Details about cell tower, BTS & Antennas for wireless communication.

1. TOWER TECHNICIAN
Presented By:
Mr. NIMAY CHANDRA GIRI
girinimay1@gmail.com

2. CONTENTE
Objective
Introduction
GSM System & Architecture
Network identities
MS & BTS
Architecture of BTS with configuration
Antenna types & configurations
Different pole types antennas
Tilt

3. OBJECTIVE
TounderstanddetailsaboutBTSsysteminGSMsystem.DifferenttypesofAntennasusedinthemarket.FunctionalstructureofBTS&differentpartsofit.
MIMO&LTEAntennasused.

4. INTRODUCTION
Acellsiteorcelltowerisacellulartelephonesitewhereantennaeandelectroniccommunicationsequipmentareplaced,usuallyonaradiomast,towerorotherhighplace,tocreateacell(oradjacentcells)inacellularnetwork.
Frequencyreuse–samefrequencyin
manycellsites
Cellularexpansion–easytoaddnewcells
Handover–movingbetweencells
Roaming-betweennetworks

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).

7. COMPARED TO FIXED NETWORK

8. GSM ARCHITECTURE
Transcoderisadevicethattakes13KBPSspeechdataandmultiplexesfourofthemintostandard64Kbpsdata.

9. NETWORK IDENTITIES
IMEI(InternationalMobileEquipmentIdentity)
MSISDN(MobileStationISDNNumber)
IMSI(InternationalmobilesubscriberIdentity)
TMSI(TemporaryMobilesubscriberIdentity)
MSRN(MobileStationRoamingNumber)

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

15. BTS FUNCTION ARCHITECTURE

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

21. RF& BTSSTRUCTURE

22. BTS CONFIGURATION

23. CONT…

24. TYPES OF TOWER USED
–Self Supporting
–Monopoles
–Guys

25. TOWER SITE CONFIGURATION

26. ANTENNAS USED
AnAntennaisadevicetotransmitand/orreceiveelectromagneticwaves.Electromagneticwavesareoftenreferredtoasradiowaves.

27. ANTENNAS TYPES USED
PrimaryAntennatypesinWirelessconfigurationsare:
OmniDirectional
Broadcastsinalldirections
Examplesarewhip,helicalanddipole
Directional
Broadcastinasingledirection
ExamplesareYagi,andparabolic
LeakyCoax
Broadcastsalongpathofthecoaxialcable
Coaxialcablewiththecloselyspacedslotsintheouterconductorallowingsignalstopenetratetothecore
Leaky Coax

28. ELECTRICAL & MECHANICAL TILT
Thetiltrepresentstheinclinationorangleoftheantennatoitsaxis.
ElectricaltiltisusedforincreasingordecreasingofBeamradiation.
(+)=>Tx&(-)=>Rx

29. MECHANICAL TILT
Mechanical tilt is adjusted for maximum or minimum coverage area radiation.

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.