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MOBILE COMMUNICATION

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PSTN

TRANSFER MODE : CIRCUIT SWITCHINGNETWORK TYPE : DIGITAL EXCEPT PART OF ACCESS

NETWORK CHANNEL CAPACITY : 64 KBPS

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CELLULAR SYSTEM

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CELLULAR MOBILE SYSTEM

• A WIRELESS MOBILE COMMUNICATIONNETWORK ENABLES USERS TO INITIATE ANDRECEIVE PHONE CALLS USING MOBILE PHONES

•

CELLULAR MOBILE TELEPHONY IS DIFFERENTFROM THE LANDLINE TELEPHONY IN THAT THEMOBILE SUBSCRIBER CAN INITIATE ANDRECEIVE CALLS WHILE ON MOVE WITHOUT ANYDISRUPTION IN THE CALL

• CELLULAR TELEPHONY DERIVES ITS NAMEFROM THE PARTITION OF A GEOGRAPHICAREA INTO SMALL PARTS CALLED “CELLS”

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CELLULAR MOBILE SYSTEM(CONTD.)

• EACH CELL IS COVERED BY A LOCAL TRANSMITTERAND RECEIVER POWERFUL ENOUGH TO ENABLECONNECTIVITY WITH CELLULAR PHONES (MOBILESTATIONS / MOBILE TERMINALS / MOBILEEQUIPMENT) WITHIN ITS AREA

• A SEPARATE RADIO FREQUENCY IS USED FOR EACHDIRECTION OF COMMUNICATION – MOBILE PHONE TO CELL SITE : UPLINK

TRANSMISSION – CELL SITE TO MOBILE PHONE : DOWNLINK

TRANSMISSION• THE SPECTRUM OF RADIO FREQUENCIES AVAILABLE

FOR COMMUNICATION IS LIMITED AND AREALLOCATED TO DIFFERENT CELLULAR

TECHNOLOGIES

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RADIO FREQUENCYALLOCATION TO MOBILE

COMMUNICATION

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CELLS

ANTENNATOWER

CELLS

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CELLS

• CELLS ARE SMALL SECTIONS OF AN AREAWITH ANTENNA, TRANSMITTER ANDRECEIVER

•

CELLS ARE DEFINED BY ITS – PHYSICAL SIZE

– SIZE OF POPULATION

• CELL RADII CAN VARY FROM HUNDREDS OF

METERS IN CITIES TO TENS OF KILOMETERS INCOUNTRY SIDE

• CELLS ARE REPRESENTED BY HEXAGON WITHHONEYCOMB PATTERN

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TYPES OF CELLS

• MACRO CELL – LARGE CELL WITH DIAMETER > !" KM – TRANSMITTER POWER ! TO # W

• MICRO CELL – SMALL CELL WITH DIAMETER OF UPTO ! KM – TRANSMITTER POWER "! TO ! W

•

PICO CELL – VERY VERY SMALL CELL – USED FOR INDOOR TRANSMISSION IN BUILDINGS OR TUNNELS

• SELECTIVE CELL – COVERAGE LESS THAN $#" DEGREES – USED TO FILL GAPS IN THE COVERAGE

• UMBRELLA CELL –

USED IN MICRO CELL BUT WITH DIFFERENT CHANNEL FOR TRANSMISSION – USAGE EXAMPLE % AT PLACES WHERE HEAVILY USED ROAD CROSSES THE MICRO

CELL AREA

THE FIRST THREE TYPES ARE BASED ON SIZE OF CELLTHE LAST TWO TYPES ARE BASED ON SPECIAL FUNCTIONS

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EVOLUTION OF MOBILECOMMUNICATION

