tata final project

8/6/2019 Tata Final Project

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ACKNOWLEDGEMENT

We would like to express our heartfelt gratitude to TATA TELESERVICES LIMITED for

equipping us with the platform to enhance our skills in the field of Mobile communication.

The entire team proved to be very accommodating and cooperative to us without whom

the project would not have been accomplished

We would like to thank Mr. ASHIS CHAWALA , our project mentor, Continental Institute of

Technology, PTU University for giving us invaluable guidelines and moral support She

,Being very enthusiastic and genial, gave us orientation and motivation to gain more

hand-on experience and hence get an edge over.

We would also like to thank all our colleagues in Tata Teleservices Ltd. Who provided us

there priceless time and companionship during the entire training period.

Last but not the least; we are most thankful to our institute Continental institute of eng.

And technology for providing us this opportunity and platform to explore our horizon in the

practical field and gain professionalism and etiquettes along with technical abilities in the

corporate culture.

Continental Institute of Eng. And Technology


2/44

INDEX

1. INTRODUCTION OF TATA TELESERVICE LTD.

2. INTRODUCTION OF CDMA SERVICE.

3. BASIC STRUCTURE OF CDMA NETWORK.

4. MOTAROLA BTS STRUCTURE.

5. PATCHING OF E1 ON DDF BLOCK.

6. DRIVE TEST.

Continental Institute of Eng. And Tec

nology

TATA TELE SERVICES


3/44

C M Y F :

Communications is the

ata roups largest investment and the roups objective is

to provide end-to-end telecommunications solutions for business and residential

customers across the nation, and internationally

he roups communications

activities are currently spread primarily over four companies

ata

eleservices

imited (

) and its associate

ata

eleservices (Maharashtra)imited (

M),

ata

Communication (erstwhile

) and

ata

ky

ogether, these companies cover thefull range of communications services, including:

y Telephonyervices: Fixed and Mobile

y Media and ntertainment ervices: atellite TVy Data ervices: eased ines, Managed Data ! etworks, " # /M # VPN, Dial-up

" nternet, $ i-Fi and % roadband

y Value- & dded ' ervices: Mobile and ( roadband Content/ & pplications, CallingCards, Net Telephony and Managed ' ervices

y Infrastructure ) ervices: ) ubmarine Cable 0 andwidth, Terrestrial Fiber Networkand ) atellite 1 arth ) tations and VSAT Connectivity


PROF :-

Tata Teleservices is part of the INR Rs. 2, 51,543 crore Tata group that has over 8o

companies, over 3, 30,000 employees and more than 3.2 million shareholders. With acommitted investment of INR36, 000 crore in telecom, the group has a formidable presence

across the telecom value chain.

Tata Teleservices spearheads the groups presence in the telecom sector. Incorporated in

1996, Tata teleservices was the first to launch CDM mobile services in India with theAndhra Pradesh circle.

Beginning with its acquisition of Hughes Telecom(India) Limited in December 2002[now

renamed Tata teleservices (Maharashtra) Limited ],which provide services in the Mumbai


4/44

and rest of Maharashtra telecom circle, the company has swung into expansion mode and

currently has a pan-India state of the art network.


INTRODUCTION OF CDMA

CDMA/WIRELESS COMMUNICATION

MULTIPLE ACCESS

Why there is requirement of multiple access schemes? The answer is that the

internationalauthority for frequencymanagementhasallocated25MHzbandto the

cellular telephony2

As we know that today there are many cellular users and to

provide service to allof thema large frequencyband is required 2 But theband is

limited to 25MHz 2 So different multiple access schemes are used 2 It means that


5/44

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8/44

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10/44

ALL OF THESPREAD-SPECTRUM SYSTEMS HAVE TO SATISFY TWO CRITERIA:

Thebandwidthofthetransmittedsignalmustbegreaterthenthetransmitted

Signal

Transmitted bandwidth must be determined by some function that is

independentofthemessageandisknowntothereceiver

Bandwidthexpansioninspreadspectrumsystemsisachievedbyusingafunctionthatisindependentofthemessage,thus itismoresusceptibletowhitenoiseasopposed

to other communication techniques, such as FM and PCM Spread spectrum

techniqueshaveotherapplicationsthatmakeituniqueanduseful

THESE APPLICATIONS INCLUDE:

1 Anti-jamcapability-particularly fornarrow-bandjamming

2 Interferencerejection

3 Multiple-accesscapability

4Multi-pathprotection

5Convertoperationsorlowprobabilityofintercept(

PI)

6 Securecommunications

7 Improvedspectralefficiency-inspecialcircumstances

8 Ranging

CDMA is a wireless communications technology that uses the principle of spread

spectrum communication The intent of CDMA technology is to provide incr eased

bandwidth in a limited frequency system, but has also other advantages including

extendedrangeandmoresecurecommunicationsInaCDMA system,anarrowband

message signal is multiplied by a spreading signal, which is a pseudo -noise code

sequencethathasaratemuchgreaterthanthedatarateofthemessage CDMA uses

thesecodesequencesasameansofdistinguishingbetweenindividualconversations

All users in the CDMA system use the same carrier frequency and may transmit

simultaneously InthisdocumentIwillbediscussingaboutCDMA indetail

CDMA isadrivingtechnologybehindtherapidlyadvancingpersonalcommunications

industry Because of its greater bandwidth, efficiency, and multiple access

capabilities, CDMA is becoming a leading technology for relieving the spectrum

congestion caused by the explosion in popularity of cellular mobile phones, fixed

