission modes in wireless Com. Systems
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1) Simplex RF Communication Systems
Aradiotechnologythatallowsonlyone-waycommunicationfroma
transmittertoareceiver.
Examples:FMradio,Pagers,TV,AdaptiveMulti-Rate(AMR)systems.

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2) Half-duplex RF Communication Systems
Two-waycommunicationbutnotsimultaneous(Push-to-talk)Time
DivisionDuplex(TDD).
Useanydesiredfrequencychannelfortransmitterandreceiver.
Sendtransmitandreceivesignalsatdifferenttimes.
Examples:Walkie-talkie.
Transmission modes in wireless Com. Systems

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3 Full-duplex Communication Systems
Two-waycommunicationSimultaneous.
Separatefrequencychannelsintotransmitandreceive
bandsAllowssimultaneoustransmissionandreception.
Examples:Cellularphones,satellitecommunication.
Transmission modes in wireless Com. Systems

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3 Full-duplex wireless Communication Systems
FrequencyDivisionDuplex(FDD)andTimeDivision
Duplex(TDD)isusedtoallowforsimultaneous
transmissionandreception
Transmission modes in wireless Com. Systems

13. Multiple Access Techniques
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We Have a capacity as shown in Fig. so How
can we divide it between users.
Power as function of time and frequency.

14. Multiple Access Techniques (Cont’d)
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1) Frequency Division Multiple Access (FDMA)
Eachusergetsafrequencyslotthathecanuseallthetime
withhighpower.
Thesefrequencybandsarenon-overlappingandaguardspaceis
usedbetweentheadjacentfrequencybands.
Thismultipleaccesstechniqueisveryhelpfuliftheusersare
communicatingwithinthesamegeographicalareaorspace.

15. Multiple Access Techniques (Cont’d)
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1) Frequency Division Multiple Access (FDMA)
▪Advantages of FDMA
oItissimpletoimplement.Thereceiveronly
needstotunetotheparticularfrequencyto
receivethedata.
oManynetworkscanworkwithinthesamespace
andatthesametime.
oEachuserhasitsownsub-channel,soheorshe
canusethefullcapacityofthesub-channel.
oNointerferencefromtheadjacentfrequencies.

16. Multiple Access Techniques (Cont’d)
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1) Frequency Division Multiple Access (FDMA)
▪DisadvantagesofFDMA
oCapacityintermsofchannelavailabilityislow.
Afterthechannelbeingallocatedtoauser,the
usercanusethechannelforalongtimeof
his/herwill.Incaseofhightrafficthenewusers
needtowaituntilthechannelisfree.
oDuetoguardbandbetweentheadjacent
frequencies,theoverallbandwidthutilizationis
poorbecausewearewastingsomefrequencies.I
meantheguardbandisnotallocatedtoanyuser.

17. Multiple Access Techniques (Cont’d)
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2) Time Division Multiple Access (TDMA)
•Eachusergetsatimeslotwherehecanuseallthefrequencywith
highpower.
•Itsmeanmultipleusersareusingthesamefrequencybutin
differenttimeslots.
•Theguardspaceinatimedomainisalsoneededwhichisknownas
timegap.
•Iftwousersoverlapintimethisiscalledco-channelinterference.

18. Multiple Access Techniques (Cont’d)
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2) Time Division Multiple Access (TDMA)
▪AdvantagesofTDMA
oOneAdvantageofTDMAoverFDMAisthatsingle
frequencycanbeusedbymanyusers.Soifmoreusers
arecoming,youcanincreasethetimeslotsandallocate
themthesamefrequency.Butrememberthereisalways
alimitednumberoftimeslotsareavailableinevery
application.
oDuetotimegap,nointerferencefromadjacent
transmissions.
oNofrequencyguardbandisneededsoyoucanuseallthe
frequencies.

19. Multiple Access Techniques (Cont’d)
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2) Time Division Multiple Access (TDMA)
▪DisadvantagesofTDMA
oEveryuserneedsaprecisesynchronization,otherwisea
usercancreateco-channelinterference.Onthereceiver
sideausermustreceivethedataatexactlythesametime.
oBecausethechannelisavailableforsmallamountoftime,
thisreducestheoveralldatarate.