• !4" : MTS # MOBILE TELEPHONE SYSTEM $ – MTS USED FREQUENCY MODULATION TECHNIQUE – IT USED SINGLE CARRIER FREQUENCY IN THE RABGE OF $& TO '& MH – HALF DUPLEX OPERATION – ALL CALLS HANDLED THROUGH OPERATOR – MOBILES PHONES HAD PUSHTOTALK SWITCH – & DIGIT MOBILE NUMBER – NO CONNECTIVITY WITH PSTN * MOBILE TO PSTN AND VICE VERSA

NOT POSSIBLE

• !64 : IMTS # IMPROVED MTS $ – SEVERAL CARRIER FREQUENCIES USED TO HAVE SIMULTANEOUS CALLS – NEED FOR OPERATOR WAS ELEMINATED – WIDE AREA COVERAGE – BASE STATION TRANSMITTER POWER !"" TO +"" W – MOBILE PHONE TRANSMITTER POWER & TO +& W – MOBILE PHONE NUMBERS OF SAME LENGTH AS PSTN NUMBERS. SO

MOBILE TO PSTN AND VICE VERSA CLLS WERE POSSIBLE

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EVOLUTION OF CELLULARNETWORK

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EVOLUTION OF CELLULARNETWORK

•

NMT – NORDIC MOBILE TELEPHONE ( '&" , -"" MH )

• AMPS – ADVANCED MOBILE PHONE SYSTEM ( &" MH )

• DAMPS – DIGITAL AMPS

• CDMA – CODE DIVISION MULTIPLE ACCESS SYSTEM

• GSM – GLOBAL SYSTEM FOR MOBILE COMMUNICATION ( TDMA -""

MH EUROPE)

• DCS – DIGITAL CELLULAR SYSTEM ( TDMA GSM !"" EUROPE )

• PCS – PERSONAL CELLULAR SYSTEM ( TDMA GSM !-"" US )

• UMTS – UNIVERSAL MOBILE TELECOM SYSTEM

•

IMT – INTERNATIONAL MOBILE SYSTEMS

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CELLULAR TELEPHONYSERVICES

• CELLULAR TELEPHONY HAS EVOLVED FROM BEING UST A VOICE SERVICE TO PROVIDING A RICHCOLLECTION OF VOICE0 DATA AND MULTIMEDIASERVICES

• KEY CELLULAR SERVICES % – TEXT MESSAGING (SMS) – INSTANT MESSAGING (CHAT) – MULTIMEDIA MESSAGING (MMS) – EMAIL – EMERGENCY CALLS – WIRELESS INTERNET – VIDEOONDEMAND – MOBILE TV – IP BASED MULTIMEDIA COMMUNICATION

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COMPARISON OF CELLULARSYSTEMS

PARAMETER AMPS TACS NMT4%" NMT!""FRE&UENCY

BAND#MH'$

("" !"" 4%" !""

CHANNEL

SPACING#KH'$

)" *% *% *+%

SPEECHMODULATIO

N

FM FM FM FM

SIGNALLING

FSK FSK FSK FSK

SIGNALLING

BIT RATE

" KBPS ( KBPS *"" BPS *"" BPS

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MEDIUM ACCESS CONTROL

• CHANNELIZATION IS A MULTIPLE ACCESSMETHOD IN WHICH THE AVAILABLEBANDWIDTH OF A LINK IS SHARED IN TIME0

FREQUENCY OR USING CODE BY NUMBER OFSTATIONS

• THE MEDIUM ACCESS CONTROL TECHNIQUESARE %

–FDMA ( FREQUENCY DIVISION MULTIPLE ACCESS )

– TDMA ( TIME DIVISION MULTIPLE ACCESS )

– CDMA ( CODE DIVISION MULTIPLE ACCESS )

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FDMA

•FRE&UENCY DIVISION MULTIPLE ACCESS•THE BANDWIDTH IS DIVIDED INTOSEPARATE GRE&UENCY BANDS

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TDMA

•TIME DIVISION MULTIPLE ACCESS•THE BANDWIDTH IS DIVIDED INTO TIME

SLOTS

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CDMA

•CODE DIVISION MULTIPLE ACCESS•DATA FROM ALL STATIONS ARETRANSMITTED SIMULTANEOUSLY

AND ARE SEPARATED BASED ONCODING THEORY

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COMPONENTS OF CELLULARNETWORK