wirelesstelephones,andwirelessdataterminalsSincebecominganofficially



11/44

recognizeddigitalcellularprotocol,CDMA isbeingrapidlyimplementedinthewireless

communicationsnetworksofmany largecommunicationscorporations CDMA stands

for "CodeDivision Multiple Access " It is a form of spread -spectrum, an advanced

digitalwirelesstransmissiontechniqueInsteadofusingfrequenciesortimeslots,as

do traditional technologies, it uses mathematical codes to transmit and distinguish

between multiple wireless conversations Its bandwidth is much wider than that

required forsimplepoint-to-pointcommunicationsat thesamedata ratebecause it

uses noise-like carrier waves to spread the information contained in a signal ofinterestoveramuchgreaterbandwidth

However,because theconversationstaking

placearedistinguishedbydigitalcodes,manyuserscanshare thesamebandwidth

simultaneously The advanced methods used in commercial CDMA technology

improvecapacity,coverageandvoicequality,leadingtoanewgenerationofwireless

networks

ld-fashioned radio receivers separate stations and channels by filtering in the

frequencydomain CDMA receivers,conversely,separatecommunicationchannelsbya pseudo-random modulation that is applied and removed in the digital domain

Multiple users can therefore occupy the same frequency band This universal

frequencyreuseiscrucialtoCDMA'sdistinguishinghighspectralefficiency

CDMA hasgained international acceptance by cellular radio system operators as an upgrade

becauseofitsuniversalfrequency reuseandnoise-likecharacteristics CDMA systems

provide operators and subscribers with significant advantages over analog and

conventional TDMA-basedsystems

THE 850MHZ CDMA BAND IS MOST POPULARLY USED ALL OVER THE WORLD.

THIS BAND AS MENTIONED IN THE PREVIOUSSLIDE WORKS BETWEEN

824-849MHz Usedforthe Reverselinkcommunication

869-894MHz UsedfortheForwardlinkcommunication

TheCDMA bandisdividedintosubbandsasshownabove The Total Bandof25MHz

isdivided intosmallchannelsof30 Hz each AnactualCDMA carrierwillbeusinga

multiple of the 30Hz channels

That means for an actually utilized bandwidth of

1 23MHzwewillneed41X30 Hzchannels

THE FOLLOWING EQUATION GIVES THE RELATIONSHIP BETWEEN THE

CHANNEL NUMBERS AND THE ACTUAL FREQUENCY.

Reverse LinkFrequency = (825 + N0 03)MHz

Forward LinkFrequency = (870 + N0 03)MHz

Where N = CDMA channelnumber

CDMA SPREAD SPECTRUM TERMINOLOGY


12/44

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13/44

From a system viewpoint, the performance increase for very wideband systems is

referredtoas "processgain". Thistermisusedtodescribethereceivedsignalfidelity

gainedatthecostofbandwidth. Errorsintroducedbyanoisychannelcanbereduced

toanydesired levelwithoutsacrificing the rateof information transferusingClaude

Shannon'sequationdescribingchannelcapacity:

C=W log 2 (1+S/N )

Where,

C = Channelcapacityinbitspersecond,

W = Bandwidth,

S/N = Energyperbit/Noisepower.

Thebenefitsofincreasingbandwidthbecomeclearer. The S/N ratiomaybedecreased

withoutdecreasingthebiterrorrate. Thismeansthatthesignalmaybespreadover

a largebandwidth with smaller spectralpower levelsand stillachieve the requireddata rate. If the total signal power is interpreted as the area under the spectral

densitycurve,thensignalswithequivalenttotalpowermayhaveeitheralargesignal

powerconcentratedinasmallbandwidthorasmallsignalpowerspreadoveralarge

bandwidth.

Spread Spectrum

CDMA isa spreadspectrummodulationscheme. This implies that the transmission

bandwidthismuchlargerthantheinformationbandwidth.

Direct Sequence Spread Spectrum

Indirectsequencemodulationthecarrierfrequencyisfixedandthebandwidthof thetransmitted signal is larger and independent of the bandwidth of the information

signal. Some properties of direct sequence spread spectrum systems are listed in

table.


14/44

CDMA Codes

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15/44

the c e eneration singtheregister shownin Figure. Letinitial stateis [1 0 1] or

register. Theoutputofstage 3 is theoutputoftheregister.

After clocingthe

its throughtheregister:

TYPE

OF PNCODE

1.PN LONG CODE2.PN SHORT CODE

PNLongCode

TheLongCodeis a PN sequencethatis 242 - 1 bits(chips) long. Itis generatedatarateof 1.2288 M

ps (or Mcps) giving itaperiod (time

eforethe sequencerepeats)


16/44

ofapproximately41.4 days. Thelongcodeisusedtoencryptuserinformation. Both

thebasestationand themobileunithaveknowledgeof thissequenceatanygiven

instantintimebasedonaspecifiedprivate longcodemaskthatisexchanged.

LongCodeMaskgovernsthegenerationofa LongCode. A longcodemaskisa42-bit

codewhichdefine the initialvaluesusedby the longcodegenerator. Knowledgeof

thislongcodemaskallowsthebasestationormobileusertogeneratethesame PN

LongCode. Generatingthesamelongcode(synchronized intime)atbothendofthelinkallowsinformationtobeencryptedanddecrypted.

