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Cell tower, BTS & antennas

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

Publicado en: Ingeniería

Cell tower, BTS & antennas

  1. 1. TOWER TECHNICIAN Presented By: Mr. NIMAY CHANDRA GIRI girinimay1@gmail.com
  2. 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. 3. OBJECTIVE TounderstanddetailsaboutBTSsysteminGSMsystem.DifferenttypesofAntennasusedinthemarket.FunctionalstructureofBTS&differentpartsofit. MIMO&LTEAntennasused.
  4. 4. INTRODUCTION Acellsiteorcelltowerisacellulartelephonesitewhereantennaeandelectroniccommunicationsequipmentareplaced,usuallyonaradiomast,towerorotherhighplace,tocreateacell(oradjacentcells)inacellularnetwork. Frequencyreuse–samefrequencyin manycellsites Cellularexpansion–easytoaddnewcells Handover–movingbetweencells Roaming-betweennetworks
  5. 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. 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. 7. COMPARED TO FIXED NETWORK
  8. 8. GSM ARCHITECTURE Transcoderisadevicethattakes13KBPSspeechdataandmultiplexesfourofthemintostandard64Kbpsdata.
  9. 9. NETWORK IDENTITIES IMEI(InternationalMobileEquipmentIdentity) MSISDN(MobileStationISDNNumber) IMSI(InternationalmobilesubscriberIdentity) TMSI(TemporaryMobilesubscriberIdentity) MSRN(MobileStationRoamingNumber)
  10. 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. 11. THE BASE STATION SUBSYSTEM (BSS) TheBSSconnectstheMobileStationandtheNSS.Itisinchargeofthetransmissionandreception.TheBSScanbedividedintotwoparts: TheBaseTransceiverStation(BTS)orBaseStation. TheBTScorrespondstothetransceiversandantennasusedineachcellofthenetwork.ABTSisusuallyplacedinthecenterofacell.Itstransmittingpowerdefinesthesizeofacell.EachBTShasbetweenoneandsixteentransceiversdependingonthedensityofusersinthecell. TheBaseStationController(BSC). TheBSCcontrolsagroupofBTSandmanagestheirradioresources(upto100BTSs).ABSCisprincipallyinchargeofhandovers,frequencyhopping,exchangefunctionsandcontroloftheradiofrequencypowerlevelsoftheBTSs.
  12. 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. 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. 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. 15. BTS FUNCTION ARCHITECTURE
  16. 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. 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. 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. 19. TRANS RECEIVER LEVEL (TRX) Trans-receiverequipment. Usedforreception&transmissionofRFsignal. TheAbsoluteRadiofrequencychannelnumber(ARFCN)isallottedtooneTRX&eachARFCNisdividedin8timeslots,henceoneTRXcanprovideconnectionto8subscribersatatime. OneBTS=12TRX=12ARFCN=12*8=96Users Soatatimeonly96userscanmakecalls.
  20. 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. 21. RF& BTSSTRUCTURE
  22. 22. BTS CONFIGURATION
  23. 23. CONT…
  24. 24. TYPES OF TOWER USED –Self Supporting –Monopoles –Guys
  25. 25. TOWER SITE CONFIGURATION
  26. 26. ANTENNAS USED AnAntennaisadevicetotransmitand/orreceiveelectromagneticwaves.Electromagneticwavesareoftenreferredtoasradiowaves.
  27. 27. ANTENNAS TYPES USED PrimaryAntennatypesinWirelessconfigurationsare: OmniDirectional Broadcastsinalldirections Examplesarewhip,helicalanddipole Directional Broadcastinasingledirection ExamplesareYagi,andparabolic LeakyCoax Broadcastsalongpathofthecoaxialcable Coaxialcablewiththecloselyspacedslotsintheouterconductorallowingsignalstopenetratetothecore Leaky Coax
  28. 28. ELECTRICAL & MECHANICAL TILT Thetiltrepresentstheinclinationorangleoftheantennatoitsaxis. ElectricaltiltisusedforincreasingordecreasingofBeamradiation. (+)=>Tx&(-)=>Rx
  29. 29. MECHANICAL TILT Mechanical tilt is adjusted for maximum or minimum coverage area radiation.
  30. 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. 31. LONG TERM EVOLUTION (LTE) LongTermEvolution(LTE)istheworld'sleading4Gcellularnetworktechnology. LTE'shighdataratesandlowlatencyenableapplicationssuchasstreamingHDvideo,highdefinitionVoiceoverLTE(VoLTE), broadcasting,andpublicsafetyemergencyresponse. Bandwidthsrangingfrom1.4MHzto20MHz. ThismakesLTEanaturalupgradepathforcarrierswithbothGSM/UMTSandCDMA2000networks. Bandscurrentlyinuserangefrom450MHzto2700MHz,withbandsashighas3.5GHz. LTEMIMOantennasmustbecarefullydesignedinordertogetthefullbenefitofMIMOtechnology.

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