• BASE TRANCEIVER STATION ( BTS )

• BASE STATION CONTROLLER ( BSC )

• MOBILE SWITCHING CENTRE (MSC )

OR MOBILE TELEPHONE SWITCHINGOFFICE (MTSO)

• LOCATION REGISTERS ( HLR VLR )

• AUTHENTICATION CENTRE ( A-C )

• LINKS TO PSTN

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BASE TRANVEIVER STATION(BTS)

• BTS CONSISTS OF – ELECTRONIC SECTION LOCATED AT THE BASE

OF ANTENNA TOWER AND INCLUDES• FREQUENCY AMPLIFIER•

RADIO TRANCEIVER• RADIO FREQUENCY COMBINER• CONTROL LINKS• COMMUNICATION LINKS TO BSC• POWER SUPPLY WITH BACKUP

–

ANTENNA AND FEEDER SECTION – INTERFACE BETWEEN BTS AND BSC

• CONTROL LOGIC• SOFTWARE

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BTS

• BTS LOCATION IN THE CELL0 HEIGHTOF ANTENNA AND ORIENTATION AREALL IMPORTANT FACTORS TO ENSURE

REQUIRED COVERAGE IN THE CELL• DIFFERENT LOCATIONS OF BTS ARE %

– CENTRE EXCITED CELL

– CORNER EXCITED CELL

– EDGE EXCITED CELL

SECTOREDDIRECTIONALANTENNA

OMNIDIRECTIONALANTENNA

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MOBILE SWITCHING CENTRE(MSC)

• MSC CONTROLS BSC.• ACTS AS SWITCH AND CONNECTION TO PSTN• ACTS AS AN AUTHENTICATION CENTRE (A1C)• CONTAINS REGISTERS * THE DATABASES

MAINTAINING MOBILE LOCATION INFO• CONTROLS CHANNEL ASSIGNMENT0 CALL

PROCESSING0 CALL SETUP AND TERMINATION0SIGNALLING0 SWITCHING AND SUPERVISION

• CONTAINS FACILITIES TO GENERATE BILLINGINFO FOR CUSTOMER ACCOUNTS

• IN VIEW OF ITS IMPORTANCE0 MANY BACKUP ANDDUPLICATE CIRCUITS ARE PROVIDED TO ENSURE

THAT THER ARE NO FAILURES

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AUTHENTICATION CENTRE(A1C)

• USER2S IDENTITY IS CHECKED TOPROVIDE AUTHENTICATION ANDENCRYPTION PARAMETERS

• A1C MAINTAINS A REGISTRATIONDATABASE OF USERS ALLOWED TOUSE THE NETWORK

• A1C FUNCTION IS NECESSARY FORSECURITY AS WELL AS BILLINGOPERATION

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EQUIPMENT IDENTITYREGISTER (EIR)

• EIR IS A DATABASE HOLDING DETAILS OF MOBILEPHONE EQUIPMENT IN THE FORM OF IMEI NUMBER

• IMEI ( INTERNATIONAL MOBILE EQUIPMENTIDENTITY ) NUMBER CAN BE ACCESSED ASFOLLOWS % – BY ENTERING 34"#4 ON MOBILE – ALSO PRINTED INSIDE THE PHONE

• EIR DATABASE IS USED TO PREVENT CALLS FROMSTOLEN0 UNAUTHORIZED MOBILE PHONES

• THE NETWORK OPERATORS MAINTAIN $ SEPARATELISTS OF IMEI IN THE EIR – GREY % MOBILE PHONES TO BE TRACKED – BLACK % BARRED MOBILE PHONES – WHITE % VALID MOBILE PHONES

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LOCATION REGISTERS ( HLR0VLR)