A uniqueandprivate,longcodemask(thus, PN longcode)isassignedtoeachCDMA

user. Thiscodeisreferredtoasa usermask . Theusermaskisexchangedbetween

the mobile and the serving cell(s)/sector(s), which allows user traffic data to be

encryptedonboththeforwardandreverse links. A different longcodemask isused

to generate the long code for encryption and decryption of Access and Paging

information moreonthislater.

PN Short Codes

TheShort Code is a PN sequence that is 215 bits (chips) in length. This code is

generatedat1.2288Mbps(orMcps)givingaperiodof26.67 ms. thiscode isused

forfinalspreadingofthesignalandistransmittedasareferenceknownasthe Pilot

Sequence by the base station. All base stations use the same short code. Base

stations are differentiated from one another by transmitting the PN short code at

different offsets inabsolute. This time offset isknownasa PN Offset. Allbase

stationsandmobileshaveknowledgeofthiscode,however,mobileunitsdonothave

initial knowledge of absolute time. Mobile units initially search (in time) until they

synchronizewithapilotcode transmittedbyabasestation. Thebase station then

conveystiminginformationtothemobile moreonthisstufflater.

Walsh Codes

CDMA defines a group of 64 orthogonal sequences, each 64 bits long, known asWalsh Codes. ThesesequencesarealsoreferredtoasWashFunctions. Thesecodes

aregeneratedat1.2288Mbps (Mcps)giving themaperiodofapproximately52 s.

Theseareusedto identifyusersontheforwardlink. Forthisreasontheyareloosely

referredtoasCDMA channels. Allbasestationsandmobileusershaveknowledgeof

allWalshcodes.

Orthogonal functionshavezerocorrelation. Twobinarysequencesa reorthogonal if

theprocessofXORingthemresultsinanequalnumberof1sand0s.

Example:0000

(XOR) 0101

------


17/44

0101

Generation Sequen

e:

- Seed

- Repeatright &!elow

- Invert: diagonally

CDMAChannels

Justwhenonegrasps anunderstandingofthe CDMA carrier,whichis 1.25 MH" wide,

someone talks about "traffic channels" and confuses the issue. The fact is thatwith

CDMA, the path by which voice or data passes is the entire carrier. CDMA trafficchannels aredifferent: theyaredependentontheequipmentplatform onwhichtheCDMA is implemented. Mostly channels aredesignatedinthreeways:

Effe # tivetraffi # channels

Thenumberof "Effective" traffic channels includes the traffic carrying channels lessthe softhandoff channels. The capacityofaneffectivetraffic channelis equivalentto

thetraffic carrying capacityofananalogtraffic channel.

Actualtraffic channels

Thenumberof "Actual" traffic channels includes theeffective traffic channels,plus

channels allocatedfor softhandoff.

Physicaltraffic channels

The number of "Physical" traffic channels includes the Pilot channels, the Syncchannels,the Paging channels,the Soft HandoffOverhead channels andthe Effective

(voiceanddata) traffic channels.

CDMA uses the terms "forward" and "reverse" channels$

ust like theyareused inanalog systems. Basetransmitequates tothe forwarddirection,andbasereceive isthereversedirection. ("Forward" is whatthe subscriberhears and "reverse" is what

the subscriber speaks.)


18/44

CDMA FOR%

ARDCHANNELS

PilotChannel

Thepilot channel is usedby the mobileunit toobtain initial system synchronization

andtoprovidetime,frequency,andphasetrackingofsignals from the cell site.

Sync Channel

This channel provides cell site identification, pilot transmitpower,and the cell sitepilotpseudo-random (PN) phaseoffset information. Withthis informationthe mobileunits canestablishthe System Timeas wellas thepropertransmitpowerleveltouse

toinitiatea call.

PagingChannel


19/44

Themobileunitwillbeginmonitoringthepagingchannelafterithassetitstimingto

the System Timeprovidedby thesyncchannel. Onceamobileunithasbeenpaged

andacknowledges thatpage,callsetupand trafficchannelassignment information is

thenpassedonthischanneltothemobileunit.

Forward Traffic Channel

This channel carries the actual phone call and carries the voice and mobile power

controlinformationfromthebasestationtothemobileunit.

CDMA REVERSE CHANNELS

Access Channel

When themobileunit isnotactiveona trafficchannel, itwillcommunicate to the

base station over the access channel. This communication includes registration

requests, responses to pages, and call origination. The access channels are pair ed

withacorrespondingpagingchannel.

Reverse Traffic Channel

Thischannelcarriestheotherhalfoftheactualphonecallandcarriesthevoiceand

mobilepowercontrolinformationfromthemobileunittothebasestation.

ADVANTAGES OF CDMA

CDMA technologyhasnumerousadvantagesincluding:

y Coveragey Capacityy Clarityy Costy Compatibilityy Customersatisfaction

o Coverage

CDMA's features result in coverage that isbetween 1.7and3 times that of

TDMA:

y Powercontrolhelpsthenetworkdynamicallyexpandthecoveragearea.