20. Multiple Access Techniques (Cont’d)
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3) Code Division Multiple Access
A user gets all the time and uses all the frequency range but
uses only a part of the power (through the use of codes).
These codes are orthogonal to each other so the guard space is
achieved in code domain between the users using the same
channel simultaneously.

21. Multiple Access Techniques (Cont’d)
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3) Code Division Multiple Access
▪AdvantagesofCDMA
oMoreflexibilityintermsofcodesascomparedto
frequenciesinFDMAsystem.
oOnlyonefrequencybandcanbeusedbymultipleusersall
thetime.
oCodesareorthogonaltoeachothersoInterferenceis
minimum.
▪DisadvantagesofCDMA
oReceiverneedstoknowthecodeandprecise
synchronizationisrequired.
oAsalltheusersarecommunicatingatthesamefrequency,a
nearusertransmittingathigherpowercandamage
informationforothernearbyusers

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4) Space Division Multiple Access (SDMA)
In SDMA, different channels are separated by a large
enough distance so they can’t interfere with each other.
Multiple Access Techniques (Cont’d)

23. Evolution of Mobile Communication Systems
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24. Evolution of Mobile Communication Systems
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25. Evolution of Mobile Communication Systems
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1960EarlyMobileorZeroGeneration(0G)Mobilesystem
In1960acarMobileTelephone(MTA)systemwaslaunchedinSweden.
Theradiotelephonesystemcontained:
❖Composedofvacuumtubes→
weightof40kg
❖Radiotelephonesaretypically
mountedincars,trucks,….
❖Radiophoneshaveapowerful
transmitter→upto80Km.
❖Onecentralantennatowerper
region.
❖Limitednumberofavailable
channels→limitednumberof
radiotelephonesperregion.

26. Evolution of Mobile Communication Systems
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1979FirstGeneration(1G)Mobilesystem
Thefirstcommerciallyautomatedcellularnetworkwas
launchedinJapanbyNipponTelegraphandTelephone
(NTT)in1979.
InEurope→NordicMobileTelephony(NMT).
InUK→TotalAccessCommunicationSystem(TACS).
❑InAmerica→AdvancedMobilePhone
Service(AMPS).

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1979FirstGeneration(1G)Mobilesystem
AMPShadthefollowingspecifications:
❖UseCellularConcepttoprovideservicetoageographicarea
❖Operatesinthe800-MHzband.
❖AnalogVoicecommunicationsusingFM
❖DigitalControlchannelsforsignaling
❖FDMA/FDDsystems
❖FrequencyReuse
❖Handoff/Handover
❖AdjustableMobilePowerlevels
❖MacroCells:1-40kmradius.
❖Theywerebasedondifferentstandardsso:incompatible
witheachother,limitedcapacityanddidnotsupport
roaming.
1.1 History of Mobile communication: 1G

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1982-1992SecondGeneration(2G)Mobilesystem(GSM)
In1982→Grouptodevelopastandardforamobile
telephonesystem,
GlobalSystemforMobile(GSM),thatwouldoperateinthe
900MHzbandwidth.
Evolution of Mobile Communication Systems

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1982-1992SecondGeneration(2G)Mobilesystem(GSM)
In1983(DigitalAMPS)D-AMPS
isapacket-switcheddataservice.
usestheexistingAMPSnetworktotransmitdataata
rateof19.2kb/s.
In1990,agroupof15operatorsfromacrossEurope
implementedGSM900.
ThefirstcommercialGSMnetworkwaslaunchedinJune,
1992inGermany.
Evolution of Mobile Communication Systems

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1982-1992SecondGeneration(2G)Mobilesystem
(GSM)
ThesecondgenerationGSMhasthefollowing
specifications:
❖Usedigitaltechnologyandapplycellularconceptand
Circuitswitching.
❖Frequencyband(900,1800,1900MHz)andSupport
internationalroaming.
❖FDMA-TDMA/FDD →(8timeslot/Carrier)→(Limited
capacity).
❖Application(Voice,SMS,Data)→(Limitedno.of
services).
❖Limiteddatarate=9.6Kbps→(Low).
Evolution of Mobile Communication Systems