• HLR % HOME LOCATION REGISTER – CONTAINS SEMIPERMANENT INFORMATION OF

SUBSCRIBERS

– KEEPS USER PROFILE OF USERS REGISTERED WITH

THE NETWORK – MSC REFERS TO THE SUBSCRIBER INFORMATION IN

THE HLR

– THE HLR DATA OF A SUBSCRIBER IS STORED ASLONG AS THE SUBSCRIBER REMAINS WITH MOBILE

OPERATOR – HLR ALSO STORES CURRENT LOCATION OF THE

SUBSCRIBER AND SERVICES TO WHICH HE/SHEHAS ACCESS

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LOCATION REGISTERS ( HLR0VLR)

• VLR : VISITOR LOCATION REGISTER – CONTAINS TEMPORARY INFORMATION ABOUT THE MOBILE SUBSCRIBERS CURRENTLYLOCATED IN THE SERVICE AREA OF AN MSC

BUT WHOSE HLR ARE ELSEWHERE – ROAMING USER RECORD IS ADDED TO VLR

WHENEVER AN MSC DETECTS A NEW MOBILEPHONE IN ITS AREA

– THE MSC CONTACTS THE HLR OF THE MOBILESUBSCRIBER2S HOME LOCATION AND GETS

THE DETAILS REQUIRED TO VALIDATE THEUSER

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CONNECTING TO NETWORK

• WHEN A MOBILE PHONE IS SWITCHED 5ON20 IT NEEDS TOCOMMUNICATE WITH THE CELLULAR NETWORK TO REGISTER

• THE MOBILE PHONE USES A 5PAGING2 OR 5CONTROL2CHANNEL TO MAKE THE CONTACT WITH THE BASE STATIONAND SENDS 5ATTACH2 REQUEST

•

THE AUTHENTICATION CENTRE VERIFIES THE USER2SIDENTITY• ONCE VALIDATED0 THE HOME LOCATION REGISTER (HLR) AND

THE VISITOR LOCATION REGISTER (VLR) ARE UPDATED• PERIODICALLY0 EVEN IF THE MOBILE PHONE IS IDLE0 THE

MOBILE PHONE COMMUNICATES WITH THE BASE STATION TOUPDATE ITS STATUS AND LOCATION

• WHEN MOBILE PHONE IS SWITCHED 5OFF20 IT SENDS A5DETACH2 REQUEST TO THE BASE STATION

• THE NETWORK THEN UPDATES THE LAST KNOWN LOCATIONOF THE MOBILE IN THE DATABASE

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CLUSTER

• CLUSTER IS A GROUP OF CELLS• THE CELLULAR NETWORK AREA IS DIVIDED

INTO NUMBER OF CELLS• THESE CELLS ARE GROUPED INTO NUMBER

OF CLUSTERS• FOR HEXAGONAL CELLS0 POSSIBLE CLUSTER

SIZES ARE GIVEN BY THE FORMULA %

/ 0 12* 3 I 5 3 52*

W6787 592 :; 9

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CLUSTER (CONTD.)

• THE INTEGERS 5:2 , 52 DETERMINE THERELATIVE LOCATIONS OF COCHANNEL CELLS

• COCHANNEL CELLS CAN USE THE SAME

FRE&UENCIES• IN THE DIAGRAM0 CELLS WITH THE SAME

LABEL ARE COCHANNEL CELLS

• TO LOCATE A COCHANNEL CELL0 MOVE 5:2

CELLS0 TURN #" DEGREES COUNTERCLOCKWISE0 MOVE 52 CELLS IN THATDIRECTION

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LOCATING A COCHANNELCELL

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CELL PATTERN % CLUSTER OF $CELLS

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CELL PATTERN % CLUSTER OF CELLS

