5. BRIEF HISTORY
First telephone (photo phone) –Alexander Bell, 1880
The first car mounted radio telephone –1921
1946 –First commercial mobile radio-telephone service by Bell and AT&T in Saint Louis, USA. Half duplex(PTT)
1973 –First handheld cellular phone –Motorola.
1982„GroupeSpécialMobile”iscreatedwithinCEPT(ConférenceEuropéennedesPostesetTélécommunications)
1987MainRadiotransmissiontechniquesarechosen, basedonprototypeevaluation(1986)
1989GSMbecomesanETSItechnicalcommittee
1990ThePhaseIGSM900specificationarefrozen
DCS1800adaptationstarts
1991Firstsystemsarerunning
DCS1800specificationsarefrozen
1992AllmajorEuropeanGSM900operatorsbegincommercialoperations(2G)
20003Gsystemcomesintomarket.
20104Gsystemcomesintomarket.
6. GLOBAL SYSTEM FOR MOBILE COMMUNICATION
GSMisastandarddevelopedbytheEuropeanTelecommunicationsStandardsInstitute(ETSI)todescribeprotocolsforsecond-generation(2G)digitalcellularnetworksusedbymobilephones.Asof2014ithasbecomethedefaultglobalstandardformobilecommunications-withover90%marketshare,operatinginover219countriesandterritories.
2Gnetworksdevelopedasareplacementforfirstgeneration(1G)analogcellularnetworks,andtheGSMstandardoriginallydescribedadigital,circuit- switchednetworkoptimizedforfullduplexvoicetelephony.Thisexpandedovertimetoincludedatacommunications,firstbycircuit-switchedtransport, thenbypacketdatatransportviaGPRS(GeneralPacketRadioServices) andEDGE(EnhancedDataratesforGSMEvolutionorEGPRS).
Subsequently,the3GPPdevelopedthird-generation(3G)UMTSstandardsfollowedbyfourth-generation(4G)LTEAdvancedstandards,whichdonotformpartoftheETSIGSMstandard.
GSMFunctions
Transmission.
Radio Resources management (RR).
Mobility Management (MM).
Communication Management (CM).
Operation, Administration and Maintenance (OAM).
10. MOBILE STATION (MS)
AMobileStationconsistsoftwomainelements:
Themobileequipmentorterminal.
Therearedifferenttypesofterminalsdistinguishedprincipallybytheirpowerandapplication:
The`fixed'terminalsaretheonesinstalledincars.Theirmaximumallowedoutputpoweris20W.
TheGSMportableterminalscanalsobeinstalledinvehicles.Theirmaximumallowedoutputpoweris8W.
Thehandhelsterminalshaveexperiencedthebiggestsuccessthankstotheweightandvolume, whicharecontinuouslydecreasing.Theseterminalscanemitupto2W.Theevolutionoftechnologiesallowstodecreasethemaximumallowedpowerto0.8W.
TheSubscriberIdentityModule(SIM).
TheSIMisasmartcardthatidentifiestheterminal.ByinsertingtheSIMcardintotheterminal, theusercanhaveaccesstoallthesubscribedservices.WithouttheSIMcard,theterminalisnotoperational.
SIM has microprocessor and memory, IMSI,
Authentication Key, Ki
Security Algorithms:kc,A3,A8
PIN & PUK
FunctionofMS:
Voice and data transmission & receipt
Frequency and time synchronization
Monitoring of power and signal quality of the surrounding cells
Provision of location updates even during inactive state
11. THE BASE STATION SUBSYSTEM (BSS)
TheBSSconnectstheMobileStationandtheNSS.Itisinchargeofthetransmissionandreception.TheBSScanbedividedintotwoparts:
TheBaseTransceiverStation(BTS)orBaseStation.
TheBTScorrespondstothetransceiversandantennasusedineachcellofthenetwork.ABTSisusuallyplacedinthecenterofacell.Itstransmittingpowerdefinesthesizeofacell.EachBTShasbetweenoneandsixteentransceiversdependingonthedensityofusersinthecell.
TheBaseStationController(BSC).
TheBSCcontrolsagroupofBTSandmanagestheirradioresources(upto100BTSs).ABSCisprincipallyinchargeofhandovers,frequencyhopping,exchangefunctionsandcontroloftheradiofrequencypowerlevelsoftheBTSs.
12. BASE TRANSCEIVER STATION (BTS) OR BASE STATION (BS)
Provides the radio links with the mobile station & BSC…
RF resources such as frequency assignments, sector separation, transmit power control
BTS connects to BSC through un-channelized T1 facilities or direct cables in co-located equipment (Abis)
The protocols are proprietary and are based on High-level data link control (HDLC)
Typically terminates the IS-2000 LAC/MAC protocols for common channels, although in some implementations such protocols are terminated at the BSC
In case of dedicated channels, the BTS exchanges physical layer frames with the BSC over Abisinterface
Typically equated to the physical site of the wireless network where antennas are located
3-cell BTS configuration is most common (max. up to 6 cell BTS)
13. OPERATION RANGE OF CELL TOWER
Heightofantennaoversurroundingterrain(Line-of-sightpropagation).