20/44

y Codingand interleavingprovide theability tocovera largerarea for thesameamountofavailablepowerusedinothersystems.

o Capacity

CDMA capacity is ten to twenty times thatofanalogsystems,and it'sup to

fourtimesthatofTDMA. Reasonsforthisinclude:

y CDMA'suniversalfrequencyreusey CDMA usersareseparatedbycodes,notfrequencies. y Powercontrolminimizes interference, resulting inmaximizedcapacity.CDMA's

soft handoff also helps increase capacity. This is because a soft handoff


21/44

requires less power.

oClarity

Often CDMA systems canachieve wireline claritybecauseof CDMAs strong

digitalprocessing. Specifically:

y Therakereceiverreduces errorsy Thevariableratevocoderreduces theamountofdatatransmittedperperson,

reducinginterference.


22/44

y Thesofthandoffalsoreducespowerrequirementsandinterference.y Powercontrolreduceserrorsbykeepingpoweratanoptimallevel.y CDMAswidebandsignalreducesfading.y Encodingandinterleavingreduceerrorsthatresultfromfading.

o Cost

CDMAsbettercoverageandcapacityresultincostbenefits:

y Increased coverage per BTS means fewerareneeded to cover agivenarea.Thisreducesinfrastructurecostsfortheproviders.

y Increasedcapacityincreasestheserviceprovidersrevenuepotential.

CDMA costspersubscriberhavesteadilydeclinedsince1995forbothcellularand PCS

applications.

o Compatibility

CDMA phonesareusuallydualmode. ThismeanstheycanworkinbothCDMA

systemsandanalogcellularsystems.

Some CDMA phonesaredual bandaswellasdual mode. They can work in

CDMA modeinthe PCS band,CDMA modeinthecellularband,oranalogmode

in an analog cellular network.

o Customer satisfaction

CDMA resultsingreatercustomersatisfactionbecauseCDMA providesbetter:

y Voicequalityy Longerbatterylifeduetoreducedpowerrequirementsy Nocross-talkbecauseofCDMA'suniquecodingy Privacy--again,becauseofcoding.

y TABLE 11:CDMA-GSM PARAMETERS


23/44

PARAMETERS CDMA GSM

Uplink Frequencies 824-849MHz(US Cellular)

1850-1910MHz(US PCS)

890-915MHz(Europe)


Downlink Frequencies 869-894MHz(US Cellular)


935-960MHz(Europe)

1930-1990MHz(US PCS)Multiple Access Tech. CDMA TDMA

Carrier Separation 1.25MHz 200 KHz

Channel Data Rate 1.2288Mchips/sec 260.833 Kbps

Frequency Planning Notrequired Required

Mobile Handset Power 23mWmax 2Wmax

Handoff Soft/Softer Hard

y CDMA HANDOFFy Theactof transferringsupportofamobilefromonebasestationtoanother is

termedhandoff. Handoffoccurswhenacallhastobehandedofffromonecell

toanotheras theusermovesbetweencells. A CDMA cellularnetworkhandles

mobileunitcallprocessing transitionsmoresubtlythantheother technologiesusedformobilecommunicationsnetworks.

y CDMA HandoffsrequirethatthemobileunitmaintainanongoinglistofpossiblebasestationsitesthatitmayuseforHandoffsasittravelsthroughthesystem.

CDMA offerstheuniquefeatureofallowingmobileuserstoprocesssignalsfrommultiple (up to 3)base stations simultaneously. The terminologyandvarious

typesof

y HandoffsassociatedwithCDMA aredescribedbelow.y Types ofHandoffs

TherearebasicallytwotypesofHandoffmechanism.

y HardHandoffy SoftHandoff


24/44

o HardHandoffInatraditional "hard" handoff,the connectiontothe current cellis broken,andthenthe connection to thenew cell is made. This is knownas a "brea

&-before-ma

&e"

handoff. Sinceall cells in CDMA use the same frequency, it is possible to make the

connectiontothenew cellbeforeleavingthe current cell. This is knownas a "ma & e-before-brea & " or "soft" handoff. Soft handoffs require less power,which reduces

interferenceandincreases capacity.

y SoftHandoffThe conditionwheretwo cells are in simultaneous communicationwiththe mobile iscalled Soft Handoff. Soft Handoffwill continueuntil thepilot signal from oneof thecontributing cells drops belowa predefined threshold (TDROP). As the mobile moves

from its current cell (source cell) to the next cell (target cell), a traffic channel


25/44

connection is simultaneously maintained with both cells. Figure (a) and Figure (b)

illustratethesimultaneous linksduringsofthandoff. On the forward link(seeFigure

(a)),themobileusestherakereceivertodemodulatetwoseparatesignalsfromtwo

differentbasestations. The twosignalsarecombined toyieldacompositesignalof

betterquality. On the reverse link (see Figure (b)), the mobiles transmit signal is

receivedbybothbasestations. The twocellsdemodulate thesignalseparatelyand

send thedemodulated framesback to theMobile SwitchingCenter(MSC). TheMSCcontainsaselectorthatselectsthebestframeoutofthetwothataresentback.

On Forward Link, when the Soft Handoff is initiated, the two base stations begin

transmitting data to the mobile. The mobile receives information from the twoforwardlinksandusesthe RAKE receivertocoherentlycombine thesignalsusingthe

pilotsequence transmittedbyeachcell/sectoras its reference. Thiscombinationof

multipleforwardlinksignalsimprovesoveralllinkperformance.

Advantages ofCDMA Handoff

1. Itis "soft",meaningthatcommunicationisnot interruptedbythehandoff. This is

sometimescalled "makebeforebreak." Thismeansfewerdroppedcallsforusersandhighercustomersatisfactionforoperators.