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NO. OF CHANNELS IN ACLUSTER

• NO. OF CHANNELS IN A CLUSTER ISGIVEN BY THE FORMULA %

F 0 G N

• WHERE0

– F % NO. OF FULL DUPLEX CHANNELSAVAILABLE IN A CLUSTER

– G % NO. OF CHANNELS IN A CELL

– N % NO. OF CELLS IN A CLUSTER

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TOTAL CHANNEL CAPACITY OF ANAREA

• TOTAL CHANNEL CAPACITY OF AN AREAIS GIVEN BY THE FORMULA %

C 0 7 G N

0 7 F• WHERE0

– C % TOTAL CHANNEL CAPACITY OF THE AREA – M % NO. OF CLUSTERS IN THE AREA –

G % NO. OF CHANNELS IN A CELL – N % NO. OF CELLS IN A CLUSTER – F % NO. OF CHANNELS IN A CLUSTER

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CHANNEL CAPACITY

• THUS0 THE CHANNEL CAPACITY OFCELLULAR NETWORK IS DIRECTLYPROPORTIONAL TO THE NO. OF

CLUSTERS IN THAT NETWORK

• 5N2 IS CALLED THE CLUSTER SIZEAND IS TYPICALLY $0 0 OR !+ CELLS

PER CLUSTER

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FREQUENCY REUSE

• FRE&UENCY REUSE IS THE PROCESS IN WHICHTHE SAME SET OF FRE&UENCIES # CHANNELS $CAN BE ALLOCATED TO MORE THAN ONE CELL

• FREQUENCY REUSE HAS BECOME ESSENTIAL DUE TO – LIMITED FREQUENCY SPECTRUM AVAILABLE FOR

CELLULAR MOBILE COMMUNICATION – TREMENDOUS GROWTH IN THE NUMBER OF MOBILE

USERS

• IT IS POSSIBLE TO REUSE A FREQUENCY OUTSIDE THE RANGE OF THE RADIO TRANSMITTER

•

CELLS IN A CLUSTER USE UNIQUE FREQUENCYCHANNELS. HOWEVER0 DIFFERENT CLUSTERSCAN USE THE SAME SET OF FRE&UENCIES

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FREQUENCY REUSE FACTOR( FRF )

• THE FREQUENCY REUSE FACTOR ISGIVEN BY THE EQUATION %

FRF 0 N 8 C

• WHERE0

– FRF % FREQUENCY REUSE FACTOR

– N % TOTAL NO. OF CHANNELS IN ANAREA

– C% TOTAL NO. OF CHANNELS IN A CELL

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REUSE DISTANCE

REUSE DISTANCE 9D 0 # $X R

WHERE, R : CELL SIDE, AND N:CLUSTER SIZE

)N

)N

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ADACENT CHANNELINTERFERENCE

• INTERFERENCE CAUSED BY TRANSMISSIONOF AD

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COCHANNELINTERFERENCE

• CELLS FROM DIFFERENT CLUSTERSUSING THE SAME FRE&UENCIES ARECALLED “COCHANNELS CELLS”

•

A CERTAIN MINIMUM DISTANCE MUSTSEPARATE THESE COCHANNEL CELLS INORDER TO AVOID THE INTERFERENCE

• FOR HEXAGONAL CELLS THE REUSE

DISTANCE IS GIVEN BY %REUSE DISTANCE 9D 0 # $X RWHERE, R : CELL SIDE, AND N:

CLUSTER SIZE9

)N

)N

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CELL SPLITTING

• CELL SPLITTING IS THE PROCES OFSUBDIVIDING THE CELLS INTO SMALLERCELLS EACH WITH ITS OWN BASE STATIONAND SET OF CHANNEL FRE&UENCIES

• SPLITTING OF CELLS ALLOWS AN INCREASE IN THEDEGREE OF FREQUENCY REUSE THUS INCREASING

THE CHANNEL CAPACITY OF CELLULAR NETWORK • IF THE RADIUS OF A CELL IS MADE HALF0 FOUR

TIMES AS MANY SMALLER CELLS COULD BECREATED TO PROVIDE SERVICE TO THE SAME

COVERAGE AREA• MAOR DRAWBACK OF CELL SPLITTING IS MORE

HANDOFF; PER CALL AND MORE PROCESSINGLOAD PER SUBSCRIBER

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CELL SPLITTING (CONTD.)

