The document discusses tower technician responsibilities, including summarizing: 1) The roles of tower technicians include maintaining cellular tower equipment such as antennas, transmitters, and cables that allow cell phones to connect to networks. 2) Cellular towers use various antenna types and configurations depending on network needs, including directional antennas to focus signals in certain areas and MIMO antennas to increase data capacity. 3) Technicians must understand how cellular network equipment like the base transceiver station (BTS) and antennas function and be able to configure them properly to optimize network performance.

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.