2. Thehandoffisnotabrupt,butratheritisaprolongedcallstateduringwhichthere

is communication via two or more base stations. The multi-way communication

diversity improves the link performance during the handoff. The diversity gain

partiallycompensatesforthelargepathlossatthecellboundary.

3. The signal measurement that triggers the handoff is performed by the mobile

stations,notthebasestations.

Need OfCDMA

Designers and planners of the communication systems are often concerned

with the efficiency with which the systems utilize the signal energy and

bandwidth. In most communication systems these are the most important

issues. In some cases, it is necessary for the system to resist external

interference, to operate at low spectral energy, to provide multiple access

capability without external control and secure channel not accessible to the

outsiders. Thus,itissometimesunavoidabletosacrificesomeoftheefficiency

in order to enhance these features. Spread spectrum techniques allow

accomplishingsuchobjectives.


26/44

The theoretical aspects of using spread spectrum in a strong interferenceenvironment have been known for over forty years. It is only recently that

practicalimplementations becamefeasible.


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Inthebeginning,thespreadspectrumtechnologywasdevelopedandusedfor

military purposes and their implementations were too expensive for the

commercialapplications. New technologicaladvancementssuchas VLSI,and

advanced signal processing techniques made it possible to develop less

expensive spread spectrum equipment for civilian use. Applications of this

technology include cellular, wireless data transmission and satellite

communications.

Definition ofCDMA

CDMA is a wireless communications technology that uses the principle of

spreadspectrumcommunication. The intentofCDMA technologyistoprovide

increased bandwidth in a limited frequency system, but has also other

advantages includingextended rangeandmoresecurecommunications. Ina

CDMA system, a narrowband message signal is multiplied by a spreading

signal,which isapseudo-noisecodesequence thathasa ratemuchgreater

than the data rate of the message. CDMA uses these code sequences as a

means of distinguishing between individual conversations. All users in theCDMA system use the same carrier frequency and may transmit

simultaneously.

CDMA stands for "Code Division Multiple Access." It is a form of spread-

spectrum, an advanced digital wireless transmission technique. Instead of

using frequencies or time slots, as do traditional t echnologies, it uses

mathematical codes to transmit and distinguish between multiple wireless

conversations. Its bandwidth is much wider than that required for simple

point-to-pointcommunicationsatthesamedataratebecauseitusesnoise -like

carrierwavestospreadtheinformationcontainedinasignalofinterestovera

muchgreaterbandwidth. However,becausetheconversationstakingplacearedistinguished by digital codes, many users can share the same bandwidth

simultaneously.

The advanced methods used in commercial CDMA technology improve

capacity,coverageandvoicequality, leading toanewgenerationofwireless

networks.

The850MHzCDMA band ismostpopularlyusedallover theworld. Thisband

asmentionedinthepreviousslideworksbetween,

y 824-849MHz Usedforthe Reverselinkcommunication. y 869-894MHz UsedfortheForwardlinkcommunication.

The Following equation gives the relationship between the channel numbers

andtheactualfrequency.

Forward LinkFrequency = (870 + N0.03)MHz

Reverse LinkFrequency = (825 + N0.03)MHz


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Where N = CDMA channel number

BASIC STRUCTURE OF CDMA NETWORK

Thebasicstructureofthenetworkisshowsinthefigure1.

Thecomponentsaredescribebelow:

1)Microwave Antenna

2) ODU

3)IDU

4)MUX

5)DDF

6) BTS

7) Sectorantenna

8) GPS antenna

1) Microwave Antenna:

MWantenna isusedtotransmitMWsignal inair.thisantennaisdirectionalantenna.

Itmeansitwilltransmitinonedirectiononly. Thisisusedtoconnect E1linkbetween

two sites.Two MW antennas are there in each site to establish a ring network..Itsendstrafficto BSC.Thetransmittingfrequency isintermsofGHz.Parabolictypesof

antennaareusedin TTSL.

2) ODU:

ODU stands for out door unit. ODU is attached to the MWantenna. Its function is

modulatesthe incomingsignal fromIDU withhighercarrier frequencysignal. Means

frequencyupconvertionisperformedhere.

3) IDU:

IDU stands for indoorunit.Itconvert RFsignal in toopticalsignal.Toestablish ring

networkmorethenoneIDU canberequired.

4) MUX:

HereMUXareusedtocarry E1fromonesitetoanothersite.BTS isconnectedtothe

MUX via DDF. Here MUX can carry both data and voice traffic.MUX uses

SDH(Synchronous Digital Hierarchy)technology.Different types are:


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Typecapacity

a.STM-021E1b.STM-163E1c.STM-44*63E1d.STM-1616*63E1e.STM-6464*63E1f.STM-256256*63E1

Single E1 has a capacity of 2.048 Mbps.MSH11c(STM-1) and MSH41c(STM-4) are

used TTSL.

5) DDF:

DDFstandsforDIGITAL DISTRIBUTION FRAME.DDFisapointwere E1isterminated.

Itprovidesonlyconnectivitybetweentwopoint.

6) BTS:

BTS standsfor BASE STATION TRANSCIEVER SUBSYSTEM.BTS isconnectedwith GPS

antenna via RF cable. The CDMA signal is processed by BTS.BTS include filter,

amplifier and other control module. BTS receive and transmit signal via sector

antenna.