• EXAMPLE OF CELL SPLITTING %

– THE CHANNEL CAPACITY OF MACROCELLS WITH !" CHANNELS PER CELL !"

J " CHANNELS – AFTER SPLITTING THE MACRO CELLS INTO

' MINICELLS0 THE CHANNEL CAPACITY !" J J ' +" CHANNELS

– AFTER SPLITTING MINI CELL INTO ' MICROCELLS0 THE TOTAL CAPACITY !" J X 'X ' !!+" CHANNELS

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SECTORING

• THE COCHANNEL INTERFERENCE CAN BEREDUCED BY REPLACING A SINGLE OMNIDIRECTIONAL ANTENNA AT THE BASE STATION BYSEVARAL DIRECTIONAL ANTENNAS0 EACH

RADIATING WITHIN A SPECIFIED SECTOR• THIS TECHNI&UE OF IMPROVING SYSTEM

PERFORMANCE BY USING DIRECTIONALANTENNAS IS CALLED “SECTORING”

• A CELL IS NORMALLY PARTITIONED INTO THREE*"" SECTORS OR SIX 6"" SECTORS

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ROAMING

• ROAMING REFERS TO EXTENSION OFCONNECTIVITY SERVICE IN A LOCATION THAT ISDIFFERENT FROM THE HOME LOCATION WHERE

THE MOBILE SUBSCRIBER WAS REGISTERED

• ROAMING ENSURES THAT THE SUBSCRIBER CANCONTINUE WITH THE CALL WHEN MOVINGAWAY FROM HIS HOME LOCATION WITHOUTLOSING THE CONNECTION

• ROAMING IS POSSIBLE ONLY IF THERE IS ANAGREEMENT BETWEEN THE TWO NETWORKSPROVIDING SERVICES TO DIFFERENT AREAS

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ROAMING PROCESS

• WHEN A MOBILE DEVICE IS TURNED 5ON2 IN A NEW LOCATION0 THE VISITED NETWORK NOTICES THAT THE MOBILESUBSCRIBER IS NOT REGISTERED WITH IT AND ATTEMPTS TOIDENTIFY THE HOME NETWORK OF THE SUBSCRIBER

• IF ROAMING AGREEMENT EXISTS BETWEEN THE TWO

NETWORKS0 THE VISITED NETWORK CONTACTS THE HOMENETWORK AND REQUESTS SERVICE INFORMATION USING THEIMSI NUMBER

• IF SUCCESSFUL0 THE VISITED NETWORK MAINTAINS A TEMPORARY RECORD IN ITS DATABASE FOR THE SUBSCRIBER

•

LIKEWISE0 THE HOME NETWORK UPDATES ITS DATABASE WITH THE CURRENT LOCATION OF THE SUBSCRIBER SO THAT IT CANROUTE THE CALLS CORRECTLY TO THE MOBILE DEVICE

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HANDOFF / HANDOVER

• CONTINUITY OF SERVICE IS MAINTAINED BYSUPPORTING HANDOFF 8 HANDOVER PROCESSWHEN A MOBILE SUBSCRIBER MOVES FROM ONECELL TO ANOTHER

• IT IS A PROCESS OF CHANGING THE CHANNELRESOURCES #FRE&UENCIES, TIME SLOT, CODE,ETC$ ASSOCIATED WITH THE CURRENTCONNECTION WHILE A CALL IS GOING ON

•

IT IS INITIATED BY CROSSING A CELL BOUNDARY ORBY DETERIORATION IN THE QUALITY OF SIGNAL IN THE CURRENT CHANNEL

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TYPES OF HANDOFF;