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1994-1998SecondGeneration(2.xG)Mobilesystem
Supporttheuseofinternetappsonmobiles,using
WirelessApplicationsProtocol(WAP).
2.5Gstandardswereintroducedtoallow2Gequipmentto
bemodifiedanduserstationstobeSWupgraded
1)HighSpeedCircuitSwitchedData(HSCSD)→2.5G-GSM.
❖Increasesthedatarateto14.4Kbps,ascomparedto
theoriginal9.6KbpspertimeslotintheGSM.
❖Usingupto8consecutivetimeslotsachievesraw
transmissionrateofupto115.2kbps
Evolution of Mobile Communication Systems

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2)GeneralPacketRadioService(GPRS)→2.5G-GSM.
❖Increasestheavailabledatarateto21.4Kb/sperslot.
whenusingall8timeslots=171.2kb/s.
❖PacketswitchingsuchasanInternetconnection.
❖GPRS uses a new channel coding methods are used that
provide higher payload rates per time slot.
❖GPRSoffersanumberofcodingschemeswithdifferent
FEClevelsoferrordetectionandcorrection,dependingon
theradiochannelconditionsandtherequirementsforthe
databeingsent.
❖ImplementationofGPRSrequirestheGSMoperatorto
installnewrouters,internetgatewaysattheBS,andnew
SWthatredefinestheBSGPRSairinterfacestandard.
Evolution of Mobile Communication Systems

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3)EnhanceDatarateforGSMEvolution(EDGE)is
sometimesreferredtoasEnhancedGPRS,orEGPRS.
❖RequirestheadditionofnewHWandSWatexistingBSs.
Itintroducesanewdigitalmodulationformat,8-bitPhase
ShiftKeying(8-PSK),whichisusedinadditiontoGSM’s
standardGaussianMinimumShiftKeying(GMSK)
modulation.
❖EDGE+8-PSKmodulation+8timeslots➔arawpeak
throughputdatarateof473.6kb/s.Practically,only384
kb/scanbeachievedforasingleuser.
❖ThereareninedifferentModulationandCodingSchemes
(MCS)thatcanbeusedwithEDGE.
Evolution of Mobile Communication Systems

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1999ThirdGeneration(3G)Mobilesystem(UMTS)
TheInternationalTelecommunicationUnion(ITU)defined3G
systemasbeingcapableofsupportinghighspeeddataranges
from144kb/stogreaterthan2Mb/s.
The3GevolutionforGSMandIS-136systemsleadsto
WidebandCDMA(W-CDMA),alsocalledUniversalMobile
TelecommunicationsSystem(UMTS)andthathasthefollowing
specifications:
❖Largenetworkcapacity
❖VoiceOverInternetProtocol(VOIP)
❖Multimediacommunications
❖Circuit-switchedandpacket-switched-basedservices
❖Improvedspectralefficiency
❖packet-basedairinterface➔userssharethesamewireless
networkandstayconnectedtotheInternet,anytime,
anywhere.
Evolution of Mobile Communication Systems

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2005ThirdGeneration(3.xG)Mobilesystem
High-SpeedPacketAccess(HSPA)
High-SpeedDownlinkPacketAccess(HSDPA)isan
enhanced3Galsodubbed3.5G.Itsupportsdatarate
of14.0Mb/s
High-Speed UplinkPacketAccess(HSUPA)
enhancestheuplinkrateto5.76Mb/sknownas
3.75G.
HSPA+supportsMIMOwhichincreaserateto42
Mb/s
Evolution of Mobile Communication Systems

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2008FourthGeneration(4G)Mobilesystem(LTE)
LongtermEvolution(LTE)isactuallya3.9Gtechnology.
LTEhasthefollowingspecifications:
❖Largenetworkcapacity
❖Downlinkpeakratesofatleast100Mbps
❖Anuplinkofatleast50Mbps
❖Videoconferencing
❖VoiceOverIP(VOIP)
❖Greatermobilityandlowcost
Evolution of Mobile Communication Systems

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2006FourthGeneration(4G)Mobilesystem(LTE)
▪LTE-Advanced(LTE-A)
oFasterbroadband
oHighercapacity
oFlexiblesupportforwiderchannels(upto100
MHz)
oMoreantennas(MIMO)
oChannelaggregationforhigherdatarates
oPeakdatarate1Gbps/500Mbps
oLowlatencies
Evolution of Mobile Communication Systems

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FifthGeneration(5G)Mobilesystem
Evolution of Mobile Communication Systems

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Evolution of Mobile Communication Systems