7) Sector antenna:

Sector antenna communicate with mobile.360 Degree is divided in to three parts

Alpha Beta and Gamma. Also known as intra, metro and ultra. All three partsare

separatedby maximum up to 120degree. Herebecauseof sector the coverage is

increase .Sectorantennaisadirectionalantenna.

8) GPS system:

A GPS standsfor Globlepositioningsystem. A GPS receiverislocatedinthe BTS and

isconnectedtoantennavia RFcable.Thisprovidessynchronizationsignalandtiming

signal toCDMA network forchannelcoding.Thisantennacommunicatewithsatellite

continuously.

MOTOROLA BTSSTRUCTURE

2.1 ListofBTS Cards


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1.BBX(BROAD BAND TRANSCEIVER)2.MCC-24/MCC-8E (MULTICHANNEL CDMA)3.GLI(GROUP LINE INTERFACE)4.CIO (COMBINER INPUT/OUTPUT)5.GPS (GLOBAL POSITION SYSTEM)6.CSM(CLOCK SYCHRONIZATION MANAGER)7.HSO (HIGH STABILITY OSCILLATOR)-optional8.LFR (LOWFREQUENCY RECEVIE)-Optional9.C-CCP CDMA CHANNEL PROCESSOR10.LPA SHELF LINEAR POWER AMPLIFIER11.AMR ALARMMONITORING AND REPORTING12.DBPFDUAL BAND PASS FILETR

COMBINER (4:1and2:1)

2.2 OverviewofCardsfunctionality

y BBX:

The BBXprovidesthegenerationofthe Pilotsignal,theconversionfromdigital

base band to RF for the forward link and RF to digital base band for the

reverselink.

Controlled By:- Group LineInterface(GLI)cardviaConcentrationHighway

Interface(CHI)

The BBXreceivesclockandsynchronizationsignalsviatheCCDfromtheCSM.

y MCC-24/MCC-8E (MULTI CHANNEL CDMA)

TheMCCcardcontain thecircuitrynecessaryto implement likesyncchannel,pagingchannel,accesschannelandtrafficchannel. A singleCDMA channelon

anMCCcard isreferredtoasachannelelement.MCC-8E supportsuptoeight

channel element, while MCC-24 supports up to 24 channel elements. Each

channel element contains circuitry to provide the CDMA modulation and

demodulationforasync,paging,accessortrafficchannel. TheMCCcardalso

performsthenecessaryCDMA spreadinganddispreadingfunction.

The interface for the MCC-24 and MCC-8E include the GLI for control and

trafficdataand the BBX2 for the forwardbasebanddata,reversebaseband

and CCD for clocks.

y GLI(GROUP LINE INTERFACE)


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The GLIcard functionas the BTS controllerandprovideroutingof trafficand

control informationand O&MfunctionforallactivedevicesintheC-CCP cage.

It isthecontrolleroftheC-CCP cageandactasmessagerouterbetweenthe

CBSC and the BTS equipment. The GLI2 interfaces to the CBSC via LAPD

control link on a 64/56 kbps timeslot allocated on the digital span line

connectingthecellsitetotheCBSC.Each SC4812T or SC4812ET hastwo GLI2

withonbeing Activeandtheotherinstandbymode. Inactivemode,the GLI2

provides traffic information to theMCCs,control information totheMCCsandBBXs,andcontrolinformationtotheother GLI2viaan Ethernet LAN.

The GLI is2N redundantoneC-CCP cagesupportuptotwo GLI2s.Instandbymode,the GLI2stays insyncwiththeactive GLI2sothat itcanbecomethe

active GLI2ifnecessary.

y CIO (COMBINER INPUT/OUTPUT)

Each C-CCP shelf has one CIO.The CIO is a passive RF interface card thatservesasanextensionofthebackplane.RXsignalsareroutedfromtheMPCor

EMPC then split to several levels to support up to 12 primary and one

redundant BBX(viatheswitchcard).Intheforwardlink,theCIO combineseach

of the 12 primary TX paths with their redundant path(via BBX2 switch

card),then routes the signals to the appropriate LPA cage. There are two

differentversionsoftheCIO board.

1.3sector2.6sector

y GPS (GOBAL POSITION SYSTEM)

A GPS stands for Global Positioning System. A GPS receiver is located in the

BTS and isconnected toantennavia RFcable. Thisprovidessynchronization

signal and timing signal to CDMA network for channel coding. This antenna

communicationwithsatellitecontinuously.

y CSM(CLOCK SYNCHRONIZATION MANAGER)

The CSM maintain CDMA system time and generates the master clock and

reference signals for other CDMA system modules. To provide the required

synchronizationfortheCDMA frames,theCSMcanphaselockuptotwotypes

ofsources,a GPS receiver,or the LFR/HSO. The GPS receiver is theprimary

sourceandthe LFR orHSO istheredundantsource.

y CCD (CDMA CLOCK DISTRIBUTION SUBSYSTEM)


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ThegenerationoftheCDMA clockandsynchronizationsignals isprovidedby

the CSM.The CSM generates the CDMA clock (19.6608 MHz) ,even second

referenceandtheabsolutetimeofdayinformation .TheCDMA clockandsync

isroutedtotheC-CCP viatheCCD.TheCCDbufferstheCDMA clockandsync

and directs these signals out to the MCCs,BBXs,and the GLIs.Each CSM is

linked tooneandonlyoneCCD card. TheCCD card reports internalalarmsbackto itsrespectiveCSM.Incaseof failure,theactiveCSM thenseamlessly

switchestotheredundantCSMandCCDpair.