• TWO TYPES OF HANDOFF; ARE USED%

– HARD HANDOFF

– SOFT HANDOFF

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HARD HANDOFF

• IT IS A BREAK BEFORE MAKEPROCESS

• CURRENT RESOURCES ARE RELEASED

BEFORE NEW RESOURCES ARE USED

• PRIMARILY USED IN TDMA / FDMANETWORKS

• THE BREAK IS SHORT ENOUGH TO BENOTICED BY THE USER

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SOFT HANDOFF

• IT IS A MAKE BEFORE BREAK PROCESS

• CONNECTION WITH THE TARGET BASESTATION IS MADE BEFORE THE CONNECTION

WITH THE EXISTING BASE STATION ISBROKEN

• COMMONLY USED IN CDMA NETWORKS

• THE SOFT HANDOFF GIVES MORE RELIABLE

CONTINUITY WITH LESS CHANCES OF CALL TERMINATION THAN THAT IN HARDHANDOFF

FURTHER CLASSIFICATION OF

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FURTHER CLASSIFICATION OFHANDOFF;

• NETWORK CONTROLLED HANDOFF

– NETWORK MAKES THE HANDOFF DECISION

• MOBILE ASSISTED HANDOFF

– MOBILE MEASURES THE SIGNALSTRENGTH0 BUT NETWORK MAKES THEDECISION OF HANDOFF

•

MOBILE CONTROLLED HANDOFF – MOBILE IS IN COMPLETE CONTROL OF THE

HANDOFF PROCESS

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MOBILE TO LANDLINE CALL

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• PREORIGINATION DIALING : WHEN SUBSCRIBER DIALS ANUMBER0 THE DIALED DIGITS ARE NOT TRANSMITTED0 BUT ARESTORED IN TH MOBILE MEMORY

• THE CALL PROCESS STARTS WHEN THE USER PRESSES 5SEND2 KEY

• THE MOBILE SCANS ALL THE DEDICATED CONTROL CHANNELS

AND LOCKS ONTO THE STRONGEST CHANNEL. ( CONTROL0PAGING0 AND ACCESS FUNCTIONS ARE ON THE SAME CHANNEL)

• WHEN THE REVERSE CONTROL CHANNEL (RECC) IS AVAILABLE0 THE MOBILE TRANSMITS A 5SERVICE REQUEST2 ON THE 5RECC2(CONSISTING OF DIALED DIGITS0 5ESN2 AND 5MIN2) TO THE CELLSITE

• CELL SITE FORWARDS THE REQUEST TO MSC

• MSC VALIDATES THE DATA (DIALED DIGITS0 5ESN2 AND 5MIN2) ANDROUTES HE CALL TO 5PSTN2


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MOBILE TO LANDLINE CALL(CONTD.)

• THE CELL SITE SELECTS AN IDLE VOICE CHANNEL AND TRANSMITSAN 5IVCDM2 (INITIAL VOICE CHANNEL DESIGNATION MESSAGE) TO THE MOBILE ON FORWARD CONTROL CHANNEL (FOCC)

• 5IVCDM2 CONTAINS THE VOICE CHANNEL NUMBER0 THESUPERVISORY AUDIO TONE (SAT) AND THE VOICE CHANNELMOBILE AUTHENTICATION CODE (VMAC)

•

SAT IS SNT ON THE ASSIGNED VOICE CHANNEL (FOVC)• MOBILE RECEIVES THE VOICE CHANNEL ASSIGNMENT0 TUNES TO

IT AND TRANSPONDS THE SAT ON REVERSE CONTROL CHANNEL5REVC2

• IF SAT IS LOST FOR & SECONDS OR MORE0 THE CALL IS DROPPED• WHEN THE CELL SITE RECEIVES THE SAT ON REVC0 BOTH AUDIO

PATHS ARE ENABLED AND MOBILE USER HEARS RINGBACK FROM

PSTN• WHEN THE CALLED PARTY ANSWERS0 THE CONVERSATION BEGINS• BLANK AND DATA BURST SIGNALLING IS USED TO TRANSMIT

CONTROL INFORMATION TO THE MOBILE DURING THE CALL

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LANDLINE TO MOBILE CALL

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• LANDLINE PARTY DIALS THE MOBILE NUMBER