Thefrequencyofsignalinuse.
Timinglimitationsinsometechnologies(e.g.,GSMislimitedto35km,with70kmbeingpossiblewithspecialequipment)
Thetransmitter'sratedpower.
Therequireduplink/downlinkdatarateofthesubscriber'sdevice.
Thedirectionalcharacteristicsofthesiteantennaarray.
Reflectionandabsorptionofradioenergybybuildingsorvegetation.
Itmayalsobelimitedbylocalgeographicalorregulatoryfactorsandweatherconditions.
GSM,haveafixedmaximumrangeof35kilometers(22mi)
CDMAandIDENhavenobuilt-inlimit,butitispossibletogetbetween50to70km(30–45miles)
14. FUNCTIONS OF BTS
Radio resources
Signal Processing
Signaling link management
Synchronization
Local maintenance handling
Functional supervision and Testing
Controls the radio link
encryption
error control
signal strength
16. CONT…
BTS has three levels;
a)Antenna coupling level (ANC)
b)Trans receiver level (TRX)
c)Base station control function level (BSF)
BTSisalsoreferredtoastheradiobasestation(RBS),nodeB(in3GNetworks)or,simply, thebasestation(BS).FordiscussionoftheLTEstandardtheabbreviationeNBforevolvednodeBiswidelyused.
17. GENERAL ARCHITECTURE OF BTS
ABTSinhasthefollowingparts:
Transceiver(TRX)Quitewidelyreferredtoasthedriverreceiver(DRX),DRXareeitherinformofsingle(sTRU),double(dTRU)oracompositedoubleradiounit(DRU).Itbasicallydoestransmissionandreceptionofsignals.Italsodoessendingandreceptionofsignalstoandfromhighernetworkentities(likethebasestationcontrollerinmobiletelephony).
Poweramplifier(PA)AmplifiesthesignalfromDRXfortransmissionthroughantenna;maybeintegratedwithDRX.
CombinerCombinesfeedsfromseveralDRXssothattheycouldbesentoutthroughasingleantenna.Allowsforareductioninthenumberofantennaused.
DuplexerForseparatingsendingandreceivingsignalsto/fromantenna.Doessendingandreceivingsignalsthroughthesameantennaports(cablestoantenna).
AntennaThisisthestructurethattheBTSliesunderneath;itcanbeinstalledasitisordisguisedinsomeway(Concealedcellsites).
AlarmextensionsystemCollectsworkingstatusalarmsofvariousunitsintheBTSandextendsthemtooperationsandmaintenance(O&M)monitoringstations.
ControlfunctionControlsandmanagesthevariousunitsofBTS,includinganysoftware.On-the-spotconfigurations,statuschanges,softwareupgrades,etc.aredonethroughthecontrolfunction.
Basebandreceiverunit(BBxx)Frequencyhopping,signalDSP,.
18. ANTENNA COUPLING LEVEL (ANC)
It is the stage between antenna & TRX.
A single module called ANC performs function up to 4 RTXs.
For higher capacity a COMBINER stage can be added.
19. TRANS RECEIVER LEVEL (TRX)
Trans-receiverequipment.
Usedforreception&transmissionofRFsignal.
TheAbsoluteRadiofrequencychannelnumber(ARFCN)isallottedtooneTRX&eachARFCNisdividedin8timeslots,henceoneTRXcanprovideconnectionto8subscribersatatime.
OneBTS=12TRX=12ARFCN=12*8=96Users
Soatatimeonly96userscanmakecalls.
20. BASE STATION CONTROL FUNCTION LEVEL (BSF)
This station is ensured by station Unit Module (SUMA): central unit of BTS.
Only one SUMA for one BTS.
Generally clocks for all other BTS module for synchronization purposes. Ex: Abis link…
SUMA
BSF
30. MULTI-INPUT MULTI-OUTPUT (MIMO) ANTENNAS
Mobile MIMO antenna
Directional Base station MIMO antenna
Dual band Wi-Fi MIMO antenna
Single band Omni directional MIMO antenna 2.4-5 GHz
31. LONG TERM EVOLUTION (LTE)
LongTermEvolution(LTE)istheworld'sleading4Gcellularnetworktechnology.
LTE'shighdataratesandlowlatencyenableapplicationssuchasstreamingHDvideo,highdefinitionVoiceoverLTE(VoLTE), broadcasting,andpublicsafetyemergencyresponse.
Bandwidthsrangingfrom1.4MHzto20MHz.
ThismakesLTEanaturalupgradepathforcarrierswithbothGSM/UMTSandCDMA2000networks.
Bandscurrentlyinuserangefrom450MHzto2700MHz,withbandsashighas3.5GHz.
LTEMIMOantennasmustbecarefullydesignedinordertogetthefullbenefitofMIMOtechnology.