y HSO (HIGH STABILITY OSCILLATOR) optional

The High Stability Oscillator (HSO) also is an optional card that provides

backup for the GPS.The HSO module is and alternate source of the

synchronization and absolute time information that is required at a CDMA

BTS.Itprovidesapreciseoscillatoras thebackupsource for timingreference

where there is a loss of the GPS signal, A GPS failure, or a Primary CSM

failure. Theoutputof theHSO card is routed to theCSMcards,whichderive

the appropriate time references for the frame. The HSO is guaranteed to

provide GPS timing for24hours,atminimumbutcannotbeused tobringa

siteintoservice.

y LFR (LOW FREQUENCY RECEIVE) optional

The LFR isanoptionalcardthatprovidesbackupforthe GPS.The LFR module

is an alternate source of the synchronization and absolute time information

that is required at a CDMA BTS. The LFR is used to provide a stable time

referencewhen there isa lossof the GPS signal,a GPS failure,oraprimary

CSM failure. Theoutputof the LFR card is routed to theCSM B card,which

derives the appropriate time references for the frame. The LFR requires a

dedicated LFR antenna. The LFR isa LoranCreceiver,whichuses the LoranC

standard. Thisisnottobeemployedinanyofhe TTL BTS.

y C-CCP POWERSUPPLY CONVERTER

TheDCpowersupplyconvertercards installed intheC-CCP shelfconvertthe

input voltage to the necessary DC voltages required to power the various

modulesintheC-CCP shelf. Theprimaryinputvoltageis-48voltsDC.

Powersupplymodulesworkonaloadsharingbasis. Ifonefails,theotherswill

deliver full power to the rest of the modules in the shelves. They are hot

swappable.

y LPA SHELF


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The four linear power amplifiers(LPAs) per three sectors of one carrier are

combinedin softfailredundancy.Insoftfailredundancy,noneofthesectors

gooutofserviceifan LPA modulefails. Intheeventofan ST-LPA failure,the

LPA module takes itselfoutof service sendsanalarm to the GLI2,and the

threesectorssupportedby that LPA moduleoperateat2.5dbreducedpower.

Each trunked LPA set operates independently and is monitored separately.Monitoringandcontrolofthe LPAsisviathe RS485bustothe GLI2.Thegroup

line interface(GLI2)queries the LPAsfor: Alarmstatus, Parameters involvingIntermodulation Distortion (IM) suppression, Electronic ID, and the General

stateofdevice.

y AMR (ALARM MONITORING AND REPORTING)

Therewillbeadifferenttypeofproblemin BTS likeanyofthecardfail,main

supplyfail,rectifiersystemfail, LPA fail. Toindicatethisproblemweusealarm

system. Byusingthiscardthedifferenttypesofalarmaresendingtothe OMC

trough E1 so OMC can take necessary action . This card continuously

monitoringandsendingreportto OMC.Therearetwo AMR cardsareavailable

becauseifoneofthe AMR cardfailthenanotheronecantakeplace.

y DUAL BAND PASS FILTER

The TXdual Bandpasfilterisanoptionthatcanbeemployed iftheframehasoneor twoadjacentornon-adjacentcarriers ina3-sector system. Itallows

thecarriers tooperateanywhere in the transmitbandwithout tuningof the

combiners. The TX DBPF module supports 2 carriers and has the same

dimension as the 2:1 cavity combiner. The DBPF module offers transmit

filteringbutnocombiningof theCDMA signal. Maximumof6per-48volt SC

4812T frame.

y COMBINER (4:1 AND 2:1)

The LPA outputareroutedtoeithera4:1or2:1cavitycombinerthat isused

tocombinefourortwononadjacentCDMA carriersontoasingle TXantenna.A combinercanbeusedonlywhenthecarriersthatneedtobecombinedare

notadjacent (alternate).Odd channels canbecombinedononeantennaand

evenchannelsonanother. Thesecombinersareinstalledinternaltotheframe

withamaximumquantityofsix2:1combinersandthree4:1combinersper-

48volts SC4812T frame.

3.Function ofBTS on the RF link.


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y FORWARD LINK

The CBSC transmits a multiplexed digital data stream containing control

signalsandforwardlinktrafficdataforallsubscriberscommunicatingwiththe

BTS overahigh-speed Telcospan line in T1(1.544Mbps)or E1(2.048Mbps)

format. In circuit data system ,the digital signals are routed from thepunchblock,Channelservice Unit(CSU ),andspan I/oblock to the Group line

interface(GLI)moduleviathedigitalsignalsareroutedfromthepunchblockto

the BTS Router(BTSRTR) .The BTSRTR converts the incomingspansignals to

digital LAN signals and its output are cabled to front of the Group Line

Interface(GLI3)moduleby100Base-T cables.

The GLImodule routes thespeech trafficand requiredcontrol information totheMCCmodulesforprocessing. Trafficdataforeachsubscriberinasector is

formattedandappliedtoachannelelementontheMultiChannelCDMA card.