• PSTN DETERMINES THAT THE CALL IS TO A MOBILE ANDROUTES THE CALL TO MSC

• MSC PERFORMS VALIDATION OF DIALED DIGITS

•

A PAGE MESSAGE IS SENT FROM MSC TO THE CELL SITE ONFORWARD CONTROL CHANNLE (FOCC)

• WHEN THE MOBILE SEES THE PAGE MESSAGE ON FOCC0 ITRESCANS THE CONTROL CHANNELS AND LOCKS ON THESTRONGEST ONE

• MOBILE TRANSMITS A PAGE RESPONSE MESSAGE ON THEREVERSE CONTROL CHANNEL (RECC)

• CELL SITE RECEIVES THE PAGE RESPONSE AND SELECTSAN IDLE VOICE CHANNEL


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LANDLINE TO MOBILE CALL(CONTD.)

• CELL SITE TRANSMITS ON THE FORWARD CONTROLCHANNEL (FOCC) AN 5IVCDM2 AND 5SAT2 ON FORWARDVOICE CHANNEL (FOVC) TO MOBILE

• MOBILE RECEIVES 5IVCDM2 ON FOCC0 TUNES TO THEASSIGNED VOICE CHANNEL AND TRANSPONDS 5SAT2 ON

REVERSE VOICE CHANNEL (REVC)• CELL SITE TRANSMITS AN ALERT ON FOVC TO THE

MOBILE ASKING THE MOBILE TO RING

• MOBILE STARTS RINGING AND TRNSMITS SIGNAL TONE5ST2 CONTINUOUSLY UNTIL THE CALL IS ANSWERED

• LOSS OF ST INDICATES THAT THE CALL HAS BEENANSWERED

• MSC NOW CONNECTS THE LANDLINE PARTY TO THEMOBILE AND CONVERSATION BEGINS

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MOBILE TO MOBILE CALL

• THE ORIGINATING MOBILE INITIATES THE CALL

• CELL SITE RECEIVES THE DESTINATION MOBILENUMBER AND ORIGINATING MOBILE2S ID ON REVERSECONTROL CHANNEL (RECC) AND FORWARDS IT TO MSC

•

MSC SENDS A PAGING SIGNAL TO ALL CELL SITES TOLOCATE THE DESTINATION MOBILE

• ONCE LOCATED0 THE DESTINATION CELL SITE SENDS APAGING SIGNAL TO THE DESTINATION MOBILE TODETERMINE IF IT IS 5ON2

• AFTER RECEIVING A POSITIVE RESPONSE FROM THEDESTINATION MOBILE0VOICE CHANNELS ARE ASSIGNED

TO BOTH ORIGINATING AND DESTINATION MOBILES

MOBILE TO MOBILE CALL

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MOBILE TO MOBILE CALL(CONTD.)

• CALL PROGRESS TONES ARE APPLIED IN BOTH THEDIRECTONS ( RING AND RINGBACK)

• WHEN THE STSTEM RECEIVES ANSWER FROM THEDESTINATION MOBILE0 CALL PROGRESS TONES ARE

TERMINATED AND CONVERSATION BEGINS• IF THE SYSTEM FINDS THAT

– ALL VOICE CHANNELS ARE ALLOCATED

• SENDS 5RETRY2 SIGNAL

– DESTINATION MOBILE IS ON A CALL

• SENDS 5BUSY2 SIGNAL

– DESTINATION MOBILE NUMBER IS INVALID

• SENDS 5CALL CAN NOT BE PROCESSED2 SIGNAL

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1669697.ppt