EachCE encodes the trafficdataand insertspowercontrol information intoa

forward link data stream. The traffic data stream is converted into a CDMA

baseband format, using a unique Walsh code assigned by the cont rol

information for that subscriber. The output from all CEs for a sector are

summed together and routed to the Broadband Transceiver (BBX).The

compositesignal isspreadbytheassignedInterphase(I)and Quadrature(Q)

Pseudo-random Noise (PN) mask codes to reduce I&Q components.A pilotsignalisappliedtoDigital-to-Analog(D/A)converterstoproduceanalogIand

Q basebandsignalsandthenup-convertedto RFonthe BBX.

The low-level RFdrivesignal isapplied to the trunked Linear Power Amplifier

(LPA)Assembly, which amplifies the signal to the level required for

transmission via the site antenna. Three sectors share the resources of a

composite power amplifier assembly consisting of four single carriers feedforwardamplifier, LPA,modules.Thistrunkingtechniquesignificantlyincreases

theefficiencyofthe RFchain.

y REVERSELINK

Reverselinksignalsfromsubscribermobileunitsenterthe BTS throughthe RXpath. Eachofthesectorhastworeceivebranches,mainandDiversity,witha

dedicatedantenna. The receivedsignalat the RXport is routed through the

DRDC (Duplexer, RX filter,Directionalcoupler)/TRDC (TX filter, RX filter,andDirectionalcoupler)totheMulticoupler Preselectorcard(MPC),whichprovideslow-noiseamplification. TwoMPCmodulesareused,onefortheMainbranches

andonefortheDiversitybranches. TheMPCoutputisroutedtothecombiner

Input/Output(CIO)cardthroughtheC-CCP backplan.TheCIO splitsthesignal

androutesittothe BBXbythewayoftheC-CCP backplane. The BBXmodule

for each sector contains two identical receiver strips,oneeach for the Main

and Diversity signals. The main and Diversity signal outputs are amplified,

downconverted,demodulatedanddigitized.


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Patching ofE1 cable on DDF Block.

Introduction

TheaimofcommunicationsystemhasbeentogetmoreandmoreInformation

transmittedonasinglecable. These involvegatheringanumberofsourcestogather, transmitting them to gather and then send separating them and

passingthemtotheindividualreceivers.

E1 was introduced in the 1960s.E1 is the digital communication link that

enablesthetransmissionofvoice,dataandvideosignalsattherateof2.048

Mbps.

Why E1indemands?:

y SimplificationofNetwork:

E1 simplifies the task of Networking different types of communication

equipment.E1linkcarrybothdataandvoiceonasingledigitalcommunication

link.

y QualityofServices:

E1alsoprovidesasignal,whichissuperiorinquality,thentheanaloguesignalprovides. In analogue signal, noise and distortion is also amplified so it

degrades the quality of signal. While in E1 system because of signal

regenerationwegotexactsignalatthereceiverside.

Process ofE1 Patching

Tools: Krone Tools,Wirecutter, LED, Loop Tester,DDF Block

Procedure:

y Pass E1Cable Under Groundin Switch RoomfromDDFtoMUX.y OpentheInsulationofCableCat5.y Locate the Proper E1slotonDDF Block. In TATA eachDDFblockcontain4 E1

slotin One Row. DDFblockhas12rows.

y MounttheCableendin E1slotonDDFand Punchusing Kronetool.y Use PropersideofKrone Tool & Tip.


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y

E1 patching

TestingofE1

There are mainly two methods to check E1.

1.Using LED: Put external LED in E1 slot on DDF block. Note down that Itsglowornot. Ifits glowthenits E1 connectionis correct.


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2. Using Loop Cable: Put Loop cable in Txand Rx slotof E1 and check ByComputerin O&M Room.


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DriveTesto In ' ( odu ) ' 0 on

A basic objectiveof CDMA RF performanceengineering is todrivetestthe coverageareaandinvestigateperformanceproblems. CDMA is a commonfrequency system.


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CDMA systemisaninflexible,whichrequiresarea-wideorclustertestingofcoverage.

Adjustments made to coverage power, antenna geometry or RF call processing

algorithmparameterswillimpactallsectorssharingthespectrumimage. Inaddition,

outsideordistantnoisesourcesmustbesurveyed,controlledorremovedifpossible.

The testermustresist the localizedchangesbut focusonchanges that improve the

overallclusterofcells areawidecoveragequality.

CDMA drive testing isperformed usingaphone connected toa portable computer.

Cellularand PCS subscribersviewtheperformanceoftheirserviceonthebasisofthe

networkcoverageorthecallquality. Thedrive-testtoolusesaphonetore-createthe

problems that a subscriber is experiencing. For example, if a subscribers call is

dropped whileoperating inamoving vehicle inaparticular location; thedrive -test

should be able to duplicate this problem.

Set up ofDrive Test

TWO CDMA PHONEONE RECEIVER;

1 .Laptop running E6474a software,with dongle attached

2. GSMReceiverx 1

3. Receiver cable x 1

4. RF Antenna + GPS Antenna x 1

5. Manifold Hub x 1

6. CDMA Kyocera QCP2235 phone x 2

7. CDMA Manifold phone cable (E6474-60139) x 2

8. USB cable x 1

9. 9 pin-9pin serial cable x 1


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10. Recei er power cable wit 2 pi M LEX power connector x 1

ongle USB cable C1

MA phone cable C1

MA PH2 NE Recei

3er cable

(GPS TRAK45

G F 6 R DR47

E TEST)


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The dri e test system is placed in a vehicle and driven throughoutthe

wireless service providers network coverage area.


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tata final project

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